History of Science And Technology

I.S.S.N. 1722 6961 - EPMagazine 15, vol. 5, issue 3, December 2007
EPM
Discover your own way to enjoy science at school
EPMagazine
THIS PROJECT HAS BEEN FUNDED BY THE EUROPEAN
COMMISSION. THE VIEWS EXPRESSED IN THE ARTICLES
DO NOT NECESSARILY COMPLY WITH THE ONES OF THE
EUROPEAN COMMISSION AND EPM EDITORIAL BOARD.
1st Cover: http://office.microsoft.com/it-it/clipart/results.aspx?qu=barometro&sc=20
EPMagazine is an international Scientific Periodical
Published by a pool of European Schools
European Pupils Magazine
Discover your own way to enjoy science at school
www.epmagazine.org
www.liceoboggiolera.it/epm
www.biology4u.gr/pupmag.html
Co-ordinators
Headmasters
Ali Kalem
[email protected]
Stelios Friligkos
[email protected]
Hatice Uzug
[email protected]
Angelo Rapisarda
[email protected]
Yunus Cengiz
Nikolaos Georgolios
Adnan Dinc
Giovanni Torrisi
Web Editorial Board
Webmaster:
Web assistant:
Multimedia CD:
Rick Hilkens [email protected]
Gabriele Viglianisi
[email protected]
Gianfranco Distefano
[email protected]
Italian Editorial Board
Τeachers: Viviana Dalmas, Antonino Porto, Angelo Rapisarda
Students: Angela Pinzone, Angelo Tambone, Ersilia Rappazzo
Claudio Arena, Lorenzo Bianchetti
Francesco Manuncola Trovato
Layout: Paolo Catania and Graziano Troina
History of Science and Technology
CONTENTS
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History of Science and Technology
European Pupils Magazine
year 5, number 3, 2007
EPM 15 - I.S.S.N. 1722-6961
EPMagazine is an international
Scientific Magazine published by a
pool of European Schools
Editorial: Contributions in Italian,
English, Greek, Turkish
By Angela Pinzone
10th EPM project meeting
Kayseri 14th -20th November 2007
By Nikos Georgolios, Theodosia
Karaoglani
What do students think about
science?
By Soustas Panagiotis
My Barometer
14
Vasile Melinte, Mihaela Diaconescu
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The Solar System
Il Sistema Solare
16
14/16
23
Luigi Prestinenza
The evolution of the Atomic Model
L’evoluzione del Modello Atomico
Andrea Savia
History of Science and Technology
European Pupils Magazine
14/16
32
Medicine In Ancient Egypt
Ιατρικη Στην Αρχαια Αιγυπτο
14/16
37
Black Holes
Ioakeimidou Erato
Exintara Evagelia
I Buchi Neri
Claudio Arena
FUN
48
What is What in Astronomy?
17/19
49
Ecplipse:
a mystery in the ancient times
Eclissi: un mistero nell’antichità
17/19
54
59
Vangelis Voultsinos
Manuele Gangi
Following Galileo footstep …
Ακολουθώντας
τα βήµατα του Γαλιλαίου ...
Lenia Kokkinou, Antonis
Varvianis, Lina Kexagia
Guidelines For Contributors
Angela Pinzone
E
Liceo Statale “E. Boggio Lera”
www.liceoboggiolera.it
[email protected]
EDITORIALE
EDITORIAL
Cari lettori,
Dear readers,
A qualche settimana di distanza dal 10° EPMeeA few weeks after the 10th EPMeeting, which
took place in Turkey, here we are to sum up the ting, tenutosi in Turchia, eccoci qui a tirare le somme dell’esperienza da poco vissuta.
experiences we enjoyed.
10th EPMeeting
was an exciting time,
full of inputs for the
organization of EPM
and
for
the
intercultural meeting.
The exchange of
ideas lies in the use of
a common language,
English,
which
enables EPM editors
to try their hands and
improve their abilities
in a foreign language.
CAPPADOCIA
During the Meeting the title of
the new project (Many countries, a
common point: science) and the
layout for 2008 were decided;
moreover the mirror sites and the
new CD of EPM were proposed.
In the Meeting we had the
chance of comparing Turkish,
Greek and Italian cultures.
So EPMeetings are a good
opportunity to get to know,
appreciate and respect the
customs and the traditions of
cultures different from our own.
The Italian Editorial Board of
EPM will never forget the
hospitality of Turkish partners,
from whom we received a very
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EPM GROUP
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Il 10° Meeting si è
rivelato un’esperienza
elettrizzante, ricca di
input sia per quel che
riguarda gli aspetti organizzativi di EPM,
che per quel che riguarda l’incontro interculturale.
Lo scambio di idee
si fonda sull’uso strumentale della lingua
inglese, che consente ai
redattori di EPM di
mettersi in gioco e di
acquisire una maggiore sicurezza
nell’utilizzo della lingua straniera.
Durante il Meeting è stato deciso
il titolo del nuovo progetto (Tanti
Paesi, un punto in comune: la
scienza), il layout per il 2008; inoltre
sono stati presentati i siti mirror e il
nuovo CD di EPM.
Il Meeting è diventato anche
l’occasione per il confronto tra cultura turca, greca e italiana.
I convegni di EPM risultano
quindi essere un’ottima occasione
anche per conoscere, apprezzare e
soprattutto rispettare le abitudini e
le tradizioni di culture diverse dalla
propria.
Il gruppo italiano di EPM porterà
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EPM
History of
Science and Technology
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EDITORIAL
EDITORIALE
KAYSERI
CAPPADOCIA MOUNTAINS
warm welcome.
With this wonderful heap of memories, we are
going to face the 11th EPMeeting , which will be
held in April, in the Greek city of Thessaloniki.
per sempre il ricordo dell’ospitalità dei partner turchi, che ci hanno riservato un’accoglienza calorosa
sin dal primo istante.
We hope we
shall be able to
add a further
piece
of
experience, so
that the editorial
board may get
better and better.
EPM STAFF
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We wish the
EPMeeting to
give unity and
compactness to
the group and
that new stimuli,
brought by the
other partners,
will improve our
m a g a z i n e
making it more
Con questo meraviglioso bagaglio di ricordi ci
avviamo ad affrontare, ad Aprile, l’11° Meeting,
che si terrà nella città greca di Salonicco.
La nostra speranza è quella di aggiungere un ulteriore tassello alla nostra esperienza all’interno della redazione di EPM.
Ci auguriamo infatti che il EPMeeting possa
servire per dare unità e compattezza al gruppo e che
nel corso dell’incontro con gli altri partner possano
maturare dei nuovi stimoli che migliorino il giornale
rendendolo sempre più attraente e produttivo.
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EPM TEACHERS
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History of
Science and Technology
BAŞYAZI
ΕΚ∆ΟΤΙΚΟ ΣΗΜΕΙΩΜΑ
Değerli Okuyucular,
Αγαπητοί αναγνώστες,
Λίγες βδοµάδες
µετά τη 10η συνάντηση
του
EPM
στην
Τουρκία, είµαστε εδώ
για να συνοψίσουµε τις
εµπειρίες που ζήσαµε.
Η 10η συνάντηση
ήταν µια συναρπαστική
ευκαιρία
γεµάτη
καινούργια στοιχεία,
για την οργάνωση του
EPM αλλά και µια
ευκαιρία συνάντησης
α ν θ ρ ώ π ω ν
διαφορετικής κουλτούρας.
Η ανταλλαγή ιδεών γίνεται
σε µια κοινή γλώσσα, την
Αγγλική, που δίνει την
δυνατότητα στους εκδότες του
EPM να συνεργαστούν στενά
και να βελτιώσουν την
ικανότητά τους στην χρήση µιας
ξένης γλώσσας.
T ü r k i y e ’ d e
gerçekleşen 10. EPM
toplantısından bir kaç
hafta sonra, yaşadığımız
tecrübeleri aktarmak
amacıyla karşınızdayız.
10. EPM toplantısı,
EPM organizasyonu için
ve kültürlerarası iletişim
için pek çok katkı ile dolu
eğlenceli bir zamandı.
EPM editörlerinin
yabancı bire dilde kendi
becerilerini geliştirme ve
LAKE IN URGUP REGION
ç a b a g ös t e r me l e r i n i
sağlayan, yabacı dilin yani İngilizce’nin
kullanımında, fikirlerin paylaşılması yatar.
Toplantıda, yeni projenin
başlığı (Çok sayıda ülke, bir
ortak nokta: Bilim) ve 2008 için
yeni dergi tasarımı Kabul edildi;
ayrıca yani web siteleri ve yeni
EPM CD’si sunuldu.
Toplantıda, İtalyan, Türk ve
Yunan kültürlerini karşılaştırma
fırsatı bulduk.
Κατά την διάρκεια της
Συνάντησης, αποφασίστηκαν: ο
Bu yüzden, EPM toplantıları,
τίτλος του καινούργιου
kendimizden başka kültürlerin
Προγράµµατος («Πολλές
geleneklerini ve adetlerini
Χώρες, ένα κοινό σηµείο: Η
öğrenme, takdir etme ve saygı
Επιστήµη») και η σελιδοποίηση
duymak için iyi bir fırsattır.
του περιοδικού για το 2008.
Ακόµη έγιναν προτάσεις για τα
EPM’in İtalyan Editör
mi r r or si t e s (αντί γραφο
grubu, kendileinden çok sıcak bir
δικτυακού τόπου) και τα CDs
EPM TEACHERS IN KAYSERI
karşılama gördüğümüz Türk
του EPM.
Στη συνάντηση είχαµε την ευκαιρία να ekibinin misafirperverliğini asla unutmayacak.
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BAŞYAZI
ΕΚ∆ΟΤΙΚΟ ΣΗΜΕΙΩΜΑ
γνωρίσουµε στοιχεία από τον Τουρκικό, Ελληνικό
και Ιταλικό πολιτισµό.
Εποµένως οι συναντήσεις του EPM είναι µια
καλή ευκαιρία Να Γνωρισεις, Να Εκτιµησεις Και
Να Σεβαστεις τις συνήθειες και τις παραδόσεις
διαφορετικών πολιτισµών από τον δικό σου.
Η ιταλική συντακτική οµάδα του EPM δεν θα
ξεχάσει ποτέ την φιλοξενία των Τούρκων εταίρων,
οι οποίοι µας υποδέχτηκαν πολύ θερµά.
KAYSERI MOSQUE
Με αυτές τις
θαυµά σιες
αναµνήσεις,
βαδίζουµε προς
τ η ν
1 1 η
Συνάντηση του
EPM , που θα
γίνει τον Απρίλιο
στην
Ελλάδα,
στην πόλη της
Θεσσαλονίκης.
Bu güzel hatıra yığını ile, Selanik,
Yunanistan’da nisan ayında yapılavak olan 11.
EPM toplantısını karşılayacağız.
Editör Grubunun daha da iyileşeceği, daha iyi
deneyimler hazanmayı umuyoruz.
Toplantının, gruba birlik ve beraberlik
getirmesini ve dergimizi geliştirecek yeni stimuliyi
ortaya çıkarmasını umuyoruz.
Ελπίζουµε ότι
θα µπορέσουµε
EPM CLOSET IN BUNYAN
να προσθέσουµε
περισσότερες εµπειρίες, ώστε ως συντακτική
οµάδα να γινόµαστε καλύτεροι και καλύτεροι.
Ευχόµαστε η Συνάντηση να κάνει πιο ενωµένη
και συµπαγή την οµάδα και ότι νέα ερεθίσµατα θα
προκύψουν ώστε να βελτιώσουν ακόµη
περισσότερο το Περιοδικό µας.
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OZKAN SCHOOL
9
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NEWS
10th EPM PROJECT MEETING
KAYSERI 14th -20th NOVEMBER 2007
Nikos Georgolios, Theodosia Karaoglani
Experimental School of University of Macedonia
Thessaloniki, Greece
[email protected]
The 10th EPMeeting took place in two towns, Incesu and Bunyan, in Kayseri region between 15th
and 20th November 2007. The host schools were M. Ozkan Anatolian High School (Incesu) and
Bunyan Anatolian High School.
The other contributing partners were Experimental High School of Univ. Macedonia (Neapoli,
Thessaloniki, Greece) 4 teachers-4 pupils and Liceo Boggio Lera (Catania, Italy), 1 teacher-2 pupils.
The guest schools arrived in Kayseri with the
same flight on the 14th November and they enjoyed
a very warm and impressive welcome by teachers,
students and host families of the two schools.
EPM PARTNERS IN INCESU
During the first two days, the meeting took
place in M. Ozkan Anatolian High School (Incesu)
and during the last two days in Bunyan Anatolian
High School.
At both schools the guests were welcomed by the
Headmaster and the teachers of each school.
They were guided to the facilities of the school
and some teachers had also the opportunity to
attend some courses.
The main program of the meeting included presentations of all
partners about what had been done so far for the Magazine. This
work was summarized and checked by the Italian student Angela
Pinzone.
The main problems of the work were presented by the Greek
group, which concerned the delay of printing the issues, the
dissemination of the Magazine and the poor communication
among partners.
A lot of discussion followed in order to find the proper ways to
face these problems. All partners agreed to do their best to
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EPM PARTNERS IN BUNYAN
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Discover your own way to
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improve the dissemination of the magazine and to speed the printing of issues. Hence, a schedule of
tasks was made to share the work to be done.
In addition, the cover of the 2008 issues was decided and finally the name of the project, which
will be submitted to the E.U. for the next two years, was selected after voting.
The prize award ceremony for the competition of the best article of 2006 was postponed for the
meeting in Thessaloniki, on April 2008, since the two winners from Greece (A. Deligiorgi and S.
Diskou) did not manage to come to Kayseri.
Except the official sessions, the students from Greece and Turkey presented interesting subjects
of general interest as Ionian philosophers, common words in Greek, Turkish and Italian.
All partners had also the opportunity to participate in other activities. In Incesu they had been
received by the Mayor, who welcomed the foreign delegations. And then they visited the historical
and cultural places of Incesu.
They also had a cultural walk in downtown Kayseri and they visited the local market.
CAPPADOCIA REGION
On Sunday they visited the city of Urgup and
the underground town of Derinkuyu in Nevsehir
region and they enjoyed the unique landscape of
Cappadocia region.
Finally, they had lunch by a lake in Urgup
region.
The last day of the meeting, the farewell dinner
took place in Erkilet, in a restaurant with a
wonderful view located on the hills surrounding
Kayseri.
LUNCH AT THE LAKE
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All guests felt thankful to their partners from
Kayseri not only for the organization of a perfect
meeting but for their warmth and hospitality.
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NEWS
WHAT DO STUDENTS THINK ABOUT SCIENCE?
Soustas Panagiotis
Experimental School of University of Macedonia,
Thessaloniki, Greece
[email protected]
At the 8th EPMeeting in Thessaloniki (November 2006) a project was produced based on a
questionnaire whose questions concerned the science course and the way it is taught in Greek
schools. This included the likeability of students about science, their opinion about the difficulty of
the lesson, the time they spend reading it, their need or not of help and the way through which they
get it.
It would be very interesting if we had opinions from other European students about the teaching
of Science in their countries.
The answers were 75 out of 75 persons and the questions were:
Do you like science?
Is it difficult?
How much time do you spend reading science?
Do you need help for it?
100
80
like science
60
don't like
science
don't like
science at all
40
20
Do you like science?
• 46% likes science
• 45% doesn’t like science
• 8% doesn’t like science at all
0
100
Is it difficult?
80
60
Very difficult
40
Easy
Very easy
20
• 29% answered that science is very difficult
• 65% answered that it is easy
• 6% answered that it is very easy
0
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100
80
Do you need help?
60
don't need help
Need help
40
20
• 61% doesn’t need help
• 39% needs help
0
100
80
1 hour
60
2hours
40
More than 2
hours
20
How much time do you read science?
• 58% reads less than 1 hour
• 33% reads less than 2 hours
• 8% reads more than 2 hours
0
100
90
80
70
60
50
40
30
20
10
0
Extra lessons
Help from books
Help from parents
Both help from
parents and books
No help
If you need help what kind of help do you need?
• 43% does not need help
• Parents help the 26%
• 14% has extra books that help the students
explain the lesson and solve the exercises
• 10% has extra lessons
• 6% has help books and is helped by parents
Some suggestions
Generally students are not happy with the way that science is taught in schools. Especially with the
books, which are very difficult to read because they use complicated words. Things should get better
for Greek students.
Firstly we should visit the laboratories more often. We can also modify the books by adding and
abstracting topics, which are easier. This can be done with the help of our teachers. Thus all the
students will understand some of the implicit points of the books.
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NEWS
MY BAROMETER
Vasile Melinte, Mihaela Diaconescu
Colegiul Tehnic “Gh. Asachi”
Iasi, Romania
[email protected]
The word barometer is derived from the Greek word baros, meaning weight, and the Greek word
metron, meaning measure.
Mercury barometers are built according to the principle of Torricelli’s tube, in its turn based on
Pascal’s Law (the hydrostatic pressure is equal to the atmospheric pressure Po). As an application,
we calculated the normal atmospheric pressure equal to 1 Atm or 1.013 x 105 N/m2
Metallic barometers rely on the deformation of one or more metallic cans under the action of the
atmospheric pressure. In this way, taking the measure in the same place once or even several times a
day, we can notice that it can vary around the normal value. These variations are connected with the
atmosphere status.
METALLIC BAROMETER
TORRICELLI’S TUBE
AN ANTIQUE BUT STILL
FUNCTIONAL BAROMETER
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Barometers measure air pressure but they were also
used for measuring altitude, or height above the ground,
such as the height of a mountain, and they were often used
to measure altitude aboard a hot air balloon. They were
also used by miners in caves to determine the depth of a
mine.
Starting from these historical, scientific and practical
grounds, we started to build a barometer using recyclable
materials. We will reveal the recipe according to which we
executed the practical activity and which we recommend to
the pupils who are fond of technique and science.
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Necessary materials
- a large coffee cup (or something similar to it)
- rigid straw
- a rubber elastic which is shorter than the circumference of the cup
- a balloon
- scale paper (or a ruler)
- adhesive tape
- scissors
Mode of acting
You are supposed to cut the mouth of the balloon in order to make a latex cuff. Then you must
stretch the balloon over the mouth of the cup and fix it with the elastic. The straw must be fixed to
the balloon. The barometer will be left several days near a wall or a vertical surface.
