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KhanhVan
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Post by KhanhVan »

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[left]http://www.phy6.org/stargaze/Sfigs/Shlfmoon.gif[/left]

[left]http://share2.esd105.wednet.edu/jmcald/ ... gleems.GIF[/left]

ARISTARCHUS OF SAMOS

Aristarchus of Samos (Approximately 300 BC) discovered a method to figure out the ratio of the distances from the Earth to the sun, and Earth to moon. Using several observations, which included the Half-Moon, Solar Eclipse, and Lunar Eclipse, he discovered a proportional relationship between the radius of the Earth and the radius of the moon. Another Greek Mathematician/Astronomer, Eratosthenes, (In the same time period) discovered a technique to find the radius of the Earth. Combining Aristarchus' work together with that of Eratosthenes, and using observations Aristarchus made about the apparent diameter of the moon, it is possible to calculate the sizes of the Earth, moon and sun, and also the distances between the Earth, moon, and sun.

Aristarchus' technique was very crude, but incredibly genius. He obviously spent many nights under the stars, studying and thinking. Despite its inaccuracy, his argument showed an incredible understanding the mathematics and astronomy. The biggest flaw in his argument was his attempt to measure the angle created between the Earth, Moon, and Sun during a half moon (<MES).




KhanhVan
Posts: 800
Joined: Sat Dec 11, 2004 6:11 am

Post by KhanhVan »

Image ARCHIMEDES Born: c. 290 BC
Birthplace: Syracuse, Sicily, Italy
Died: 211 BC
Location of death: Syracuse, Sicily, Italy
Cause of death: Murder
Greek mathematician and inventor, born at Syracuse, in Sicily. He was the son of Pheidias, an astronomer, and was on intimate terms with, if not related to, Hiero, king of Syracuse, and Gelo his son. He studied at Alexandria and doubtless met there Conon of Samos, whom he admired as a mathematician and cherished as a friend, and to whom he was in the habit of communicating his discoveries before publication. On his return to his native city he devoted himself to mathematical research

KhanhVan
Posts: 800
Joined: Sat Dec 11, 2004 6:11 am

Post by KhanhVan »

ARCHIMEDES In On the Sphere and the Cylinder, Archimedes gives the formulae for calculating the volume of a sphere and a cylinder. In Measurement of the Circle he gives an approximation of the value of with a method which will allow improved approximations. In Floating Bodies he presents what is now called "Archimedes' principle" and begins the study of hydrostatics. He writes works on two- and three-dimensional geometry, studying circles, spheres and spirals. His ideas are far ahead of his contemporaries and include applications of an early form of integration.
Image THE DEATH OF ARCHIMEDES

KhanhVan
Posts: 800
Joined: Sat Dec 11, 2004 6:11 am

Post by KhanhVan »

Image THALES 575 BC Thales was a Greek philosopher who lived between 624-546 BC. Although none of his writings survive, we have learned of his work through the writings of others.

Thales is considered the father of Greek science, mathematics, and philosophy. He is the first person to have asked questions about the nature of the universe and considered the answers without thinking of gods or demons. This was a crucial step in scientific reasoning and led to an intellectual explosion which lasted hundreds of years.

Thales also used Egyptian and Babylonian astronomical records to predict an eclipse in 585 BC.



Thales brings Babylonian mathematical knowledge to Greece. He ues geometry solve problems such as calculating the height of pyramids and the distance of ships from the shore .

KhanhVan
Posts: 800
Joined: Sat Dec 11, 2004 6:11 am

Post by KhanhVan »

Thales of Miletus
Little is known of Thales. He was born about 624 BC in Miletus, Asia Minor (now Turkey) and died about 546 BC in Miletos, Turkey

Thales of Miletus

Some impression and highlights of his life and work follow:

Thales of Miletus was the first known Greek philosopher, scientist and mathematician. Some consider him to be the teacher of of Pythagoras, though it may be only that he advised Pythagoras to travel to Egypt and Chaldea.
From Eudemus of Rhodes (fl ca. 320 B.C) we know that he studied in Egypt and brought these teachings to Greece. He is unanimously ascribed the introduction of mathematical and astronomical sciences into Greece.
He is unanimously regarded as having been unusally clever--by general agreement the first of the Seven Wise Men, a pupil of the Egyptians and the Chaldeans.
None of his writing