The scale paper or ruler must be fixed to the wall and the place where the end of the straw lies is
to be marked. Now you can start to gauge it by comparison with the indications of the barometer in
the laboratory. You must measure the atmospheric pressure for 2 or 3 days, using more barometers
in order to be able to compare the values obtained.
BAROMETER – SIDE 2
BAROMETER – SIDE 1
Bibliography
Garabet M., Neacşu I., Lectii experimentale in laboratorul de fizica, Editura Niculescu, 2002
Hristev A., Manda D., Fizică-manual pentr clasa a IX-a, Editura Didactică şi Pedagogică,
Bucureşti, 1989.
Petrescu-Prahova M., Bârzu I., Fizică-manual pentru clasa a VII-a, Editura Didactică şi
Pedagogică, Bucureşti, 1984.
www.barometer.ws/history.html
Iconography
www.navy.mil.za
Acknowledgements: Elena Melnig, Tamara Slatineanu
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Luigi Prestinenza
No profit association Stelle e Ambiente, Catania, Italy
www.stelleambiente.it
[email protected]
[email protected].
IL SISTEMA SOLARE
THE SOLAR SYSTEM
THE AIRBAG OF THE ROVER PATHFINDER
GLI AIRBAG DEL ROVER PATHFINDER
The human race in the last fifty years has
made important changes in the knowledge of the
solar system (where our Earth is the third planet)
not only for the great progression in the use of
advanced instruments of observation, capable of
extending the investigation beyond the visible
radiation but, above all, for the contribution of
Hubble telescope, in orbit outside the atmosphere.
Moreover, the direct recognitions were led by
equipped and sophisticated probes.
In fact, various planets were approached at
distances of a few thousand kilometres, or space
shuttles came down on their surface, as in the case
of the Moon (the unforgettable evening, 20th July
1969), Mars; asteroids like Eros, comets nuclei
and in 2002 even Titan, Saturn’s largest moon, 2
billion km far from the Earth.
Speaking of rediscovery is neither
presumptuous nor exaggerated: there is much
more to discover, to explain rationally, but the
progress made was huge and it paved the way for
new and unpredictable investigations.
To achieve these goals is only a matter of time
and will, but first of all it is necessary to invest
resources, brains and money.
Some probes are completing the exploration
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Gli ultimi cinquant’anni hanno portato a una
totale riscoperta del sistema solare di cui la nostra Terra è il terzo pianeta: ciò è dovuto non solo
a i grandi progressi nell’impiego di strumenti
d’osservazione sempre più progrediti e in grado di
estendere l’indagine al di là della stretta finestra
delle radiazioni visibili, ma soprattutto a
l’apporto del telescopio Hubble, messo in orbita
fuori dall’atmosfera.
In particolar modo, le sonde sempre più attrezzate e sofisticate hanno condotto ricognizioni speciali, avvicinando i vari pianeti a distanze di poche migliaia di chilometri, o addirittura scendendovi sopra, come è avvenuto dopo la Luna
(l’indimenticabile serata del 20 luglio 1969), per
Marte, per asteroidi come Eros e nuclei cometari
e nel 2002 addirittura per Titano, la più grande
delle molte lune di Saturno, distante da noi quasi
due miliardi di chilometri.
Parlare di riscoperta non è dunque esagerato
né presuntuoso: certo, v’è molto ancora da scoprire, da spiegare razionalmente, ma il passo avanti
compiuto è stato gigantesco, e soprattutto ha aper-
THE PROBE CASSINI LAUNCHED TO TITANO
LA SONDA CASSINI VERSO TITANO
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History of
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of Mercury, the nearest planet to the sun. There are
probes that photograph Mars with its peculiarities
and there are robots that creep on the reddish
ground and analyse its composition.
Others are approaching Pluto, the farthest
planet from the Sun and it is considered as a dwarf
planet for its diameter. Finally, there is the
discovery of a series of objects beyond Neptune,
some of which overcome the distance of the far
planet dedicated to the God of Hell.
We might get to know the Solar System better
thanks to the improvement of more and more
sophisticated technologies, which are advanced,
efficient and less expensive than before.
Werner von Braun hoped to explore Mars (the
first planet in our imagination) with a fleet of space
ships, but he was unable to do it.
He wanted to begin his exploration because in
the last year of 18th century and in the first part of
19th century, some specialists observing the surface
of the red planet, formulated some hypotheses about
THE EARTH
LA TERRA
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THE COMETS SWAM
LA COMETA SWAM
to la strada a nuove indagini tali da rivelare molto di
ciò che vorremmo conoscere. A questo fine non
mancano i mezzi d’indagine: è questione di tempo e
di volontà, ma soprattutto di risorse da investire,
cervelli e investimenti.
Intanto, ci sono sonde in volo per completare
l’esplorazione di Mercurio, il pianeta più vicino al
Sole, sonde che fotografano Marte sin nei particolari, robot che addirittura strisciano sul suo suolo rossastro analizzandolo nei molteplici aspetti e nella
composizione, e anche sonde in volo verso il remoto Plutone, di questi mondi il più lontano dal Sole e
da poco addirittura retrocesso a pianeta nano per il
suo modesto diametro; infine, la scoperta, a
quell’enorme distanza, di un’intera fascia di oggetti
transnettuniani, cioè collocati oltre Nettuno, qualcuno dei quali addirittura eguaglia o supera in dimensioni il lontano mondo dedicato al dio degli Inferi.
Dobbiamo quindi aspettarci sempre nuovi oggetti da studiare, via via che aumentano le possibilità di
raggiungerli con metodi sempre più efficaci e di costo contenuto. Non con la flotta spaziale di astronavi che Wernher von Braun sperava di mettere in
viaggio verso Marte, il pianeta che da sempre ha il
primo posto nell’immaginazione dei Terrestri.
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the presence a web of dark lines linking the bluegreen areas in both hemispheres.
If it really existed, a sort of canal’s system would
apparently be necessary, which could distribute the
insufficient water resources of this world from the
unique water supply of polar snows to the temperate
areas or to the equator.
Lots of scientists were sceptic about this
hypothesis; in fact, it was demolished by the
observations of astronomers as the Italian Vincenzo
Cerulli, or the French–Greek Eugenios Antoniadfi
at the beginning of the 20th century.
The geometric–lined canals were explained by
the exploration of the eye, on the limit of perception,
of irregular details, shades, little spots of various
sizes.
In this way a big step forward was made in the
reconstruction of the real environment of Mars,
thanks to closer images taken by the probes flying
over the planet since 1964 (the American Mariner
5).
However, the legend of the Martian was hard to
die, like all the legends stimulating our imagination.
The balance of what we know, and of what we have
checked, shows us that in the solar system there are
DIONE, SATURN’S SATELLITE
DIONE, SATELLITE DI SATURNO
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ENCELADO, ONE OF SATURN’S SATELLITES
ENCELADO, UNO DEI SATELLITI DI SATURNO
Vediamo perché: negli ultimi anni
dell’Ottocento e ai primi del Novecento, osservazioni inattese di esperti specialisti autorizzarono a
credere che, sul pianeta rosso esistesse tutta una
ragnatela di linee oscure che congiungevano le aree
blu-verdastre osservate nei due emisferi. Se effettivamente esistevano, si sarebbe dovuto pensare a una
sorta di canalizzazione e immaginare che fosse tale
per distribuire le scarse risorse idriche di questo
mondo dall’unica riserva d’acqua delle nevi polari
sino alle lontane contrade delle zone temperate o
dell’equatore.
Una tale ricostruzione lasciò scettici molti scienziati e fu confutata dalle osservazioni di astronomi
come il teramano Vincenzo Cerulli o il francogreco Eugenios Antoniadfi a cavallo dei primi del
Novecento. Le linee geometriche dei canali furono
spiegate con la sintesi operata dall’occhio, al limite
della percezione, di dettagli irregolari, sfumature,
macchiette di vario diametro. E fu fatto così un gran
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THE SOLAR SYSTEM
IL SISTEMA SOLARE
few areas where life can exist as it happened during
the first Earth’s geological ages: Mars has the same
levels of the dense and deep atmosphere as Venus
and Jupiter, maybe also Jupiter’s satellite Europa
is covered by ices that are probably floating upon a
liquid ocean; finally the big moon of Saturn, Titan,
wrapped in a dense atmosphere.
For the other planets there is not much to
hope….
The small Mercury, the planet nearest to the
Sun, has alternatively oven heats and glacial
temperatures. Venus’s hot arid ground is furrowed
by huge lava flows and it is covered by a dense
atmosphere of carbonic gases.
The Moon and the asteroids between Mars and
Jupiter are much too small to retain an appreciable
atmosphere.
The big external planets like Jupiter and
Neptune contain gases. Pluto is very cold with its
moon Charon; much colder are the big asteroids
over Neptune in the dark and frozen depths
announcing interplanetary space.
So, discovering more about other planets is very
interesting like every time a veil, wrapping
something unknown, is torn open.
We have also strange cases.
For example there are asteroids shaping an
equilateral triangle between Jupiter and Sun, called
Trojans, because they have a Homeric name.
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passo avanti nel ricostruire il reale ambiente di
Marte, così come è, e come l’hanno mostrato, in
peggio, le immagini ravvicinate delle sonde che lo
sorvolarono fin dal 1964 (l’americano Mariner 5).
Ma la leggenda dei Marziani, industriosi costruttori di canali è stata lenta a morire, come tutte
le leggende che accarezzano e stimolano la nostra
sensibilità e immaginazione.
Il bilancio di ciò che conosciamo e abbiamo potuto verificare ci mostra, in tutto il sistema planetario della stella Sole, poche aree dove la vita abbia
possibilità di nascere e di svilupparsi, come è avvenuto nei lontani giorni delle prime ere geologiche
terrestri: il sottosuolo di Marte, certi livelli delle
dense e profonde atmosfere di Venere e di Giove,
forse anche il satellite gioviano Europa, coperto di
ghiacci che forse si stendono sopra un oceano liquido; infine, la grande luna già citata di Saturno, ovvero Titano, avvolta da una densa atmosfera.
19
IO, JUPITER’S FIFTH SATELLITE
IO, IL QUINTO SATELLITE DI GIOVE
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Moreover, around
the external planets,
there are rings made of
carbonic gases or ice.
There
are
thousands of comets
going through different
planetary
orbits,
approaching the Sun
and then going back to
black and frozen
external spaces.
And more, there
are the NEO Near
Earth
Orbiting,
asteroids, closer to
Earth
orbiting
representing
a
continuous threat for
our planet.
MERCURY
MERCURIO
Many planets, many
questions even more as
they regard the formation and the evolution of the
System, kept together by the Sun’s force of
gravity.
It is 1000 times bigger than the other planets.
Moreover, there are specific questions concerning
the different spatial bodies that we can study.
The purpose of Planetary Astronomy, more
difficult than the Stellar one, is to study all these
worlds, big and small, hot and frozen. The planets
do not shine of their own light, but they reflect the
Sun light, with bands added by their atmospheric
gases as our spectroscopes have revealed.
The nearest planets to the Sun are difficult to
observe because of its shining light, still the far ones
are more difficult to observe, dipped in the faint,
dusky light that the Sun itself manages to spread
over them.
It is easier, instead, to study stars because their
spectre reveals us the gases contained, the
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Per il resto, c’è poco da sperare: diviso fra calori
da forno e temperature glaciali, il piccolo Mercurio, il pianeta più vicino al Sole; ancora più caldo
l’arido suolo di Venere, solcato da enormi colate
laviche e avvolto da una densa atmosfera di gas
carboniosi; troppo piccoli la Luna e gli asteroidi
della fascia fra Marte e Giove per trattenere
un’atmosfera apprezzabile; fatti essenzialmente di
gas i grossi pianeti esterni, da Giove a Nettuno,
freddissimo Plutone con la sua grande luna Caronte; ancora più gelati i grossi asteroidi che si vanno
scoprendo oltre Nettuno, nelle profondità buie e
gelide che annunciano ormai lo spazio interplanetario.
E tuttavia questa scoperta, questa progressiva
rivelazione di tanti mondi ha un suo fascino, come
sempre quando cade il velo che avvolge qualcosa di
sconosciuto.
Non mancano poi i casi più singolari: asteroidi
che fanno triangolo equilatero con Giove e il Sole,
detti troiani perché recano nomi
omerici, gli anelli di materia
carboniosa o di
ghiacci attorno
ai pianeti più
esterni, migliaia
di comete che si
infilano fra le
diverse orbite
planetarie,
si
approssimano al
Sole e poi tornano indietro, puntando verso i
neri e gelidi spazi esterni; e ancora i NEO Near Earth OrbiTHE MOON
ting, gli asteroi-
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di vicini all’orbita della nostra Terra, che rappresentano una continua minaccia, per le loro orbite
perturbate che talora addirittura rasentano il nostro
pianeta.
Tanti mondi, tanti interrogativi: molti di più, anzi, perchè ci sono quelli di carattere più generale,
che riguardano la formazione e l’evoluzione del
sistema, tenuto assieme dalla forza di gravità del
Sole, la stella che sta nel centro, con una massa mille volte superiore a quella di tutti i pianeti messi
assieme; e i quesiti particolari sui diversi corpi che
via via si offrono alla nostra indagine.
SATURN
SATURNO
temperature, the age and the probable evolution
during the long periods of the Universe.
Photography and probes have made wonders in
revealing many details of these worlds, a lot of
which were studied for their residual and
insufficient heat, in general very close to the
Absolute Zero.
This is the case of the asteroids of EdgeworthKuiper band, situated beyond Neptune.
A similar panorama deserves young people’s
attention, together with the knowledge of our Earth:
the luckiest planet, in which the light of
intelligence shines.
Iconography
www.nasa.gov, NASA (National Astronomic Sky
Agency)
http://dayton.hq.nasa.gov/IMAGES/MEDIUM/
GPN-2000-000484.jpg, GRIN, great images in
NASA, Steve Garber
www.skylive.it/forum5/topic.asp?
TOPIC_ID=4967, Unione Astrofili Italiani,
Franco Lanza
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Studiare e conoscere a fondo tutti questi mondi,
grandi e piccoli, roventi o gelati, è il compito
dell’astronomia planetaria, ancor più difficile e
ardua di quella stellare: perché i pianeti non brillano di luce propria, riflettono quella del Sole, con
bande aggiunte
dai loro gas atmosferici che si
rivelano
allo
spettroscopio.
Difficili da osservare
quelli
più vicini al Sole, nella luce abbagliante di questa stella; ancor
più difficili quelli lontani, immersi nel debole
chiarore crepuscolare che il
Sole stesso riesce a far giungere sino a laggiù.
Più facile, al
SHOEMAKER-LEVY 9
confronto, stu- THE COMET
AND JUPITER
diare le stelle, LA COMETA SHOEMAKER-LEVY 9 E
GIOVE
che ci dicono già
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quasi tutto col loro spettro: i gas che contengono, la
temperatura, persino l’età e la possibile evoluzione nei lunghi tempi del Creato.
La fotografia e le sonde hanno fatto meraviglie
nel rivelare molti dettagli di questi mondi; molti, i
più remoti, come gli asteroidi della fascia di Edgeworth-Kuiper, posta al di là di Nettuno, vengono
studiati addirittura in base al loro residuo e scarso
calore, di molto vicino agli abissi dello zero assoluto.
Un simile panorama merita tutta l’attenzione dei
giovani, accanto alla conoscenza della nostra Terra:
il pianeta più fortunato, quello in cui brilla la luce
dell’intelligenza, che tante cose spiega e interpreta,
senza peraltro dar fondo al mistero.
THE SUN
IL SOLE
www.skyandtelescope.com, Sky and Telescope
(USA), Richard Tresch Fienberg, various issues
of this magazine
www.lestelle-astronomia.it, Le Stelle, Margherita
Hack, various issues of this magazine
www.coelum.com, Coelum, Francesco Mazzotta,
various issues of this magazine
www.orione.it, Nuova Orione, Francesco Bertuzzi,
Paolo Morelli, various issues of this magazine
http://uai.it/web/guest/home, Astronomia (UAI),
Emilio Sassone Corsi, various issues of this
magazine
www.bo.astro.it/sait/giornale.html,Giornale di
Astronomia, Fabrizio Bònoli, various issues of
Bibliography
Cesare Guaita, Alla ricerca della vita nel sistema
solare Sirio ed. Milano 2005
William Sheehan, The research of the ghost planet;
William Sheehan, The planet Mars
E. M. Antoniadi, La planète Mars Hermann Paris
1929
Mentore Maggini, Il pianeta Marte. Hoepli. 1939;
Giovanni Virginio, Schiaparelli Opere, voll. I, II, V,
Hoepli Milano 1886-92
Fresa, "la Luna", Hoepli
Piero Bianucci, "La Luna", Giunti ed. Firenze
Luigi Prestinenza, Marte fra storia e leggenda, ed.
UTET
Luigi Prestinenza, La scoperta dei pianeti ed. Gremese Roma 2007
Magazines Sky and Telescope (USA), Le Stelle,
Luigi Prestinenza, journalist and astrologer has been interested in astronomy, especially Planetary
Astronomy, for about fifty years. He has recently published Marte fra storia e leggenda (UTET) and La
scoperta dei pianeti (Gremese, Rome) reviewed and published according to the latest researches.
Luigi Prestinenza, giornalista e astrofilo, si occupa di astronomia, soprattutto planetaria, da più di
cinquant’anni; ha pubblicato di recente Marte fra storia e leggenda (UTET) e La scoperta dei pianeti
(Gremese, Roma), quest’ultimo appena uscito e aggiornato fino alle ricerche più recenti.
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Andrea Savia
Liceo Statale E. Boggio Lera
Catania, Italy
[email protected]
THE EVOLUTION OF
THE ATOMIC MODEL
L’EVOLUZIONE DEL
MODELLO ATOMICO
The object of this paper is the description of
the matter structure through the enumeration of
the major part of the theories formulated about it,
in the last centuries. To understand the
elementary constitution of the matter the
experiments executed by the scientists through
the time will be cited.
L’obiettivo di questo articolo è la descrizione
della struttura della materia attraverso l’elencazione
della maggior parte delle teorie formulate su di essa
negli ultimi secoli. Per spiegare le ipotesi relative
alla costituzione elementare della materia saranno
citati alcuni degli esperimenti eseguiti dagli scienziati.
Since ancient times man tried to
Fin dall’antichità l’uomo ha
give some answers to the question
cercato di dare delle risposte alle
regarding the constitution of the
domande riguardanti la costituziomatter: What is it composed of?,
ne della materia: Di che cosa è
fatta?, Fino a quale punto è posHow far is it possible to subdivide
it?
sibile suddividerla?
The ancient Greeks had two
Su questo secondo aspetto gli
different theories: some affirmed its
antichi Greci avevano due teorie
endless divisibility, others that it was
differenti: alcuni affermavano la
composed by elementary units.
sua infinita divisibilità, altri riteThese were only philosophic
nevano che fosse costituta da unitheories, without any reliable
tà elementari. Si trattava, comunscientific investigation. On the bases
que, di teorie filosofiche, senza
of this last theory some philosophers
alcuna indagine scientifica attensuggested some models, among
dibile. Tra i modelli ipotizzati è
them, Democritus, who affirmed
interessante citare quello creato
DEMOCRITUS
that all the matter was constituted by
da Democrito, il quale affermò
DEMOCRITO
an infinity of indivisible units, the
che tutta la materia era costituita
atoms (which in Greek means indivisible), and
da un’infinità di unità indivisibili, gli atomi (che in
that the atoms had no qualitative property taste,
greco significa indivisibile), privi di proprietà qualismell, color, but were characterized by
tative, sapore, odore, colore, ma caratterizzati da
quantitative property, such as dimension, shape
proprietà quantitative, cioè la grandezza, la forma e
and position.
la posizione.
The atomistic hypothesis of Democritus was
L’ipotesi atomistica di Democrito venne poi abthen abandoned, but it has been revisited in recent
bandonata ma è stata ripresa con altre modalità in
times.
tempi recenti.
The study of the matter, with a modern
scientific method, was started by Antoine
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Lo studio della materia, con un metodo scientifico moderno, fu avviato da Antoine Lavoisier con la
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Lavoisier with
the law of the
conservation
of the mass,
followed
by
Joseph Proust
with the law of
the
definite
proportions
and by John
Dalton with
the law of the
THOMSON ATOMIC MODEL
multiple
MODELLO
ATOMICO DI THOMSON
proportions
and with his atomic theory (1803), which asserted
that the matter was composed by a great number
of indivisible particles, that is the atoms, among
which, those of the same element are all equal
and have the same mass and cannot be created,
nor destroyed.
With the discovery of the X rays, in 1895 by
William Roentgen, and with the photoelectric
effect of Albert Einstein, the scientists realized
that they had to review the atom’s concept. In
1904 J. J. Thomson through the study of the
cathode rays found out the electrons, that is little
particles with very small mass and negative
charge, which was calculated by Robert
Millikan, and also other particles of opposite
charge and major mass.
On the basis of these results in 1906
Thomson suggested that the atom wasn’t
indivisible, but constituted of a positive spherical
structure into which the electrons where equally
displaced so to render altogether the atom neutral.
Thomson’s model was contradicted by the
experiments carried out by Ernest Rutherford,
and by his students, Geiger e Marsden, with the
alpha particles. In fact, Rutherford, bombarding
with these particles a thin gold sheet, observed
that the greatest part of them maintained the
direction of the start, some were lightly deviated
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legge della conservazione della massa, seguito da
Joseph Proust con la legge delle proporzioni definite e da John Dalton con la legge delle proporzioni
multiple e con la sua teoria atomica (1803), secondo la quale la materia era costituita da un gran numero di particelle indivisibili, cioè gli atomi, fra i
quali quelli di uno stesso elemento sono uguali fra
loro, hanno uguale massa e non possono essere né
creati, né distrutti.
Con la scoperta dei raggi X, nel 1895, di Wilhelm Roentgen, e con l’effetto fotoelettrico di Albert Einstein, gli scienziati capirono che si doveva
rivedere il concetto di atomo. Nel 1904 J. J. Thomson attraverso lo studio dei raggi catodici, scoprì gli
elettroni, cioè particelle con massa piccolissima e
carica negativa, che venne calcolata da Robert Millikan, e anche altre particelle di carica opposta e di
massa maggiore. Sulla base di questi risultati nel
1906 Thomson ipotizzò che l’atomo non fosse indivisibile, ma costituito da una struttura sferica positiva dentro la quale erano dislocati equamente gli elettroni, tanto da rendere complessivamente neutro
l’atomo.
Il modello di Thomson fu messo in crisi dagli
esperimenti effettuati da Ernest Rutherford, e dai
suoi allievi Geiger e Marsden, con le particelle
alfa. Infatti Rutherford, bombardando con queste
particelle una sottile lamina d’oro, notò che la maggior parte di esse mantenevano la direzione di partenza,
altre
venivano leggermente deviate e una
piccolissima
percentuale
veniva respinta. Se il modello
di
Thomson fosse stato valido,
RUTHERFOR’S EXPERIMENT
si sarebbe osESPERIMENTO DI RUTHERFORD
servata la stes-
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and a very small percentage
sa deviazione per ogni particelwas repelled. If Thomson’s
la, perché, secondo lui, le carimodel had been correct, the
che positive e negative dovevasame deviation for every
no essere disposte in modo oparticle would be noticed,
mogeneo all’interno dell’atomo.
because, in his opinion, the
positive and negative charge
Secondo questi dati, contrashould be disposed in a
stanti con il modello di Thomhomogeneous way into the
son, Rutherford ipotizzò che
atom.
l’atomo fosse costituito da un
Following these data, in
nucleo, nel quale risiede la
opposition with Thomson’s
maggior parte della massa atomodel,
Rutherford
mica e la carica positiva
supposed that the atom was
(giustificando la deviazione di
RUTHERFOR’S ATOM
made of a nucleus, much
alcune particelle alfa a causa
ATOMO DI RUTHERFORD
more smaller than the atom
della repulsione), e dagli eletin which the major part of the atomic mass and
troni che gli ruotano attorno velocemente per manthe positive charge (justifying the deviation of
tenere il proprio equilibrio fra l’attrazione esercitata
some alpha particles because of the repulsion )
dal nucleo e la reciproca repulsione.
resides, and of the electrons which turn around
quickly to maintain their own balance, between
Nel 1920 egli assegnò al nucleo atomico il nome
the attraction exercised by the nucleus and the
di protone, affermando che esso poteva essere forreciprocal repulsion.
mato anche da più protoni, e che in ogni atomo il
numero dei protoni e degli elettroni doveva essere
In 1920 he gave to the atomic nucleus the
uguale. Questo modello era in disaccordo con le legname of proton, affirming that it could be formed
gi della teoria elettromagnetica classica, in quanto
by more protons and in each atom the number of
l’elettrone ha una carica e, quindi, essendo acceleraprotons and electrons should be
to, avrebbe dovuto irradiare energia,
equal. This model belied the laws
cadendo in pochi istanti sul nucleo,
fenomeno che avrebbe dovuto comof the classic electromagnetic
theory, because the electron has a
portare l’emissione di tutte le frecharge and therefore, being
quenze nel passaggio dal suo livello
accelerated, it should irradiate
al nucleo. Queste ipotesi non trovano
energy, falling in few instants on
riscontro nella realtà in quanto gli atothe nucleus, a phenomenon which
mi sono stabili perché non hanno una
would involve the emission of all
loro frequenza di emissione.
its frequencies in the passage from
its level to the nucleus. These
Nel 1913 Niels Bohr rielaborò il
hypotheses cannot be proved in
modello ipotizzato da Rutherford,
reality in that the atoms are stable,
prendendo spunto dai risultati di Max
because they don’t have a fixed
Planck e Albert Einstein. Il primo
emission frequency in the
aveva introdotto, al di fuori della fisiNIELS BOHR
spectrum.
ca classica, il concetto di quantizza-
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In 1913 Niels
zione, in base al quale
Bohr
improved
una grandezza può assumere solo certi valori
Rutherford’s model
taking cue from the
permessi e l’energia non
results of Max
viene emessa in modo
Planck and Albert
continuo ma in quanti;
Einstein. The former
il secondo estese il conintroduced, out of the
cetto di quanto alla luclassic physics, the
ce, dicendo che essa era
concept
of
costituita da quanti, cioquantization, that is
è fotoni. Complessivaa quantity can take
mente il modello atomionly
certain
co di Bohr si basava su
permitted values and
due principi: la quantizthe energy isn’t
zazione delle orbite, in
emitted
in
a
base al quale l’elettrone
continuous way, but
poteva occupare solo
in quanta; the latter
determinate orbite, e la
extended the concept
quantizzazione
of quantum to the
dell’energia, in base al
BOHR’S ATOMIC MODEL
light, asserting that it
quale, quando un eletMODELLO ATOMICO DI BOHR
was composed by
trone percorre una certa
quanta, that is the photons. Altogether Bohr’s
orbita, non emette o assorbe energia, a meno che
atomic model was based on two principles: the
transiti da un’orbita a un’altra.
quantization of the orbits, that is the electron
Questo modello però aveva dei difetti perché
could occupy only determinate orbits, and the
non poteva essere applicato agli atomi con più di un
quantization of the energy, that is when a
elettrone e non riusciva a spiegare, secondo dei crielectron covers a certain orbit it doesn’t emit or
teri, la distribuzione nelle orbite degli elettroni.
absorb energy, except in the case in which the
Bohr infatti trattava sempre gli elettroni come delle
electron passes from an orbit to an other.
particelle classiche a cui poteva applicare le leggi
This model had some disadvantages because it
della meccanica.
couldn’t be applied to the atoms with more than
one electron and could not explain the
La svolta si ebbe nel 1925 con la teoria avanzata
distribution of the electrons into the orbits. Bohr,
da Louis De Broglie che iniziò a considerare
in fact, always handled the electrons as classic
l’elettrone con proprietà corpuscolari e ondulatoparticles to which he could apply the laws of the
rie; questa teoria fu sperimentalmente verificata da
mechanic.
Davisson e Germer che bombardarono con un fascio di elettroni un cristallo di nichel ed ottennero la
In 1925 there was a turning-point with the
stessa diffrazione che si osservava nei raggi X (già
theory formulated by Louis De Broglie, who
era stata assegnata questa duplice proprietà alle rabegan to consider the electron with corpuscular
diazioni). Queste nuove scoperte portarono alla naand undulated property; this theory was verified
scita della fisica quantistica, dal momento che alla
experimentally by Davisson and Germer,
materia fu assegnata la dualità onda-particella.
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bombarding a crystal of nickel with a band of
electrons and obtaining the same diffraction,
which was observed in the X rays (this double
property to the radiation had just been assigned
them). These new discoveries brought about the
rise of quantum physics, from the moment that
the wave-particle duality was given to the matter.
In 1926 Erwin Schrodinger formulated a
mathematic equation, which described the
behavior of the electron as a wave, into which,
following Max Born’s opinion, the square of the
absolute value of the wave width of a electron
represented the probability to find the electron in
a point of the space around the nucleus. In this
way the electron is represented only as a wave,
which behaved as a particle.
Since then the concept of the orbit was
abandoned and it was substituted by the concept
of orbital, that is the region of space into which it
is more probable to find an electron around the
nucleus.
One year later Werner Heisenberg developed
the knowledge of the atomic structure, noticing
that it wasn’t possible to know at the same time
the position and the exact moment of an
elementary particle, because of the principle of
indetermination.
In the following years a long series of
discoveries of particle until then unknown began;
in 1932 James Chadwick discovered the neutron
experimentally; successively Carl David
Anderson discovered the antiparticle of the
electron, the positron. With the study of natural
radioactivity of Henri Becquerel the scientists
began to doubt of the elementariness of the proton
and neutron. In fact in the beta decadence the
atom emits bands of electron from the nucleus.
To explain this phenomena Enrico Fermi
introduced the existence of another particle, the
neutrin, found experimentally by Fred Reiners
and Charles Cowan.
In 1937 the muon was discovered with a mass
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Nel
1926
Erwin Schrodinger formulò
un’equazione
matematica che
descriveva
il
comportamento
dell’elettrone
come onda, nella quale, secondo Max Born, il
quadrato del valore
assoluto
dell’ampiezza
dell’onda di un
elettrone rappresentava la proWERNER HEISENBERG
babilità di trovare l’elettrone in un punto dello spazio attorno al nucleo. In questo modo l’elettrone veniva rappresentato solamente come un’onda che si comportava da
particella.
Da allora in poi si abbandonò il concetto di orbita, che venne sostituito dal concetto di orbitale, cioè la regione di spazio nella quale è più probabile trovare un elettrone attorno al nucleo.
Un anno più tardi Werner Heisenberg, sviluppò
le conoscenze sulla struttura atomica, rilevando che
non era possibile conoscere contemporaneamente
sia la posizione sia l’esatto momento di una particella elementare, con il principio di indeterminazione.
Negli anni seguenti ebbe inizio una lunga serie
di scoperte di particelle fino ad allora sconosciute;
nel 1932 James Chadwick scoprì sperimentalmente
il neutrone, successivamente Carl David Anderson
scoprì l’antiparticella dell’elettrone, il positrone.
Con lo studio della radioattività naturale di Henri
Becquerel si iniziò a dubitare dell’elementarità del
protone e del neutrone. Infatti nel decadimento beta l’atomo emetteva fasci di elettroni dal nucleo. Per
spiegare questo fenomeno Enrico Fermi introdusse
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about 200 times bigger than
l’esistenza di un’altra particelthat of the electron and with
la, il neutrino, trovato speria negative charge.
mentalmente da Fred Reiners
Around 1963
the
e Charles Cowan.
physical Murray GellMann and George Zweig
Nel 1937 venne scoperto il
supposed that the proton
muone con massa circa 200
and the neutron were
volte quella dell’elettrone e con
composed by quarks
carica negativa.
(particle with a factional
Intorno al 1963 i fisici Murcharge, which couldn’t
ray Gell-Mann e George
exist individually because
Zweig ipotizzarono che il proof the strong attraction);
tone e il neutrone fossero costithese hypotheses were
tuiti da quark (particelle con
confirmed later by the
carica frazionaria, che non
results obtained from the
potevano esistere singolarmenparticles accelerator of the
te a causa della potente attraSTRONG NUCLEAR FORCE
CERN, in Genève.
zione); ipotesi che vennero sucFORZA NUCLEARE FORTE
The quarks, which have
cessivamente confermate dai
been found so far are six: d (down), u (up), s
risultati ottenuti dagli acceleratori di particelle del
(strange), c (charm), b (bottom), t (top).
CERN, a Ginevra.
The proton is composed by two quarks u and
I quark che sono stati finora individuati sono 6:
one d; the neutron is composed by two quarks d
d (down), u (up), s (strange), c (charm), b
and one u.
(bottom), t (top).
Il protone è formato da due quark u e uno d; il
Actually it is thought that all the universe is
neutrone è formato da due quark d e uno u.
ruled by four fundamental forces: the strong
nuclear force, which is manifest in the nucleus
Allo stato attuale si pensa che tutto l’universo sia
among the quarks; the weak
governato da quattro forze fondanuclear force, which is seen in
mentali: la forza nucleare forte, che
the nuclear reactions or in the
si manifesta all’interno del nucleo tra
radioactive decadence; the
i quark, la forza nucleare debole,
electromagnetic force, which is
che si osserva nelle reazioni nucleari
observed in the atom since it
o nel decadimento radioattivo, la forbinds the electrons to the nucleus;
za elettromagnetica, che si osserva
the gravity force, which is
nell’atomo in quanto lega gli elettroni
manifest in the planetary system
con il nucleo, e la forza gravitazioand in the fall of the bodies.
nale, che si manifesta nei sistemi plaFollowing this theory the
netari e nella caduta dei corpi.
interactions among the particles
take place thanks to the
Secondo questa teoria le interazioELEMENTARY PARTICLES
exchanges of energy, that is of the
ni tra le particelle avvengono tramite
PARTICELLE ELEMENTARI
quanta, to which the name of
degli scambi di energia, cioè di quan-
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ti, a cui viene dato il
mediating
particles
is
nome di particelle
given.
mediatrici.
Following
the theories and
Utilizzando le
the discoveries
teorie e le scoperte
of the last forty
degli
ultimi
years
the
quarant’anni si è
scientists arrived
arrivato a un modelto a model,
lo, chiamato Modelcalled Standard
lo Standard, seconModel, which
do il quale le partiexplains that the
celle elementari di
tutta la materia preelementary
particles of all
sente nell’universo
the
matter
sono raggruppabili
present in the
in tre famiglie: i
universe
are
leptoni (particelle
assemble able in
elementari
comLARGE HADRON COLLIDER
three families:
p r e n d e n t i
the leptons (elementary particles which include
l’elettrone, il muone, il tauone e i loro corrisponthe electron, the muon, the tau and their
denti neutrini); i quark e le particelle mediatrici
corresponding neutrins); the quarks and the
(gravitone, fotone, gluone, mesoni e vettori bosomediating particles (graviton, photon, gluon,
ni intermedi).
meson and intermediate boson vectors).
Even if this model seems very detailed, it has
Anche se questo modello sembra molto dettasome imperfections. In fact, it can only link the
gliato, esso presenta alcuni difetti. Infatti, riesce a
electromagnetic force with the weak nuclear
unificare soforce. Scientists are trying to include that strong
lamente
la
nuclear force through some experiments, but
forza elettrothey aren’t able to insert the gravity force,
magnetica
because they have not found its mediating
con
quella
particle (the graviton).
nucleare deThis model suggests that the particles have all
bole. Si sta
the same speed of the light, property that really
cercando di
isn’t noticed, therefore they suppose the presence
includere
of an other kin of particle, called Higgs’s boson,
quella nuclenot yet proved experimentally, but that they
are forte atexpect to find it out in the Large Hadrons
traverso alcuCollider, in Genève.
ni esperimenAnother modern much accredited theory is the
ti, ma non si
theory of the laces, which suggest that all the
riesce a inseTHEORY OF THE LACES
elementary particles are composed by equal laces
rire la forza
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or
strings,
gravitazionale,
with the only
anche
perché
difference in
non è stata indithe kind of
viduata la sua
vibration,
particella mediawhich defines
trice (il gravitothe properties
ne).
to the particle
itself.
The
Questo movibration
dello
prevede
doesn’t take
che le particelle
place in a
abbiano tutte la
CLASSIC ATOMIC MODEL
t h r e e velocità
della
MODELLO ATOMICO CLASSICO
dimensional
luce, proprietà
kind of space, but can also arrive to nine
che realmente non viene riscontrata, quindi si ipotizdimensions, plus the time dimension. There are
za la presenza di un altro tipo di particella, detta bosome other slightly different theories, though.
sone di Higgs, ancora non rilevata sperimentalmenNowadays these theories aren’t considered
te, ma che viene ricercata soprattutto nel Large Haconvincing and are object of many doubts.
dron Collider (LHC) a Ginevra.
The models always come from the intuition of
some scientists and are considered valid so far as
they are able to explain the observed phenomena.
When later, because of other discoveries, they are
no longer satisfactory, the model is elaborated
again, sometimes even radically as the case of the
passage from the classic physics to the quantum
physics, so that it is nearer to the new reality. No
model can therefore be considered final and the
new continuous discoveries demand the
formulation of more and more complex models.
Un’altra teoria moderna molto accreditata è la
teoria delle stringhe, la quale sostiene che tutte le
particelle elementari sono costituite da cordicelle o
stringhe tutte uguali, con la sola differenza nel tipo
di vibrazione, che definisce le proprietà della particella stessa. La vibrazione non avviene in uno spazio di tipo tridimensionale, ma può arrivare anche a
nove dimensioni, più quella temporale. All’interno
di questa teoria ce ne sono altre leggermente differenti tra di loro. Attualmente queste teorie non sono
considerate convincenti e sono oggetto di molti dubbi.
Bibliography
La struttura dell’atomo agli inizi del ‘900: Rutherford – Liceo Scientifico G. Galilei, Dolo,
Riccardo Canonizzo, 22/12/2007, http://
galilei-dolo.provincia.venezia.it/2006_2007/
Energia%20Nucleare/NSEN_La%
20struttura%20dell'atomo%20agli%
2 0 i n i z i % 2 0 d e l % 2 0 9 0 0 %
20Rutherford_1.htm
Struttura dell’atomo: cenni storici, Università de-
I modelli nascono sempre dalle intuizioni di alcuni scienziati e vengono considerati validi fino a
che sono in grado di spiegare i fenomeni osservati.
Quando poi, alla luce di altre scoperte, essi non sono
più soddisfacenti, si rielabora il modello, a volte anche radicalmente, come nel caso del passaggio dalla
fisica classica a quella quantistica, rendendolo in
grado di rispecchiare la realtà. Nessun modello può
dirsi, quindi, definitivo e le nuove continue scoperte
richiedono la formulazione di modelli sempre più
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History of
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gli studi, Messina, Antonino Giannetto,
19/12/2007, http://ww2.unime.it/cclchim/
generale/atomo/atomo.htm
Modello atomico, Evoluzione, Liceo Statale, Volterra,
Enrico
Giachè,
19/12/2007,
www.liceovolterra.it/giache/
ModelloAtomico_Evoluzione.pdf
Dai primi modelli atomici, Paolo C. Corigliano,
19/11/2007, www.profcorigliano.it/
DOWNLOAD/EVOLUZIONE%
20MODELLI%20ATOMICI.pdf
Modelli atomici, INFN, Bari, M. Bonifacio, C.
D’Aponte, M. T. De Bellis, R. Del Vecchio, R.
Pannarale, http://oldserver.ba.infn.it/
~garuccio/didattica/SSIS_03_04/
modatomici.pdf
Dall’atomo ai quark, ISISS Carlo Anti, Villafranca,
Alfio Pennisi, Andrea Bernardelli, Daniele Di
Giovine e Marco Scapinello, 30/05/2001,
www.carloanti.it/preside/news/
infinitamentepiccolo/L'atomop11.htm
Da Democrito a Schrodinger, Liceo N. Copernico,
Bologna, 14/12/2007, www.copernico.bo.it/
subwww/weboriana/filehtml/
le__varie_rappresentazioni__dell.htm
La struttura dell’atomo, Università agli studi, Firenze, P. Vanni, 06/05/2005, www.scibio.unifi.it/
lezioni/atomo.html
L’atomo dal rinascimento alla meccanica quantistica, Istituto per i Processi Chimico-Fisici del
CNR, Pisa, Giovanni Villani, Liberato Cardellini, http://wwwcsi.unian.it/educa/filoscien/
atomormq.html
La teoria quantistica, Istituto Nazionale di Fisica
Nucleare, www.infn.it/multimedia/particle/
paitaliano/history/quantumt.html
Il sapere attuale, il Modello Standard 1964 – 1998,
Istituto Nazionale di Fisica Nucleare,
www.infn.it/multimedia/particle/paitaliano/
history/smt.html
Introduzione alla fisica delle particelle ed al modello
standard, INFN, Pisa, Giorgio Chiarelli,
16/03/2006, www.df.unipi.it/~guada/PLSF/
epm
complessi.
Iconography
Democritus, La filosofia e suoi eroi,
www.filosofico.net/democ.html
Thomson’s model, ISISS Carlo Anti, Villafranca,
30/05/2001, www.carloanti.it/preside/news/
infinitamentepiccolo/L'atomop07.htm
Rutherford’s Experiment and Classic Atomic
Model, Liceo Artistico, Venezia, S. Marziali,
http://las.provincia.venezia.it/discscien/
chimica/lucecoloriipert1/rutherford.htm
Rutherford’s Atom and Theory of Laces, , Astronomia.com, Buchi Neri, Il paradosso
dell’informazione, pubblicato in: Astrofisica,
21/06/2007 ,Gabriella Bernardi,
www.astronomia.com/2007/06/21/buchineri-il-paradosso-dellinformazione
Niels Bohr, S.M.S., E. Filippini, Cattolica, S.M.S.
A. Serpieri, S. Giovanni in Marignano,
www.cattolica.info/cultura/fisica/biblioteca/
personaggi/bohr.htm
Bohr’s Atomic Model, Answers.com technology,
Introduction to quantum mechanics,
www.answers.com/topic/introduction-toquantum-mechanics?cat=technology
Werner Heisenberg, Stefano Pasini, 24/12/2007,
www.stefanopasini.it/Aurora-Dramatis_%
20Personae.htm
Strong
Nuclear
Force,
http://
knightstrife.altervista.org/Pagine/
Forza_Forte.htm
Particelle elementari, Irene Amodei e Marco Del
Mastro, Borborigmi di un fisico renitente,
23/01/2007,
www.bivacco.net/
marco/2007/01/23/il-bosone-di-higgsspiegato-a-oliver
Large Hadron Collider, Il CERN, 50 anni di ricerca in fisica dal Dipartimento di Fisica, Roma
Tre, 24/11/2007, http://xoomer.alice.it/
31
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Ioakeimidou Erato
Exintara Evagelia
Experimental School of University of Macedonia
Thessaloniki, Greece
[email protected]
MEDICINE IN
ANCIENT EGYPT
ΙΑΤΡΙΚΗ ΣΤΗΝ
ΑΡΧΑΙΑ ΑΙΓΥΠΤΟ
Introduction
Modern medicine owes a lot to the Ancient
Egyptians. In the beginning man could not explain
all that happened around him so he attributed it to
supernatural powers. He thought diseases were
caused by evil spirits or were a punishment coming
from a divinity. So physicians were simultaneously
both priests and magicians.
Εισαγωγη
Η Σύγχρονη Ιατρική οφείλει πολλά στους
αρχαίους Αιγυπτίους. Στην αρχή, επειδή ο
άνθρωπος δεν µπορούσε να εξηγήσει όλα όσα του
συνέβαιναν, άρχισε να τα αποδίδει σε
υπερφυσικές δυνάµεις. Οι αρρώστιες θεωρήθηκαν
έργα κακών πνευµάτων ή τιµωρία από µια
θεότητα.
Έτσι, οι γιατροί ήταν συγχρόνως και ιερείς και
µάγοι. Αυτές οι ιδέες επικρατούσαν σε όλους τους
λαούς της αρχαιότητας. Στην αρχαία Αίγυπτο ο
θεραπευτής θεός ήταν η θεά Ίσιδα, στην αρχαία
Ελλάδα ο Ασκληπιός, στη Φοινίκη ο Εσµούν.
Ο Imhotep, ο γνωστότερος αιγύπτιος
παθολόγος ήταν αστρονόµος και αρχιτέκτονας. Ο
Imhotep λατρεύτηκε ως θεός της Θεραπείας και
της Ιατρικής. Το άγαλµα του σήµερα βρίσκεται
στη Στοά των Αθανάτων στο ∆ιεθνές Κολέγιο
Χειρουργικής του Σικάγου. Η Peseshet ήταν η
γηραιότερη γυναίκα γιατρός στον κόσµο, έζησε
κατά την διάρκεια της 4ης δυναστείας.
THE PREPARATION OF THE MUMMY FOR THE NEXT
LIFE (DEPICTION ON PAPYRUS)
ΠΡΟΕΤΟΙΜΑΣΙΑ ΤΗΣ «ΜΟΥΜΙΑΣ» ΓΙΑ ΤΗΝ ΑΛΛΗ ΖΩΗ
(ΑΠΕΙΚΟΝΙΣΗ ΣΕ ΠΑΠΥΡΟ)
These ideas were shared by all populations in
ancient times. For example in ancient Egypt Isis
was thought to be the healing god, in ancient
Greece Asclepion, and for the Phoenicians it was
Esmun.
Imhotep, the most famous physician in Egypt
was an astronomer and an architect as well.
Imhotep was worshipped as the god of Healing
and medicine. His statue stands today in the Hall
of Immortals at the International College of
Surgeons in Chicago. Peseshet was the earliest
female physician in the world, practicing during the
4th dynasty.
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Η Ιατρικη Επιστηµη Μεσα Απο Τους
Παπυρους
Τα περισσότερα που γνωρίζουµε για την
ιατρική επιστήµη στην αρχαία Αίγυπτο
προέρχονται από ντοκουµέντα που έχουν γράψει
οι γιατροί-ιερείς.
Αυτά τα ντοκουµέντα βασίζονται σε
προϊστορικές πρακτικές. Οι αποκρυπτογραφήσεις
των παπύρων µας δείχνουν ότι οι Αιγύπτιοι
γνώριζαν πολλά για την ιατρική. Μας
πληροφορούν για τις θεωρίες κάποιων ασθενειών,
ενώ πραγµατοποιούσαν επεµβάσεις για να
αφαιρέσουν κύστεις και όγκους.
Πολλές από τις πρακτικές που
χρησιµοποιούσαν οι Αιγύπτιοι τις ακολουθούµε κι
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εµείς σήµερα. π.χ.
απευθείας πίεση πάνω
στο τραύµα ώστε να
σταµατήσει
η
αιµορραγία.
Ο
παλαιότερος
πάπυρος που έχει
ανακαλυφθεί µέχρι
σήµερα είναι ο πάπυρος
THE PREPARATION OF THE MUMMY FOR THE NEXT LIFE (DEPICTION ON PAPYRUS)
τ
ο υ
K a h u n ,
ΠΡΟΕΤΟΙΜΑΣΙΑ ΤΗΣ «ΜΟΥΜΙΑΣ» ΓΙΑ ΤΗΝ ΑΛΛΗ ΖΩΗ (ΑΠΕΙΚΟΝΙΣΗ ΣΕ ΠΑΠΥΡΟ)
χρονολογείται το 1852
π.Χ.
Αναφέρεται
σε
µεθόδους
και διαγνώσεις
Medical Papyruses
αναπαραγωγής, εγκυµοσύνης, για το φύλο του
Most of what we nowadays know about
εµβρύου, για οδοντιατρικά προβλήµατα κατά την
Egyptian medicine comes from a variety of
διάρκεια της κύησης, σε γυναικείες ασθένειες, σε
medical documents written by these physicianσυνδυασµούς φαρµάκων για την αντιµετώπιση
priests. These documents are based on prehistoric
τους, σε κρέµες για κολπικές χρήσεις.
practices. The deciphering of these papyruses
Οι γνωστότεροι πάπυροι είναι του: Edwin
shows us that the Egyptians knew a lot about
Smith, χρονολογείται το 1600 π.Χ. και του Ebers,
medicine. They inform us of treatments to
χρονολογείται το 3000 π.Χ.
diseases and how they performed surgical
operations to remove cysts and cancer.
Ο πάπυρος του Edwin Smith έχει µήκος 5 µ.
Many of the ancient procedures the Egyptians
Περιγράφει
48 χειρουργικές περιπτώσεις
used are still in use today. For example: using
τραυµάτων του κεφαλιού, του λαιµού, των ώµων
pressure directly on the wound to stop the
και του θώρακα. Φαίνεται πως υπήρχε µια
bleeding.
τεράστια εµπειρία σε σπασίµατα η οποία
The oldest as yet discovered papyrus is the
αποκτήθηκε σε έναν τόπο όπου τα ατυχήµατα
Kahun Gynaecology Papyrus, dated back to 1825
ήταν υπερβολικά πολυάριθµα, όπως κατά την
BC. It describes methods of diagnosing
διάρκεια
του
pregnancy, diagnosing sex of the fetus, toothache
χτισίµατος
των
problems during pregnancy, gynaecological
πυραµίδων.
illnesses and the combination of drugs to cure
Ο πάπυρος του
them such as pastes and vaginal applications.
Eber είναι ένα
The most famous papyruses are the Edwin
τεράστιο
ρολό
Smith Papyrus (1600 BC) and the Ebers Papyrus
µήκους 20m και
(3000 BC). The Edwin Smith Papyrus is 5
πλάτους
30cm.
meters long. It describes 48 surgical cases of
Περιγράφει
head, neck, shoulder, breast and chest wounds. It
BRAIN REMOVAL THROUGH
παθήσεις
των
contains a vast experience in fractures that can
THE NOSE BEFORE
µατιών,
του
only be acquired at a site where accidents are
MUMMIFICATION
δέρµατος,
των AΦΑΙΡΕΣΗ ΕΓΚΕΦΑΛΟΥ
extremely common such as during the building of
ΤΗ ΜΥΤΗ ΠΡΙΝ ΤΗ
ά κ ρ ω ν , ΑΠΟ
the pyramids.
ΜΟΥΜΙΟΠΟΙΗΣΗ
γυναικολογικές και
The Ebers Papyrus is a huge roll, more than
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ορισµένες χειρουργικές
20 meters long and 30 cm
επεµβάσεις. Συµπεριλαµβάνει
wide. It describes diseases of
ανατοµική και φυσιολογική
the eye, skin, extremities,
ορολογία.
gynaecology and some surgical
Απαριθµεί για αυτές τις
diseases.
παθήσεις 877 ιατρικές
Anatomical
and
συνταγές και 400 φάρµακα.
physiological terminology are
Οι αρχαίοι Αιγύπτιοι
also included. For the treatment
µελέτησαν την ανατοµία του
of these diseases, 877 recipes
κεφαλιού και του εγκεφάλου.
and 400 drugs were described.
The ancient Egyptians had
Στον πάπυρο του Eber
also studied the anatomy of the
περιγράφεται µε ακρίβεια η
THE SO CALLED CANOPIC VESSELS WHERE θέση
της καρδιάς και
head and the brain.
THE INNER ORGANS WERE PLACED BEFORE
α
ν
α
φ
έ
ρ
ονται ορισµένες
The Ebers Papyrus
MUMMIFICATION
TΑ
ΛΕΓΟΜΕΝΑ
ΚΑΝΩΠΙΚΑ
ΑΓΓΕΙΑ
ΟΠΟΥ
διαταραχές της, όπως οι
precisely describes the position
ΤΟΠΟΘΕΤΟΥΣΑΝ ΤΟ ΚΑΘΕΝΑ ΑΠΟ ΤΑ
of the heart and illustrates some ΕΣΩΤΕΡΙΚΑ
πτώσεις
ΟΡΓΑΝΑ ΤΟΥ ΝΕΚΡΟΥ ΠΡΙΝ ΤΗ
of its disorders such as dropped
τ ω ν
ΜΟΥΜΙΟΠΟΙΗΣΗ
heart beats. They also knew
παλµών.
that blood supply runs from the heart to all organs
Γνώριζαν την κυκλοφορία
of the body. Due to the examination of the
του αίµατος, κι ότι η καρδιά
embalming bodies we can conclude that they also
προµηθεύει το αίµα σ’ όλα
knew about tuberculosis, arteriosclerosis, measles,
τα όργανα του σώµατος.
arthritis, epilepsy, tumors, headaches, stomach
Από την εξέταση των
upsets, skin diseases, leprosy and pneumonia.
ταριχευµένων σωµάτων
Drugs of different sources were used. Mineral,
συµπεραίνουµε ότι γνώριζαν
as zinc was used especially in eye and skin
την φυµατίωση, την
ointments. Animal products, as ox meat, liver as
αρτηριοσκλήρωση, την
well as more than 160 plants (many still in use)
ευλογιά, τα αρθριτικά, την
were used in the form of pills, powders or
επιληψία, τους όγκους, τους
suppositories.
πονοκεφάλους,
τις
Among the common plants used were
στοµαχικές διαταραχές, τις
sycamore, castor oil, acacia gum, mint, garlic and
δερµατικές παθήσεις, τη
onion. Yeast was used for indigestion and
λέπρα και την πνευµονία.
externally for leg ulcers. The dosage was adjusted
Χρησιµοποιούσαν
to the patients' age. They also used alternative
διαφορετικά φάρµακα όπως
medicine like physiotherapy, heliotherapy,
µέταλλα π.χ.
hydrotherapy. In the Kalup Papyrus treatments
τον ψευδάργυρο στις
with mud and clay are described.
αλοιφές για τα µάτια και το
δέρµα, ζωικά προϊόντα, όπως
AN EGYPTIAN
MUMMY
βοδινό κρέας, συκώτι και
Mummification
ΜΙΑ ΑΙΓΥΠΤΙΑΚΗ
The Egyptians knew the human anatomy and
περισσότερα από 160 φυτά
ΜΟΥΜΙΑ
healing very well mostly due to the extensive
(πολλά από τα οποία
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mummification ceremonies. These involved
removing most of the internal organs including
the brain, lungs, pancreas, liver, spleen, heart and
intestine.
The Mummification process was 70 days
long. During this period the body was treated by
THE WRAPPING OF THE BODY ‘TILL THE
CREATION OF THE MUMMY
ΤΟ ΤΥΛΙΓΜΑ ΤΟΥ ΣΩΜΑΤΟΣ ΜΕΧΡΙ ΤΗ
∆ΗΜΙΟΥΡΓΙΑ ΤΗΣ ΜΟΥΜΙΑΣ
priests and experts. The Mummification
laboratory was called The house of energy. The
definition of the word embalming means give
back the full health. The last words of the
ceremony go back to life, go
back to life forever, to be
young again forever.
χρησιµοποιούνται και σήµερα).
Τα χρησιµοποιούσαν ως χάπια, σκόνες και
υπόθετα.
Ανάµεσα στα πιο συνηθισµένα φυτά ήταν η
συκοµουριά, το ρετσινόλαδο, κόµµι ακακίας,
µέντα, σκόρδο και κρεµµύδια.
Τη µαγιά την χρησιµοποιούσαν για την
δυσπεψία και τις εξωτερικές πληγές των ποδιών.
Η δοσολογία ήταν προσαρµοσµένη στην ηλικία
του ασθενούς.
Χρησιµοποιούσαν και τις εναλλακτικές
θεραπείες όπως φυσιοθεραπεία, ηλιοθεραπεία,
υδροθεραπεία. Στον πάπυρο του Kalup
αναφέρονται θεραπείες µε λάσπη και πηλό.
Μουµιοποιηση
Οι Αιγύπτιοι γνώριζαν πολύ καλά την
ανατοµία του ανθρώπινου σώµατος και θεραπείας
του χάρη στις εκτεταµένες τελετές της
µουµιοποίησης.
Πραγµατοποιούσαν περίπλοκες αφαιρέσεις
των εσωτερικών οργάνων συµπεριλαµβανοµένων
του εγκεφάλου, των πνευµόνων, του παγκρέατος,
του συκωτιού, της σπλήνας, της καρδιάς και των
εντέρων.
Η διαδικασία της µουµιοποίησης διαρκούσε
70 ηµέρες. Σ’ αυτό το διάστηµα το σώµα
αναλάµβαναν ιερείς και τεχνικοί. Το εργαστήρι
της µουµιοποίησης ονοµαζόταν Το σπίτι της
Ζωτικότητας.
Η τελευταία φράση της τελετής ήταν
Ξαναζείς, ξαναζείς για πάντα, να είσαι πάλι νέος
για πάντα.
The role of Egyptian
Medicine in History
Egyptian physicians based
their treatments on
THE SO CALLED CANOPIC VESSELS WHERE THE
INNER ORGANS WERE PLACED
BEFORE MUMMIFICATION
TΑ ΛΕΓΟΜΕΝΑ «ΚΑΝΩΠΙΚΑ» ΑΓΓΕΙΑ ΟΠΟΥ
ΤΟΠΟΘΕΤΟΥΣΑΝ ΤΟ ΚΑΘΕΝΑ ΑΠΟ ΤΑ ΕΣΩΤΕΡΙΚΑ
ΟΡΓΑΝΑ ΤΟΥ ΝΕΚΡΟΥ ΠΡΙΝ ΤΗ ΜΟΥΜΙΟΠΟΙΗΣΗ
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THE BODY AFTER THE REMOVAL OF THE ORGANS
TO ΣΩΜΑ ΜΕΤΑ ΤΗΝ ΑΦΑΙΡΕΣΗ ΤΩΝ ΟΡΓΑΝΩΝ
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examination, followed by diagnosis. Descriptions of
the examination the most demanding part of a
physician’s job, was lengthier both than the
diagnosis and the recommended treatment.
Ancient Egyptian pharmacopoeia and many
medical practices were ineffective, if not downright
poisonous: e.g. excrement used in medicines would
only in the rarest of cases prove to be wholesome,
and if applied as wound dressing it may cause
tetanus poisoning, yet dung continued to be used in
Europe until the Middle Ages.
The reliance on magic and faith surely retarded
the development of more rational views of the
causes of diseases and their cures.
Egyptian theories and practices influenced the
Greek, who passed on information to many of the
physicians in the Roman Empire and through them
Arab and European medical thinking for centuries to
come.
Bibliography
Λαοί της Ανατολής, Βασίλης Κυριακίδης, εκδ. Β.
Κυριακίδης, 2001;
Κρανιοεγκεφαλικές κακώσεις σε ενήλικες,
Συγκούνας. Aθήνα, 1996;
∆ιαδίκτυο: Η ιατρική στην Αίγυπτο;
www.nea-acropoli.gr
Ο Ρολος Της Αιγυπτιακης Ιατρικης Στην
Ιστορια
Οι Αιγύπτιοι γιατροί είχαν ως βάση της
θεραπείας τους την εξέταση και ύστερα
ακολουθούσε η διάγνωση.Η αρχαία αιγυπτιακή
φαρµακολογία και πολλές ιατρικές πρακτικές
ήταν αναποτελεσµατικές, εάν όχι ολοφάνερα
δηλητηριάσεις π.χ.
τα περιττώµατα σε σπάνιες περιπτώσεις
µπορούν να είναι ωφέλιµα και εάν επαλειφθούν
πάνω σε τραύµατα µπορεί να προκαλέσουν
τέτανο.
Η κοπριά συνεχίστηκε να χρησιµοποιείται
στην Ευρώπη µέχρι το Μεσαίωνα. Η
εµπιστοσύνη στη µαγεία και την πίστη, πρέπει να
επηρέασε την εξέλιξη για πιο δραστικές
θεραπείες ή τις αιτίες που προκαλούν τις
ασθένειες. Οι αιγυπτιακές θεωρίες και πρακτικές
επηρέασαν τους Έλληνες, οι οποίοι εφοδίασαν
µε πληροφορίες τους γιατρούς της Ρωµαϊκής
Αυτοκρατορίας και διαµέσου αυτών τους
Άραβες και την Ευρωπαϊκή ιατρική σκέψη για
τους µελλοντικούς αιώνες.
Iconography
www.ancientegypt.co.uk/mummies/story/
main.html
THE MUMMIFICATION PROCESS
∆ΙΑ∆ΙΚΑΣΙΑ ΜΟΥΜΙΟΠΟΙΗΣΗΣ
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Claudio Arena
Liceo Statale “Enrico Boggio Lera”
Via Vittorio Emanuele 346, Catania, Italy
www.liceoboggiolera.it
[email protected]
BLACK HOLES
I BUCHI NERI
The term Black Hole has only recently been
coined. It was first used in 1969 by the physicist
John Wheeler and described effectively a twocentury old idea.
The studies began in 1783, when John Mitchell,
one of the great forgotten scientists of the XVIII
century published an essay in The Philosophical
transactions of the Royal Society of London where
he stated that a star with a large mass and density
would present such a gravity as to prevent light
from getting out. A beam of light emitted from the
surface of this star would be drawn back by the
star gravitational attraction. Mitchell understood
that a great lot of stars with such characteristics
could exist. His great intuition was to imagine that
the light leaves a star as we consider it a rocket
leaving the surface of the planet. To completely
escape Earth’s gravitational attraction and travel
through space, a rocket needs a 11/Km/sec velocity
n upwards, that is to say, more than the terrestrial
gravity attracts it downwards. Mitchell knew
nothing about rockets on the moon but he did know
that, theoretically a largest star could exert a
gravitational attraction such as to swallow the
light rays that travel at the speed of 300,000 Km/s.
John Mitchell calculated that in a celestial a body
with a big mass the gravity would be such as to
prevent light to escape from its surface, and
theorized that an object with the bigger mass than
the universe could be invisible. In 1795, the great
French mathematician Pierre Simon de Laplace
calculated that light could not have got out of quite
massive bodies, the dark bodies as he called them.
However, it was only in 1939 that scientists found
out that Black Holes could really exist, and in the
atomic era it finally became known how a black
hole is formed. In 1939 J. Robert Oppenheimer
and a student of his, Hartland Snyder, showed that
a cold, big mass star is bound to collapse
indefinitely, thus becoming a Black Hole.
Oppenheimer and Snyder’s work, which came out
almost contemporarily to Oppenheimer-Volkoff’s
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REPRESENTATION OF A BLACK HOLE
RAPPRESENTAZIONE DI UN BUCO NERO
Il termine buco nero (black hole) è stato coniato solo di recente. Esso fu creato nel 1969 dal
fisico John Wheeler. Questo termine descriveva
efficacemente un’idea di almeno due secoli prima. Gli studi sui buchi neri ebbero inizio nel
1783, quando John Michell, uno dei grandi
scienziati dimenticati del XVIII secolo, pubblicò
nelle Philosophical transactions of the Royal
37
MAIN PHASES OF STAR EVOLUTION
FASI PRINCIPALI DELL’EVOLUZIONE STELLARE
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IMAGE OF THE DUST DISC SURROUNDING THE BLACK
HOLE INSIDE THE SPIRAL GALAXY NGC 4261
IMMAGINE DEL DISCO DI POLVERE ATTORNO AL BUCO
NERO (CENTRO DELLA GALASSIA A SPIRALE NGC 4261)
about neutron stars, drew the same conclusions:
black holes could exist. They could be real objects,
not only mathematic games of people sharing an
interest in Einstein’s theory. In the Sixties, when
Einstein’s theory of general relativity came back
in fashion, black holes were thoroughly studied and
their features clarified in detail. Furthermore, in the
mid-sixties, scientists calculated that there can’t be
stable dead stars bigger than three solar masses and
as we commonly observe stars (not yet collapsed)
which have much bigger masses, astrophysicists
have taken into serious consideration the idea that
black holes are scattered about in the cosmic space.
To completely understand how a black hole is
generated, men have had to wait and live the atomic
era, when scientists began to comprehend what
happens inside a star. A star is composed of three
main parts: the visible surface, called photosphere,
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Society of London un saggio in cui precisava che
una stella di massa e densità abbastanza grandi
avrebbe avuto una gravità tale che la luce non
avrebbe potuto uscirne. Un raggio di luce emesso
dalla superficie della stella sarebbe stato trascinato all’indietro dall’attrazione gravitazionale
della stella. Michell capì che poteva esistere un
gran numero di stelle con queste caratteristiche.
La sua grande intuizione fu quella di immaginare
la luce che lascia una stella simile a un razzo che
lascia la terra. Per sfuggire completamente
all’attrazione gravitazionale terrestre e viaggiare nello spazio un razzo ha bisogno di una velocità verso l’alto di 11 km/s, cioè superiore alla
forza con cui la gravità lo attrae verso il basso.
Michel non sapeva nulla di razzi sulla luna, ma
sapeva che in teoria una stella molto grande poteva avere un’attrazione gravitazionale tale da
inghiottire i raggi luminosi che viaggiano alla
velocità di 300.000 km/s. John Michel calcolò
che in un corpo con una massa molto grande la
gravità sarebbe tale da impedire alla luce di sfuggire dalla sua superficie e ipotizzò che l’oggetto
con la massa più grande dell’universo potrebbe
essere invisibile. Nel 1795, il grande matematico
francese Pierre Simon de Laplace calcolò che la
luce non avrebbe potuto uscire da corpi abbastanza massicci, che chiamò corpi oscuri.
38
BLACK HOLE IN M87
BUCO NERO IN M87
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Ma si dovette attendere fino al 1939 per provare che i buchi neri potrebbero esistere nella
realtà, e l’era atomica per capire bene qual’e il
meccanismo alla base della loro formazione.
Nel 1939 J: Robert Oppenheimer e un suo
studente, Hartland Snyder, mostrarono che una
stella fredda e di grande massa deve collassare
indefinitamente, diventando un buco nero. il lavoro di Oppenheimer-Snyder, che apparve quasi
contemporaneamente all’articolo di Oppenheimer-Volkoff sulle stelle di neutroni, raggiungeva le stesse conclusioni: i buchi neri potevano
REPRESENTATION OF A GALAXY
esistere. Potevano essere oggetti reali, non solo
CONTAINING A BLACK HOLE
giochi matematici di persone che si interessavano
RAPPRESENTAZIONE DI UNA GALASSIA
alla teoria di Einstein. Negli anni Sessanta,
CONTENENTE UN BUCO NERO
quando la teoria della relatività generale di Einstein tornò di moda, i buchi neri furono intensicounterbalance the mass gravitational push and
vamente studiati e furono chiarite in dettaglio le
carries out this task exerting a pressure. A star can
loro proprietà. Inoltre nella metà degli anni Sesrealize such pressure
through the
santa gli scienziati calcolarono che non si possonucleus’contorsion: the gas is compressed, heats up
no avere stelle morte stabili maggiori di tre masse
and generates enough pressure to sustain itself.
solari
e dato che si osservano comunemente stelThis contraction, however, would provide a star
le (non ancora collassate) con masse molto più
with energy for only 15 million years, whereas we
grandi, gli astrofisici hanno preso in seria consiknow that the Sun is 4.57 billion years old.
derazione l’idea che buchi neri si trovino sparsi
Therefore, there must be another source of
nel cielo.
pressure: this source is the thermonuclear fusion.
Ma per comprendere appieno come si possa
In a star like the Sun, thermonuclear fusion
formare un buco nero si deve attendere l’era
reaction occurs between two atoms of hydrogen
atomica, periodo in cui si cominciò a capire methat generate one of helium. When hydrogen is
glio quello che accade all’interno di una stella.
over, a star begins to contract. If, during the
Una stella è formata da tre parti principali:la
contraction temperatures of 108 K are reached, the
superficie visibile, chiamata fotosfera;un invireaction of fusion occurs between the Helium
luppo gassoso contenente la maggior parte della
atoms. As helium fuses, it produces Carbon and
massa; un piccolo nucleo centrale. Il nucleo deve
Oxygen, Carbon fuses into Neon and Magnesium;
combattere la spinta gravitazionale
Oxygen into Silicium and Sulfur and Neon,
dell’inviluppo. E svolge questo compito eserciMagnesium, Sulfur and the rest fuse into a series of
tando una pressione. Una
reactions (so far only partly
stella può ottenere questa
understood) to generate Iron.
pressione dalla compressioFrom iron no other reaction
ne del nucleo:il gas viene
takes place, and so the nucleus
compresso, si riscalda e gestarts to contract. If the star is
nera pressione sufficiente a
less than 1.5 solar masses big,
sostenersi. Ma la contrazio(one and a half the sun mass)
ne darebbe energia a una
the matter density itself
SPACE-TIME CURVATURE
stella come il sole solo per
generates enough pressure to
CURVATURA DELLO SPAZIO-TEMPO
a gas mass
containing
most of the
star
mass,
and a small
c e n t r a l
nucleus. The
nucleus has
t
o
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sustain the star (degenerating pressure). A white
dwarf is born, a super dense star, not bigger than our
earth. One of the first dwarfs to be discovered was
the one which orbits around Sirius, the brightest
star in the sky, a winter sky colossus called Sirius
B. This star concentrates a mass close to that of the
Sun in a volume nearly equal to the earth’s. It is
then extremely dense. One has to imagine that a box
of matches full of solar matter would weigh 15
grams, while filled with Sirius B matter would have
a weight of 10 tons if it were on the Earth. Instead,
if the star features more than 1.5 the solar mass, the
degenerating pressure is no more sufficient. The
neutrons collapse onto the nucleus and the star
becomes a super dense star with a mass equal to the
sun enclosed in a sphere with a 20 Km diameter,
about the size of New York. There, the matter
collapses and becomes so dense that the quantity of
matter equal to 1/100th of a pin-head would weigh as
much as 24 elephants. A neutron star is born. Yet,
if the star features more than 3 solar masses, the
collapse is inevitable. The mass of the star gets
concentrated in an infinitely small as well as
infinitely dense point. Gravity is so high it doesn’t
FROM LEFT: WILLIAM HAWKING, MARTIN REES,
MICHEAL GRIFFIN (NASA ADMINISTRATOR)
DA SINISTRA: WILLIAM HAWKING, MARTIN REES, MI-
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15 milioni di anni, mentre il sole ha circa 4,57
miliardi di anni. Ci deve essere quindi un'altra
fonte di pressione: questa fonte si chiama fusione
termonucleare.
In una stella come il sole la reazione di fusione termonucleare avviene tra due atomi di idrogeno che ne formano uno di elio.
Quando finisce l’idrogeno la stella inizia a
contrarsi. Se nella contrazione si raggiungono
temperature di 108 K si innesca la reazione di fusione tra atomi di Elio. L’Elio fondendo genera
Carbonio e Ossigeno, il Carbonio fonde in Neon e Magnesio; l’Ossigeno in Silicio e Zolfo, e
Neon, Magnesio, Zolfo e il resto fondono in una
serie di reazioni (capite solo in parte) per formare
Ferro. Dal Ferro non avviene più nessuna reazione. E così il nucleo inizia a contrarsi. Se la
stella ha meno di 1,5 masse solari (una volta e
mezzo la massa del sole) la stessa densità della
materia genera pressione in grado di sostenere la
stella (pressione di degenerazione). È nata una
nana bianca, una stella super densa, non più
grande della terra. Una delle prime nane bianche scoperte è stata quella che orbita attorno a
Sirio, la stella più luminosa del cielo, colosso del
cielo invernale, Sirio B. Questa stella concentra
una massa vicina a quella del sole in un volume
vicino a quello della terra. È così molto denso.
Basti pensare che una scatola di fiammiferi piena
di materia solare peserebbe 15 grammi, mentre
riempita di materia di Sirio B peserebbe 10 tonnellate, se fosse collocata qui sulla terra. Se la
stella ha invece più di 1,5 masse solari la pressione di degenerazione non è più sufficiente. I
neutroni collassano sul nucleo e la stella diventa
una stella superdensa con la massa del sole racchiusa in una sfera di 20 km di diametro, circa la
città di New York. Lì la materia collassa e diventa così densa che una parte di materia grande
1/100 di una capocchia di spillo peserebbe quanto
24 elefanti. È nata una stella di neutroni. Ma se
la stella ha più di 3 masse solari il collasso è inevitabile. La massa della stella viene concentrata
in un punto infinitamente piccolo e infinitamente
denso. La gravità è così forte da non fare uscire
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A GALACTIC BLACK HOLE (REPRESENTATION)
UN BUCO NERO GALATTICO
(RAPPRESENTAZIONE ARTISTICA)
even let the light out; that’s why it looks black: only
a black hole is visible in space. However, how a
black hole may show up all its power is a matter
which Professor William Hawking is closely
concerned with. Born exactly 300 years after Galileo
Galilei’s death, Hawking has the same
professorship as Isaac Newton at Cambridge
University. Hawking’s mind moves freely not in
Newton’s universe, but in Einsteins’s one. We are
used to thinking about gravity – Hawking says – as
a force which attracts objects to the earth and the
earth to the Sun, but Einstein had the great idea of
considering gravity as an effect of the space and
time curvature in presence of very big bodies.
Einstein understood that nothing can exist in a
certain space without existing in a certain time
simultaneously. Space and time are linked together
to form the flexible frame dimensional structure of
the universe: the so-called space-time. Space-time
is almost impossible to imagine because our sensory
universe is limited to our everyday three-dimension
experience. The best way for us to get into
Einstein’s universe is to imagine that space and
time are like an elastic plan. If space-time were
empty, the plan would have absolutely no reliefs, but
big bodies like the earth and the sun bend the
elastic surface of space-time producing a curve. This
curvature represents Einstein’s concept of gravity.
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nemmeno la luce. Per questo appare nera: si vede
solo un buco nero nello spazio.
Ma come può manifestarsi un buco nero in
tutta la sua potenza è una questione che viene studiata approfonditamente dal professor William
Hawking.
Nato esattamente 300 anni dopo la morte di
Galileo, Hawking occupa la stessa cattedra di
Newton alla Cambridge University. La mente di
Hawking si muove liberamente non nell’universo
di Newton, ma in quello di Albert Einstein. Abbiamo l’abitudine di considerare - dice Hawking
- la gravità come una forza che attrae gli oggetti
verso la terra e questa verso il sole ma Einstein
ha avuto la brillante idea di considerare la gravità come un effetto della curvatura dello spazio
e del tempo in presenza di corpi molto grandi;
egli ha compreso che niente può esistere in un
certo spazio senza esistere contemporaneamente
in un determinato tempo.
La spazio e il tempo sono legati insieme a
formare la flessibile struttura quadro dimensionale dell’universo: il cosi detto spazio-tempo. Lo
spazio-tempo è quasi impossibile da immaginare,
poiché il nostro universo sensoriale è limitato
alle tre dimensioni dell’esperienza quotidiana. Per
noi il modo più semplice di entrare nell’universo
di Einstein è
di immaginare
che lo spazio
e il tempo
siano come un
piano elastico.
Se lo spaziotempo fosse
vuoto il piano
sarebbe assolutamente privo di rilievi,
ma
corpi
molto grandi
come la terra
e il sole pieREPRESENTATION OF THE GRO
J1677-40 BINARY SYSTEM
gano la superRAPPRESENTAZIONE DEL SISTEMA
ficie elastica
BINARIO GRO J1677-40
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The bigger is the mass of a star or a planet, the
deeper is the curvature of space-time around it and
consequently the bigger is its gravity. Imagine to
launch onto a plan something extremely heavy like a
star collapsing on itself and you will find a universe
full of holes. While a giant star gets cold as long as
it implodes, it bends the space-time around itself
more and more. When it reaches a particular critical
mass, it will literally create a black hole in the
space-time. Objects can precipitate into it but can
never get out of it. One of the most brilliant experts
of black holes, Phil Charles, looks for them. Phil
has found strong signals that show the presence of a
black hole in a not far area of our galaxy. As he
points out, looking for these objects is an
extraordinary way of get ting closer to the borders of
modern physics. By day Phil Charles holds lessons
of theoretical astrophysics at Oxford university
and by night he passes from theory to practice
looking for black holes with the biggest telescopes
STARS EVOLUTION
EVOLUZIONE STELLARE
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REPRESENTATION OF BINARY SYSTEM M33 X-7
RAPPRESENTAZIONE DEL
dello spazio-tempo incurvandola. Questa curvatura è il concetto einsteiniano di gravità. Maggiore è la massa di una stella o di un pianeta, più
grande è la curvatura dello spazio tempo attorno
a essi, e maggiore è quindi la loro gravità.
Si immagini di lanciare su piano qualcosa di
estremamente pesante come una stella che collassa su se stessa e vi troverete un universo pieno di
buchi. Quando una stella gigantesca si raffredda
man mano che implode piega sempre di più lo
spazio-tempo intorno a sé. Quando raggiungerà
un a certa massa critica creerà letteralmente un
buco nero nello spazio-tempo. Gli oggetti possono precipitare in esso, ma è impossibile che riescano ad uscirne. Phil Charles, uno dei maggiori
studiosi di buchi neri, si dedica a dar loro la caccia. Phil ha trovato forti segnali che indicano la
presenza di un buco nero in un’area non lontana
della nostra galassia. Come lui stesso dice, cercare questi corpi è un modo straordinario per avvicinarsi ai confini della fisica moderna. Di giorno
Phil Charles tiene lezioni di astrofisica teorica
alla Oxford University e di notte passa dalla teo-
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on the Earth: Las Palmas and Hawaii in the north
hemisphere, in South Africa, Chile and Australia in
the southern one. The searchers of black holes
exploit the best instruments to peruse the deep space
looking for these mysterious objects: from the x-ray
satellites and the orbited telescope Hubble, to the
best optical or radio-wave telescopes on earth.
Black holes cannot be seen by definition since light
can’t get out of them. Official science accepted the
idea that black holes could exist only in the 90s.
Theory tells us that inside black holes all that man
knows about the universe and its laws is no longer
worth. When a great star dies, it will by all means
create a black hole. But how can you possible find
an invisible object which may be located hundreds
of light years away? With more stars in the sky than
sand grains in all the world’s beaches, how is it
possible to spot a small black star that swallows
light instead of shining like a lighthouse at night?
Astronomers do not properly look for black holes,
but for the effects they provoke in the surrounding
space. Astronomers look for a visible star which
may have remained trapped in a black hole’s orbit
but this too is not easy to recognize. It is like
looking for a needle in a haystack, with the
difference that if the needle is not felt there is no
hope of finding it. In the 80s the Japanese made a
big step ahead in this field by launching the x-ray
satellite Ginga, provided with a device able to spot
any source of x rays in the universe. In practice, it
is x-rays which inform us of the presence of a black
hole. In 1989, the satellite Ginga recorded a sudden
increase of x-rays in an area not distant from our
galaxy. The source of radiation was an invisible
object 3,000 light years away around which there
seemed to rotate a scarcely brilliant star. Such star
SIZE OF THE STARS
DIMENSIONI DELLE STELLE
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ria alla pratica cercando buchi neri dai
più grandi telescopi
della terra: Las palma
e
Hawaii
nell’emisfero settentrionale, in Sudafrica,
in Cile e in Australia.
I cercatori di buchi
SIRIUS A AND SIRIUS B
neri utilizzano gli
strumenti migliori per scrutare lo spazio profondo
alla ricerca di questi oggetti misteriosi: dai satelliti a raggi x e dal telescopio Hubble in orbita ai
migliori telescopi ottici e a onde radio sulla terra. I buchi neri per la loro stessa natura non possono essere visti, poiché la luce non riesce a uscirvi. La scienza ufficiale ha accettato l’idea che
i buchi neri possono effettivamente esistere solo
negli anni Novanta. La teoria ci insegna che
all’interno dei buchi neri tutto ciò che sappiamo
dell’universo e delle sue leggi non ha più valore.
Quando una grande stella muore dovrà per
forza dare luogo a un buco nero. Ma come si fa a
trovare un oggetto invisibile che potrebbe trovarsi
a centinaia di migliaia di anni luce di distanza?
Con più stelle nel cielo che granelli di sabbia in
tutte le spiagge del mondo, come è possibile trovare una piccola stella nera che inghiotte la luce
invece di brillare come un faro nella notte? Gli
astronomi non cercano propriamente i buchi neri, ma gli effetti che essi provocano nello spazio
circostante. Gli astronomi cercano una stella visibile che può essere rimasta intrappolata
nell’orbita di un buco nero ma anche queste non
sono facili da riconoscere. È come cercare un ago
in un pagliaio, con la differenza che se l’ago non
si fa sentire non c’è speranza di trovarlo. Fondamentale fu il lancio negli anni Ottanta da parte
dei giapponesi del satellite a raggi x Ginga, dotato di uno strumento in grado di individuare qualunque sorgente di raggi x nell’universo. Sono in
pratica i raggi x a informarci della presenza di un
buco nero. Nel 1989 il satellite Ginga registrò un
improvviso aumento dei raggi x in una regione
non lontana della nostra galassia. La sorgente
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had been classified as Cygnus v404. It was exactly
the star the astronomers were looking for. The
hypothesis is that the invisible object is a black hole
originated from a star, the most common type.
According to the theory a black hole like this
should have a mass equal to ten of our sun, but with
a diameter equal to the city of London. A second
type of black holes is less common, being these far
bigger than the previous ones, located in the middle
of galaxies. A matching analogy of what occurs to
Cygnus v404 is with a well built man and a very
thin woman. While they rotate, the man hardly shifts
whereas the woman counterbalances their weights
and moves much faster. Calculations demonstrate
that Cygnus v404 completes a total orbit around its
partner once every 6.5 days. In order to gain such a
high speed, it has to rotate around a body with a
remarkable gravitational mass. It has been
calculated that the mass of Cygnus v404’s
mysterious partner equals four times that of the sun.
This means that it is noticeably heavier, as related to
theoretical calculations, than a neutron star.
Almost surely it is a black hole. This black hole is
CYGNUS X-1 (X RAY)
CIGNO X-1 (RAGGI X)
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BINARY SYSTEM
SISTEMA BINARIO
della radiazione era un oggetto invisibile a 3.000
anni luce di distanza dalla terra attorno al quale
sembrava ruotare una stella poco luminosa. La
stella era stata catalogata come cigno v404.
Era proprio la stella che gli astronomi cercavano. L’ipotesi è che l’oggetto invisibile sia un
buco nero di origine stellare, il tipo più comune.
In base alla teoria un buco nero di questo tipo
dovrebbe avere una massa pari a dieci volte quella del nostro sole, ma con il diametro della città di
Londra.
Meno comune è un secondo tipo di buchi neri, molto più grandi dei precedenti, che si annidano al centro delle galassie. Un’eccellente analogia di quello che succede a cigno v404 è quella di
un uomo robusto e di una donna molto gracile.
Mentre roteano l’uomo a mala pena si sposta,
mentre la donna per bilanciare i loro pesi si sposta
molto di più. I calcoli dimostrano che v400 compie un’orbita completa attorno al suo partner misterioso una volta ogni sei giorni e mezzo.
Per raggiungere una velocità così alta deve
ruotare attorno ad un corpo con una massa gravitazionale notevole. È stato calcolato che la massa
del partner misterioso di v404 è pari a quattro
volte quella del sole. Ciò significa che è notevolmente più pesante, rispetto a calcoli teorici, di una
stella a neutroni. Quasi certamente è un buco
nero. Questo buco nero sta guidando v404 in una
danza fatale sottraendo gas alla sfortunata stella
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REPRESENTATION OF THE
CYGNUS X-1 BINARY SYSTEM
RAPPRESENTAZIONE DEL
SISTEMA BINARIO CIGNO X-1
per alimentare un grande disco di materia. Queste particelle, avanzando a spirale verso il buco
nero, si scaldano e inviano un ultimo segnale a
raggi x al mondo esterno. In modo analogo sono
stati identificati dagli astronomi una decina di oggetti simili. Uno dei primi fu cigno x1.
Su quest’oggetto K. S. Thorne e Stephen
William Hawking hanno fatto una scommessa:
cigno x1 è un buco nero? William Hawking aveva scommesso di no. Come lui stesso dicequesto non vuol dire che non credevo ai buchi
neri. È che avevo bisogno di una sorta di polizza
assicurativa. Avevo dedicato molto lavoro ai buchi neri e sarebbe stato solo tempo perso se si
fosse scoperto che non esistevano. Almeno avrei
avuto la consolazione di vincere la scommessa.quando nel 1974 Hawking e Thorne fecero la
scommessa non c’erano prove consistenti, ma col
passare degli anni le prove divennero più convincenti e Hawking dovette così pagare la scommessa. Come racconta lo stesso Thorne, nel 1990
Hawking si trovava a Los Angeles e venne nel
mio ufficio a fare varie copie di quello che avevo
vinto si trattava dell’abbonamento per un anno
a Penthouse, con grande disgusto della moglie come racconta Hawking. Questa scommessa
scritta a mano su un foglio di carta, è divenuta il
simbolo del primo riconoscimento dell’esistenza
dei buchi neri da parte della comunità scientifica.
driving v404 into a fatal ballet, subtracting gas from
the unlucky star to feed a big disc of matter. While
advancing spirally towards the black hole, these
particles heat up and send a last x-ray signal to the
external world. By the same token the astronomers
have spotted about ten similar objects. One of the
first was cygnus x1. On this object K. S. Thorne
and Stephen William Hawking made a bet: is
cygnus x1 a black hole? William Hawking had bet
it wasn’t. As he points out – this does not mean I
did not believe in black holes. It’s just I needed
some sort of insurance policy. I had worked a lot
on black holes and it would
have only been a waste of
time had we found out they
did not exist. I would at
least have had the
consolation to win the bet.
When, back in 1974,
Hawking and Thorne made
the bet, there were no
positive proofs but as time
went by proofs became
more convincing and
Hawking had to pay the
BINARY SYSTEM WITH FORMATION OF A
BLACK HOLE
bet. As Thorne himself
SISTEMA
BINARIO
CON FORMAZIONE DI UN
recounts, in 1990 Hawking
BUCO NERO
was in Los Angeles and
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Un articolo pubblicato
su Nature il 20 ottobre
rivela che è stato scoperto
un buco nero, nella Galassia del Triangolo
(chiamata anche M33 e
distante da noi circa tre
milioni di anni luce) che
orbita intorno a una stella,
con un periodo di tre giorni e mezzo. La particolarità di questo corpo
(catalogato col nome M33
X-7) è di essere estrema-
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History of
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came to my
office to make
some copies of
what I had won,
the
yearly
subscription to
Penthouse, with
his wife’s great
disappointment
–as
Hawking
says. This handwritten bet on a
paper
sheet,
b
e
c
a
m
e
the
GALAXY WITH A BLACK HOLE
symbol of the
GALASSIA CON BUCO NERO
f i r s t
acknowledgement of the existence of black holes by
the scientific community. An article published on
Nature on October 20th reveals that a black hole
had been discovered, in the Triangle Galaxy, (also
called M33, about 3 million light years far from
earth) which orbited around a star with a 3.5 days’
period. The peculiarity of this body (catalogued as
M33 X-7) is that it is extremely massive: it is
thought to have a mass 15.65 times as much as the
sun’s, being so the most massive as yet observed
black hole, and also its partner has a quite high
mass value (about seventy times as much as our
Sun’s). Jeffrey McClintock of HarvardSmithsonian Center for Astrophysics of
Cambridge, has explained that it is an enormous
star that has an enormous black hole as partner.
At the end the partner will become a supernova: so
there will be a couple of black holes. The data
obtained through observations, however, is in
contrast with today’s theories concerning black
holes, and so Jerome Orosz, of San Diego State
University, one of the article’s authors, has
maintained that it is this discovery that arouses all
sorts of questions about the possibile origins of
such a black hole. In fact, a black hole is born from
the collapse of a massive star but, in the case of a
binary star system, the star with a bigger mass
collapses first and turns into a black hole. This did
not happen with M33 X-7, because the star which
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mente massiccio: si calcola che abbia una massa
pari a 15,65 volte quella del Sole, rendendolo così
il buco nero più massiccio finora osservato, e
anche la sua compagna ha un valore della massa
molto elevato (circa settanta volte la massa del
Sole). Jeffrey Mc Clintock dell’HarvardSmithsonian Center for Astrophysics di Cambridge, ha spiegato che Si tratta di un’enorme stella
che ha come compagno un enorme buco nero.
Alla fine, la compagna diventerà una
supernova: si avrà così una coppia di buchi neri.
I dati ottenuti dalle osservazioni, però, sono in
contrasto con le teorie attuali riguardo ai buchi
neri, e perciò Jerome Orosz della San Diego
State University, uno degli autori dell'articolo, ha
affermato che è questa scoperta a far sorgere ogni sorta di domanda circa le possibili origini di
un simile buco nero. Infatti, un buco nero nasce
dal collasso di una stella massiccia, ma, nel caso
di un sistema binario di stelle, collassa per prima
in un buco nero la stella avente la massa maggiore.
Ciò non è successo nel caso di M33 X-7, poiché la stella che ha poi dato origine al buco nero
aveva una massa minore della sua compagna. Inoltre, la stella genitrice avrebbe dovuto anche
avere un raggio molto maggiore, superiore addirittura alla distanza attuale dei due corpi celesti,
tale che le due stelle avrebbero dovuto condividere parte della loro atmosfera. Sulla base delle
conoscenze attuali, questa condizione non dovrebbe permettere di dare vita a un buco nero di
massa così elevata, a causa della perdita di materiale gassoso. Lo studio del buco nero appena
scoperto potrebbe portare a nuove conoscenze
sull'origine dei buchi neri e della loro evoluzione
e alla revisione delle teorie attuali.
Forse non troveremo mai le risposte, ma almeno sappiamo dove cercarle.
Iconography
www.scienzaonline.com/astronomia/img/
nascita-buco-nero3g.jpg, scienza online, Guido Donati
www.gsfc.nasa.gov/gsfc/spacesci/pictures/
46
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gave origin to the black hole had a smaller mass
than its partner. Furthermore, the generating star
should also have had a much bigger radius, even
superior to the actual distance between the two
celestial bodies, such that the two stars would have
had to share part of each other’s atmosphere. On
the basis of our present knowledge, this status is not
likely to give life to such a big-massed black hole,
owing to the loss of gas matter. The study of the
newly discovered black hole might bring new
information about the origin of black holes and
their evolution or to reviewing our current theories.
Maybe no answers will be given, but at least we
shall know where to find them
Bibliography
Hawking W. Stephen, Dal big bang ai buchi neri,
Rizzoli, Milano, 1988;
Hawking W. Stephen, Inizio del tempo e fine della
fisica, Mondadori, Milano, 1992;
Hawking W. Stephen, Buchi neri e universi neonati,
Rizzoli, Milano, 1995;
Hawking W. Stephen & Roger Penrose, La natura
dello spazio e del tempo, Sansoni, Milano,
1996;
Kaufmann J. Williams, Le nuove frontiere
dell’astronomia, Sansoni, Firenze, 1980;
Shipmen B. Harry, Buchi neri, Quasar e universo,
Zanichelli, Bologna, 1982;
www.pd.astro.it/MOSTRA/NEW/
A3003EVO.HTM, INAF istituto nazionale di
astrofisica, Renato Falomo, Daniela Fantinel;
www.esa.int/SPECIALS/Missione_Possibile/
SEMOEJD3M5E_0.html, ESA European
space agency, Fulvio Drigani;
www-groups.dcs.st-and.ac.uk/~history/
Biographies/Newton.html, School of
Mathematical and Computational
Sciences;University of St Andrews, John J
O'Connor e Edmund F Robertson;
www.jpl.nasa.gov/news/news.cfm?release=2007122, NASA, Brian Dunbar;
www.pd.astro.it/MOSTRA/NEW/
A5022RAD.HTM, INAF istituto nazionale di
astrofisica, Renato Falomo, Daniela Fantinel;
epm
blackhole/BH1m.jpg, NASA, Brian Dunbar;
www.pd.astro.it/MOSTRA/NEW/IMAGES/
BHOLE1.JPG, osservatorio astronomico di
Padova, Renato Falomo;
www.astrosurf.com/cosmoweb/documenti/
buchineri.html,astro surf;
www.lastronomia.it/News2006/07-2006.htm,
L’astronomia, M. Ferrara, F. Oldani, R. Serpilli;
www.ivreastrofili.it/Astrofisica/Testi/
Relativit%E0%20generale.htm,gruppo astrofili Eporediesi
www.nasa.gov/images/
content/163830main_Hawking_Griffin_Rees
.jpg, NASA, Brian Dunbar;
http://diamante.uniroma3.it/hipparcos/
BlackHole.jpg, Università degli studi di Roma,
Joram Marino;
www.scienzagiovane.unibo.it/mortestelle/
neri.html, Università di Bologna, R. Giacomelli. B. Poli;
http://chandra.harvard.edu/photo/2007/
m33x7/m33x7.jpg, osservatorio astronomico di
Roma, Marco Castellani;
www.pd.astro.it/MOSTRA/
IMAGES/120702.JPG, osservatorio astronomico di Padova, Renato Falomo
http://astrolink.mclink.it/ids/lib/nanabi.htm,
Astro-link, Stefano Iacus;
www.astrosurf.com/cosmoweb/stelle/
evoluzione.html, astro surf;
www.castfvg.it/zzz/ids/steneutr.html, circolo
astrofili talmassons, Lucio Furlanetto;
www.pd.astro.it/MOSTRA/NEW/
EVOL.HTM#stelle6, osservatorio astronomico di Padova, Renato Falomo;
www.bo.astro.it/sait/spigolature/
spigo101base.html, osservatorio astrofisica di
Bologna, Marco Lolli;
www.torinoscienza.it/dossier/apri?
obj_id=8864, Torino scienza, Patrizia Picchi,
http://diva.mporzio.astro.it/webdiva/News/
news_universo_nov.htm, osservatorio astronomico di Roma, Francesco D’Alessio.
47
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What is What in Astronomy?
1. Earth
2. Jupiter
3. First step
4. Galaxy of Andromeda
5. Hubble
6. Mars
7. Sputnik
8. Omega Centauri
B
A
9. Saturn
10. Solar System
11. Moon
12. Sun
C
D
E
F
G
H
I
J
K
L
1-G, 2-D, 3-F, 4-I, 5-H, 6-L, 7-C, 8-K, 9-J, 10-B, 11-E, 12-A
CREATED FOR YOU
BY
Vangelis Voultsinos
Experimental High School of University of Macedonia, Thessaloniki, Greece
[email protected]
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19
Manuele Gangi
Liceo Statale “Enrico Boggio Lera”
Via Vittorio Emanuele 346, Catania, Italy
www.liceoboggiolera.it
[email protected]
ECLIPSE: A MYSTERY IN
THE ANCIENT TIMES
ECLISSI: UN MISTERO
NELL’ANTICHITÀ
The sun has always been
Il sole è stato sempre consideconsidered very important for
rato molto importante per la vita
earthly life because it gives us
terrena perché ci dà calore, luce
heat, light and, in a certain
e, in un certo senso, anche prosense, even protection. Our life
tezione. La nostra vita non ci
would not exist without the sun.
sarebbe senza sole. Possiamo
We are certainly able to
ben capire, quindi, cosa succeunderstand, therefore, what
deva nelle popolazioni antiche
happened in the ancient
quando il sole, per motivi allora
populations when the sun,
sconosciuti e misteriosi, scomECLIPSE IN KAYSERI
owing to unknown and
pariva nel bel mezzo del giorno.
ECLISSI A KAYSERI
mysterious reasons for those
Anche oggi un’eclissi totale di
times, disappeared in the middle of the day. Even sole dà delle emozioni molto forti. Io ho avuto la
today a total eclipse of sun stirs up some very fortuna di assistere a questo evento nel marzo del
strong emotions. I was lucky enough to witness this 2006 in Turchia, in occasione di un Meeting di Eevent in March 2006 in Turkey, on the occasion of PMagazine e devo dire che è stata una delle più bela Meeting of EPMagazine and I must say that it has le esperienze che io abbia mai avuto. Infatti, nel giro
been one of the most beautiful experiences I have di pochi minuti tutto è diventato buio, la temperatuever had. In fact, within a few minutes, everything ra è scesa moltissimo e un leggero vento è comparso
became dark, temperature fell down many degrees all’improvviso. Non solo mi sono reso conto di
and a light wind suddenly appeared. I not only quanto siamo infinitamente piccoli rispetto alla
realized how infinitely
grandezza dell’universo,
small we are in
ma anche di come
comparison with the
quest’ultimo sia veramenbigness of the universe
te dinamico. Il primo pobut even how the latter
polo che decise di regiis really dynamic. The
strare questo meravigliofirst people that decided
so evento fu la Cina. Il 22
to record this marvellous
ottobre del 2134 a.C.
event were Chinese. On
scrissero che Il Sole e la
22nd October 2134 B.C.
luna non si incontrarono
in armonia.
they wrote, in fact, that
Da questo possiamo
The Sun and the moon
capire che videro l’evento
did not meet in
MAP OF KAISERI ECLIPSE
come un qualcosa di cataharmony. From this we
MAPPA ECLISSE KAYSERI
strofico, di estremamente
can understand that they
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49
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saw the event like
negativo. Questo è ansomething catastrophic
che dimostrato dal fatand extremely negative.
to che due astronomi,
This is also proved by
Hi e Ho, furono messi
the fact that two
a morte perché non
astronomers, Hi and
riuscirono a prevedere
Ho, were put to death
l’evento: Qui giacciobecause they didn't
no i corpi di Hi e Ho,
succeed in foreseeing
il cui fato, benché trithe event: Here lie the
ste, è risibile; uccisi
bodies of Hi and Ho,
perché non poterono
whose fate, although
scorgere l’eclissi che
fu invisibile.
sad, is laughable;
Un'altra testimokilled because they
nianza ci arriva
could not perceive the
dall’antico poeta greco
eclipse that was
invisible. Another A 1888 IMAGE OF AN ECLIPSE OF THE SUN AND THE MOON Archiloco che con poECLISSI DI SOLE E DI LUNA IN UNA RIPRODUZIONE DEL 1888
chi versi riuscì a detestimony arrives from
the ancient Greek poet Archiloco who with a few scrivere, verso la metà del VII secolo a.C., lo stralines succeeded in describing, about the half of the ordinario fenomeno dell’eclisse: Non c’è nulla di
VII century B.C., the extraordinary phenomenon of incredibile, nulla di innegabile, nulla di assurdo,
the eclipse: there is nothing unbelievable, nothing poiché Zeus padre degli Olimpi fece notte a mezzoundeniable, nothing absurd, since Zeus father of giorno, e del sole splendente smorzò ogni luce. Un
the Olimpis turned midday into night and damped freddo timore calò sugli uomini. Inoltre, in molte
every light of a shining sun. A cold fear fell on occasioni, le eclissi turbarono così tanto l’animo
men. Besides, in a lot of occasions, eclipses have so dell’uomo da far riappacificare intere popolazioni.
much disturbed man's mind
Un esempio eclatante ci
as to make entire
arriva dallo storico Erodoto che narra di una guerra
populations be reconciled.
fra i Lidi e i Medi, due poAn impressive example
poli che combatterono inarrives from the historian
cessantemente per cinque
Herodotus that narrates
anni senza arrivare a nessun
about a war between the
Lydians and the Medes,
accordo.
two people that fought
Lo storico infatti scrive
che Mentre essi con pari
incessantly for five years
without coming to an
fortuna proseguivano la
agreement. The historian in
guerra, nel sesto anno si
fact, writes that While they
scontrarono e, nel corso
della battaglia, il giorno
continued the war with
ECLIPSE IN PROJECTION
all'improvviso diventò notequal fortune, in the sixth
ECLISSI IN PROIEZIONE
te... I Lidi e i Medi cessayear they clashed and,
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during the battle, unexpectedly the day became rono allora il combattimento e s'adoprarono ennight... The Lydians and the Medes then stopped trambi affinché si facesse fra loro la pace. Questo
the fight and they both did their best to make a dir poco originale episodio è molto significativo
peace. This original episode is very meaningful perché ci fa capire ancor di più quanto la potenza e
because it makes us understand even better, how the il mistero di eventi naturali avesse influenza sulle
power and the mystery of inexplicable natural popolazioni.
Inoltre l’uomo cercò anche di contrastare questo
phenomena had their influence on populations.
Hence people tried to oppose this appalling terrificante fenomeno, sviluppando dei rituali caratphenomenon developing some characteristic rituals teristici per ogni cultura che ancora oggi in alcune
for every culture, which still today in some parts of parti nel mondo vengono svolti. Per esempio gli anthe world take place. For example the ancient tichi cinesi pensavano che l’eclissi era causata da un
Chinese, since they thought the eclipse to be caused drago che divorava il sole e per questo cercavano di
by a dragon that devoured the sun, tried to send it scacciarlo e spaventarlo percuotendo tamburi e faaway and to frighten it making a lot of noise playing cendo vibrare nel cielo migliaia di frecce. In Giapdrums and having thousand of arrows vibrate in the pone invece la popolazione copriva i pozzi per evisky. In Japan, the population covered the wells to tare che il veleno proveniente dal cielo oscurato poavoid the poison coming from the darkened sky. tesse inquinare l’acqua e provocare quindi un danno
This could pollute water provoking therefore a ancora più grande. Ci furono anche delle credenze e
greater damage. There were also some positive spiegazioni positive riguardo le eclissi. Per esempio
beliefs and explanations as concerning the eclipses. alcune antiche tribù eschimesi pensavano che il
For example some ancient Eschimo tribes think sole e la luna lasciassero il loro posto in cielo per
that this phenomenon is due to the divine controllare che sulla terra andasse tutto bene; o anbenevolence. In fact, the sun and the moon, to cora alcune popolazioni nordiche vedevano le eclischeck that on earth everything goes well, leave their si come il congiungimento amoroso tra il sole e la
place in the sky. Eclipses were seen, even as the luna. Ma l’uomo, nel corso della storia ha cercato di
loving union between the sun and the moon. But dare una spiegazione scientifica a questo straordinario evento. Mentre inizialman, in the course of the
mente attribuiva l’eclissi a
history has also tried to
give
a
scientific
tremende punizioni degli
explanation to this
Dei o addirittura all’opera
extraordinary event. While
di draghi, molti filosofi
initially he attributed the
greci o pensatori degli
eclipse
to
awful
ultimi secoli prima di Cripunishments of gods or
sto incominciarono a proeven to dragons, many
porre alcune ipotesi. InfatGreek philosophers or
ti, riuscirono a formulare
thinkers of the last
tre principali teorie:
centuries before Christ
• la prima individuava
began to propose some
come causa la luna, che
new hypotheses. In fact,
interponendosi tra la terra
SUN ECLIPSE
they succeeded in
e il sole impediva ai raggi
ECLISSI DI SOLE
formulating three principal
solari di raggiungere il
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theories on the origin of
the solar eclipse:
• the first one
identifies as a cause the
moon that, interposing
between the earth and
the sun, prevents the
solar rays from reaching
our planet leaving it in
the dark;
• the second one
identifies, instead, as a
cause some clouds
JOHANNES KEPLER
present in the universe
containing elements that would prevent the
combustion; these clouds, would succeed in
extinguishing temporarily the sun provoking
therefore a total obscuring in proximity;
• the third theory identifies finally as a cause a
vacant celestial body in the space and able to attract
all the bright rays in one point of its surface.
But, despite this first attempt of rational
explanation,
a
n e g a t i v e
conception of the
e c l i p s e s
remained always
rooted in society,
tied up to a
divine will and
a l s o
t o
negativeness.
Particularly also
in the Middle
Ages and at the
beginning of the
modern
age
people thought
t h a t
t h e
happening of an
ANGELO SECCHI
e c l i p s e
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nostro pianeta, lasciandolo al buio;
• la seconda individuava come causa alcune nubi presenti nell’universo contenenti elementi che
avrebbero impedito la combustione; queste nubi, in
prossimità del sole, sarebbero riuscite a spegnerlo
temporaneamente provocando quindi un oscuramento totale;
• la terza teoria, infine, individuava come causa
un corpo celeste vacante nello spazio e capace di
attirare tutti i raggi luminosi in un solo punto della
sua superficie.
Ma, nonostante questo primo tentativo di spiegazione razionale, rimase sempre radicata nella società
una concezione negativa delle eclissi, legata al volere divino e anche alla negatività. In particolare anche nel medioevo e negli inizi dell’età moderna si
pensava che il
verificarsi di un
eclisse
preannunciasse delle
sventure. Ed è
solo dal XVII
secolo che si
incominciò
a
studiare questo
fenomeno mettendo da parte
miti, paure e legSOLAR CORONA
gende tramandaCORONA SOLARE
ti da secoli. In
particolare Johannes Kepler, in occasione
dell’eclissi di sole del 12 ottobre 1605 fu il primo a
descrivere l’apparizione della corona solare. Anche
l'astronomo reale inglese Edmund Halley, con
l’eclissi del 1705 riuscì a fare la stessa osservazione,
individuando anche alcune protuberanze. A partire
dalla seconda metà dell’800, grazie all’osservazione
delle eclissi si fecero importanti scoperte. Infatti, nel
1851 fu costruito il primo dagherrotipo della corona
solare e nel 1860 Angelo Secchi e Warren de la
Rue riuscirono a fotografarla. Grazie a queste ultime fu possibile dimostrare che le protuberanze non
52
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portended evils. And it is only since the XVII
century that this phenomenon has been studied,
setting apart myths, fears and legends handed down
for centuries. Particularly Johannes Kepler, on the
occasion of the eclipse of sun of October 12th 1605
was the first one to describe the apparition of the
solar crown. Also the royal English astronomer
Edmund Halley, with the eclipse of 1705
succeeded in making the same observation also
individualizing some prominences. Beginning from
the second half of 19th century, thanks to the
observation of eclipses, important discoveries were
made. In fact, in 1851 the first daguerreotype of the
solar crown was made, in 1860 Dry Angel and
Warren de the Rue took some photos of the solar
crown.
Thanks to these pictures it was possible to prove
that the prominences are not optical effects but they
are part of the solar atmosphere. Finally a new
element that was called helium was identified in the
sun. In short, even if there are still people that
sometimes elaborate absurd theories, we can say
that today the eclipse is not a mystery anymore or
an event to fear, but only a show not to be lost for
the great charm and the load of emotions that it
succeeds in transmitting in a few minutes.
Iconography
Coppermine photo gallery, http://
astroimmagini.uai.it/albums/userpics/10020/
eclisse%20sole%202006%20piccola.jpg,
07.04.2006
Jens Kleemann, www.jenskleemann.de/wissen,
Wissens-Quiz , Hamburg, 31.01.2008
John E. Huerta, www.sil.si.edu/digitalcollections/
hst/scientific-identity/fullsize/SIL14-S00305a.jpg, General Counsel Smithsonian
Institution, Washington, 22.07.2003
R. Baglioni, www.astro.unifi.it/gruppi/plasmi/
ricerca/eit_171.gif, Dipartimento di Astronomia
e Scienza dello Spazio, Firenze, 22.01.2008
Tomaso Belloni, www.brera.inaf.it/hevelius/
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sono effetti ottici,
ma fanno parte
dell’atmosfera
solare. Infine, si
riuscì a individuare nel sole un
nuovo elemento
che fu chiamato
Elio. Insomma
possiamo dire che
oggi l’eclisse non
è più un mistero o
un evento da teSOLAR PROMINENCE
mere, ma solo
PROTUBERANZE SOLARI
uno spettacolo da
non perdere per il grande fascino e il carico di emozioni che riesce a trasmettere in pochi minuti.
Bibliography
www.pd.astro.it/eclisse, Istituto Nazionale di Astrofisica, Padova, 26.09.2005
http://it.wikipedia.org/wiki/Eclissi_solare,
Wikimedia Foundation, Italy, 30.01.2008
Marco Maura, www.astrofilitrentini.it/attiv/
lavori/eclsol07.html, Associazione Astrofili
Trentini, Trento, 21.01.2003
Fred Espenak, http://sunearth.gsfc.nasa.gov/
eclipse/eclipse.html, NASA, USA, 15.01.2008
www.exploratorium.edu/eclipse/, 04.01.2006
Fred Espenak, www.mreclipse.com/Special/
SEprimer.html, 14.01.2008
http://csep10.phys.utk.edu/astr161/lect/time/
eclipses.html, 10.08.2000
www.bbc.co.uk/science/space/solarsystem/sun/
solareclipse.shtml, BBC, London, 01.02.2008
Mauro dolci, www.te.astro.it/infoservizi/
attivitadivulg/2005eclissesole/
eclisse_sole_05.html, Osservatorio Astronomico
Collurania, Teramo, 13.12.2007
F.R. Stephenson, www.dur.ac.uk/Classics/
histos/1998/stephenson.html, Department of
Physics, University of Durham, 21.07.1998
53
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Lenia Kokkinoun, Antonis
Varvianis, Lina Kexagia
Greek Gymnasium Lyceum of Brussels
[email protected]
FOLLOWING
GALILEO
FOOTSTEPS ...
ΑΚΟΛΟΥΘΩΝΤΑΣ
ΤΑ ΒΗΜΑΤΑ ΤΟΥ
ΓΑΛΙΛΑΙΟΥ ...
Introduction
Εισαγωγή
What is the article about?
This article is about an effort from a group of
students to reproduce in the modern school
environment some of the Free Fall experiments
that Galileo performed.
A METAL BALL’S FREE FALL FROM THE PISA TOWER
Η ΕΛΕΥΘΕΡΗ ΠΤΩΣΗ ΜΙΑΣ ΜΕΤΑΛΛΙΚΗΣ ΣΦΑΙΡΑΣ
ΑΠΟ ΤΟΝ ΠΥΡΓΟ ΤΗΣ ΠΙΖΑΣ
The motivation
When we started, we knew about Galileo two
things:
a) His attitude at the famous trial against his belief
that the earth moves around the sun and
b) The picture of him performing the Free Fall
experiments by dropping objects from the top of
the tower of Pisa.
Two years ago we were asked to create a website
as a team, for our Technology class. We had some
trouble finding a subject that would interest all three
of us. Then, out of nowhere, Galileo’s life came as
an idea. We all agreed for different reasons.
I believe we had fun studying Galileo, because
that way we didn’t only learn his science theories,
but we had the chance to think about the way he
lived, trying to prove something that later turned out
to be right. Because of this project, we have also
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Το θέµα αυτού του άρθρου?
Αυτό το άρθρο αναφέρεται στην προσπάθεια
µιας οµάδας µαθητών να πραγµατοποιήσει στο
περιβάλλον ενός σύγχρονου σχολείου µερικά από
τα πειράµατα ελεύθερης Πτώσης του Γαλιλαίου.
Το κίνητρο
Οταν αρχίσαµε ξέραµε για το Γαλιλαίο δύο
πράγµατα:
a) Τη στάση του στην γνωστή δίκη εναντίον του
επειδή υποστήριζε τη θεωρία ότι η Γη κινείται γύρω
από τον Ηλιο
b) Την εικόνα των πειραµάτων Ελεύθερης
Πτώσης από τον πύργο της Πίζας.
∆ύο χρόνια πριν, µας ζητήθηκε να κάνουµε µια
εργασία
στο
µάθηµα
της
Τεχνολογίας,
∆υσκολευτήκαµε στην αρχή να βρούµε θέµα που να
ενδιαφέρει και τους τρεις µας και ξαφνικά µας ήρθε
η ιδέα να ασχοληθούµε µε τη ζωή του Γαλιλαίου.
Συµφωνήσαµε για διαφορετικούς λόγους ο
καθένας. Περάσαµε ευχάριστα µελετώντας το
Γαλιλαίο γιατί δεν µάθαµε µόνο για τις
επιστηµονικές του θεωρίες, αλλά είχαµε την
ευκαιρία να γνωρίσουµε για τη ζωή του που την
αφιέρωσε στο να αποδείξει κάτι που αργότερα έγινα
αποδεκτό.
HALVES OF THE SAME METAL BALL FALL FREE. DO
THEY MOVE FASTER, SLOWER OR THE SAME?
∆ΥΟ ΙΣΑ ΚΟΜΜΑΤΙΑ ΤΗΣ ΜΕΤΑΛΛΙΚΗΣ ΣΦΑΙΡΑΣ
ΠΕΦΤΟΥΝ ΕΛΕΥΘΕΡΑ. ΚΙΝΟΥΝΤΑΙ ΠΙΟ ΓΡΗΓΟΡΑ,
ΠΙΟ ΑΡΓΑ, ΤΟ Ι∆ΙΟ?
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come to realize how important Galileo’s theories
have been for science.
We really enjoyed studying his life and we
enjoyed even more a Free Fall Motion experiment
that we reproduced and saw successfully.
The work
The first part of the work was to
find information about Galileo’s life
and his point of view. The work was
focused on Galileo’s efforts to find
the Free Fall motion laws.
GALILEO
ΓΑΛΙΛΑΙΟΣ
The text is short because it is a part
of a web site. In the site the portrait of
Galileo and an animation of his experiments
(according to the legend from the tower of Pisa) are
shown.
Galileo’s point of view
Even today, after his death 500 years ago,
Galileo’s theories and experiments are still taught
in schools, puzzling students and teachers.
The study of Aristotle’s theory was an
important issue in his life. He started trying to verify
with experiments the truth in it.
According to that theory the speed of a body is
the result of an action (force).
He fought for his ideas, which was really hard,
because Aristotle’s theory was considered the
absolute truth at that time.
Galileo and the Free Fall Experiments
Galileo performed his experiments using slopes.
Why not just drop objects?
In his book The Two Sciences Galileo, suggests
that:
... for a ball rolling down a ramp, the speed at
various heights is the same as the speed the ball
would have attained (much more quickly!) by just
falling vertically from its starting point to that
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Εξ αιτίας της εργασίας αυτής καταλάβαµε
επίσης πόσο σπουδαίες ήταν οι θεωρίες του για την
επιστήµη. ∆ιασκεδάσαµε µε το σχεδιασµό κι
εκτέλαση των πειραµάτων Ελεύθερης Πτώσης.
Η εργασία
Το πρώτο µέρος της εργασίες ήταν να βρούµε
πληροφορίες για τη ζωή και
την
προσωπικότητα
του
Γαλιλαίου. Το κύριο κοµµάτι
εστιαζόταν στην προσπάθεια
του Γαλιλαίου να βρεί τους
νόµους
της
Ελεύθερης
Πτώσης. Το κείµενο που
γράψαµε ήταν σύντοµο γιατί
είναι µέρος ενός δικτυακού
τόπου. Βάλαµε επίσης την
ARISTOTLE
εικόνα του Γαλιλαίου καθώς
ΑΡΙΣΤΟΤΕΛΗΣ
και µια κινούµενη εικόνα
σχετικά µε τα πειράµατα που σύµφωνα µε την
παράδοση πραγµατοποίησε στον πύργο της Πίζας
(βλ. εικόνες παρακάτω).
Η προσωπικότητα του Γαλιλαίου
Ακόµα και σήµερα 500 χρόνια µετά το θάνατό
του οι θεωρίες του Γαλιλαίου και τα πειράµατά
του διδάσκονται στα σχολεία προβληµατίζοντας
µαθητές και καθηγητές.
Η µελέτη της θεωρίας του Αριστοτέλη
αποτέλεσε σηµαντικό παράγοντα στη ζωή του.
Αρχισε, προσπαθώντας να αποδείξει την ορθότητα
της θεωρίας αυτής πειραµατικά. ∆ηλαδή ότι η
ταχύτητα που αποκτά ένα σώµα είναι αποτέλεσµα
µιας δράσης (εφαρµοζόµενης δύναµης).
Ο Γαλιλαίος αντιλήφθηκε ότι αυτή η παραδοχή
ήταν λάθος. ∆εν είναι η ταχύτητα αλλά η
επιτάχυνση που οφείλεται στην δράση (δύναµη).
Υπερασπίστηκε τις ιδέες του πράγµα πολύ
δύσκολο την εποχή εκείνη, επειδή τη θεωρία του
Αριστοτέλη θεωρούσαν τότε σαν την απόλυτη
αλήθεια.
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height. But if we make the ramp gentle enough, the
motion will be slow enough to measure.
One of the main questions was: Do different
bodies that
Fall
Free
from
the
same height
r e a c h
different
velocities?
In
an
attempt
to
A METAL BALL ROLLING DOWN THE
compare
the
RAMP AND FALLING FROM A HEIGHT H
ΜΙΑ ΜΕΤΑΛΛΙΚΗ ΣΦΑΙΡΑ ΚΥΛΑΕΙ ΣΤΟ f i n a l
ΚΕΚΛΙΜΕΝΟ ΚΑΙ ΠΕΦΤΕΙ ΑΠΟ ΥΨΟΣ H
velocities of
different bodies, Galileo let them continue their
motion falling down from the bottom of the ramp.
He thought to measure the horizontal distance
traveled instead of the final velocity (see Picture).
He found that:
The square of the Velocity is proportional to the
initial Height, no matter the mass.
Today, it is proven that:
Velocity=sqrt(2*Height_of_theSlope*g)
The horizontal distance/range of the parabolic
motion is proportional to the Velocity:
vx=Velocity*cos(angle)
x=Velocity*cos(angle)*t
The reproduction of Galileo’s
experiment
The team tried to reproduce the
experiment shown on pictures
below using two metallic cylinders
of the same volume, one solid the
other hollow; thus, the cylinders
have different mass: the solid is
heavier than the hollow.
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Ο Γαλιλαίος και τα Πειράµατα Ελεύθερης
Πτώσης
Ο Γαλιλαίος πραγµατοποίησε τα πειράµατά του
σε κεκλιµένα επίπεδα. Γιατί προτίµησε την κίνηση
σε κεκλιµένα αντί να αφήνει απλώς τα σώµατα να
πέφτουν ελεύθερα; Στο βιβλίο του «Οι δύο Νέες
Επιστήµες» ο Γαλιλαίος γράφει:
... η ταχύτητα µιας σφαίρας που κυλά σε
κεκλιµένο επίπεδο σε διάφορα ύψη, είναι η ίδια
που θα είχε (αλλά πολύ συντοµώτερα) εάν έπεφτε
κατακόρυφα από το ίδιο αρχικό ύψος. Αλλά εάν η
κλίση του επιπέδου είναι µικρή τότε η κίνηση θα
είναι αρκετά αργή ώστε να µπορέσουµε να
πάρουµε µετρήσεις.
Μία βασική ερώτηση ήταν: ∆ιαφορετικά
σώµατα που πέφτουν από το ίδιο ύψος αποκτούν
διαφορετικές ταχύτητες; Σε µια προσπάθεια να
συγκρίνει ταχύτητες, ο Γαλιλαίος αφησε σώµατα
διαφορετικής µάζας να κυλήσουν στο κεκλιµένο
επίπεδο. Στη βάση του κεκλιµένου τα σώµατα είχαν
αποκτήσει µια ταχύτητα και έπεφταν σε
παραβολικές τροχιές. Μπορούσε να µετρήσει την
οριζόντια απόσταση, που θεώρησε ότι ήταν
ανάλογη της ταχύτητας στη βάση του κεκλιµένου
(βλ. Εικόνα ). Βρήκε ότι:
Το τετράγωνο της Ταχύτητας είναι ανάλογο
του αρχικού Υψους ανεξάρτητα από τη µάζα.
Σήµερα ξέρουµε ότι:
Ταχύτητα=sqrt(2*Υψους_Κλίσης*g)
Η οριζόντια απόσταση της παραβολικής τροχιάς
είναι ανάλογη της Ταχύτητας:
vx=Ταχύτητα*cos(angle)
x=Ταχύτητα*cos(angle)*t
THE TWO NEW SCIENCES
ΟΙ ∆ΥΟ ΝΕΕΣ ΕΠΙΣΤΗΜΕΣ
56
Η µεταφορά των πειραµάτων
του Γαλιλαίου στο σχολικό
εργαστήριο
Η οµάδα πραγµατοποίησε τα
πειράµατα που απεικονίζονται
παρακάτω. Αφήσαµε να κυκήσουν
από το ίδιο ύψος δυό µεταλλικοί
κύλινδροι, ένα συµπαγή και ένα µη
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1. Calculated: vx=1.25 m/s, t=0.4 s x=0.5 m
Measured: x=0.39 m
δυµπαγή (κούφιο) του ίδιου όγκου και διαφορετικής
µάζας.
2. Calculated: vx=1.25 m/s, t=0.4 s x=0.5 m
Measured: x=0.35 m
1. Υπολογισµοί: vx=1.25 m/s, t=0.4 s x=0.5 m
Μέτρηση: x=0.39 m
3. Calculated: vx=1.25 m/s, t=0.4 s x=0.5 m
Measured: x=0.35 m
2. Υπολογισµοί: vx=1.25 m/s, t=0.4 s x=0.5 m
Μέτρηση: x=0.35 m
4. Calculated: vx=1.72 m/s, t=0.5 s x=0.7 m
Measured: x=0.53 m
3. Υπολογισµοί: vx=1.72 m/s, t=0.5 s x=0.7 m
Μέτρηση: x=0.48 m
Conclusion
As shown above, the horizontal distance is similar
for objects that fall from the same height, no matter
their mass. Thus:
the final Velocity at the bottom of the ramp is
similar for objects that
“fall” from the same
height h, no matter their
mass.
4. Υπολογισµοί: vx=1.72 m/s, t=0.5 s x=0.7 m
Μέτρηση: x=0.53 m
Today, it is possible to
measure the velocities
(e.g. using position
sensors).
Galileo didn’t have
the proper measuring
devices. He had to think
another way.
We followed Galileo’s
steps and proved that the
velocities are similar just
measuring the horizontal
distances x!
No fancy stuff!! No
expensive user unfriendly
meters! Galileo was really
brilliant!!! He taught us
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Συµπέρασµα
Οπως φαίνεται από τους υπολογισµούς, οι
οριζόντιες
αποστάσεις
σωµάτων που «πέφτουν»
από το ίδιο ύψος είναι
παραπλήσιες, ανεξάρτητα
1-HOLLOW CYLINDER ROLLS DOWN FROM INITIAL
από τη µάζα.
HEIGHT 8 cm
Αρα και η τελική
1-ΜΗ ΣΥΜΠΑΓΗΣ ΚΥΛΙΝ∆ΡΟΣ ΑΠΟ ΑΡΧΙΚΟ ΥΨΟΣ 8 cm
Ταχύτητα στη βάση του
κεκλιµένουείναι η ίδια για
σώµατα που «πέφτουν»
από το ίδιο ύψος h
2-SOLID CYLINDER ROLLS DOWN FROM INITIAL
ανεξάρτητα από τη µάζα
HEIGHT 8 cm
των σωµάτων.
2-ΣΥΜΠΑΓΗΣ ΚΥΛΙΝ∆ΡΟΣ ΑΠΟ ΑΡΧΙΚΟ ΥΨΟΣ 8 cm
Σήµερα µπορούµε να
µετρήσουµε τις ταχύτητες
(π.χ.
µε
αισθητήρες
θέσης). Ο Γαλιλαίος
3-HOLLOW CYLINDER ROLLS DOWN FROM INITIAL
όµως δεν είχε κατάλληλλα
HEIGHT 16 cm
3-ΜΗ ΣΥΜΠΑΓΗΣ ΚΥΛΙΝ∆ΡΟΣ ΑΠΟ ΑΡΧΙΚΟ ΥΨΟΣ 16 cm όργανα µέτρησης. Επρεπε
να σκεφτεί άλλο τρόπο.
Εµείς, ακολουθώντας τα
βήµατά του αποδείξαµε
ότι οι ταχύτητες είναι
4-SOLID CYLINDER ROLLS DOWN FROM INITIAL
ίδιες, µετρώντας µόνο την
HEIGHT 16 cm
οριζόντια απόσταση x!
4-ΣΥΜΠΑΓΗΣ ΚΥΛΙΝ∆ΡΟΣ ΑΠΟ ΑΡΧΙΚΟ ΥΨΟΣ 16 cm
∆εν χρησιµοποιήσαµε
57
epm
17
19
EPM
History of
Science and Technology
that in Science the only thing you really need is
brains!!!
The students all over the world would really
admire him if they had the chance to learn the
methods he used in his experiments!!!
Iconography
http://users.skynet.be/fb738062
http://alexis.m2osw.com/images/
galileo_person.jpg
http://academic.shu.edu/honors/aristotle.jpg
http://galileoandeinstein.physics.virginia.edu/
tns_draft/tns_title.jpg
www.tate.org.uk/shop/images/prints/stives/
david_nash.jpg
περίπλοκα, εντυπωσιακά όργανα κι όµως
αποδείξαµε κάτι σηµαντικό!
Ο Γαλιλαίος ήταν πράγµατι εκπληκτικός!!!
Μας δίδαξε ότι στις Φυσικές Επιστήµες το µόνο
που χρειάζεσαι είναι δυνατό µυαλό!!!
Οι µαθητές σε όλο τον κόσµο θα τον θαύµαζαν
περισσότερο αν είχαν την ευκαιρία να διδαχθούν τις
µεθόδους που χρησιµοποίησε για να
πραγµατοποιήσει τα πειράµατά του!!!
Bibliography
www.sec.org.za/physics/p12mAvsG.html
http://brunelleschi.imss.fi.it/catalogo/index.html
www.bbc.co.uk/history/historic_figures/
galilei_galileo.shtml
OUR CLASS
Η ΤΑΞΗ ΜΑΣ
epm
58
epm
Guidelines for Contributors
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papers as follows:
The articles must be written by pupils after their
accurate personal or group research.
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with the History of Science and Technology. Papers
may be the result of either personal research or
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14 to 16 years old authors
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Bibliography
Iconography
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We are sorry to say that contributions without a
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EPM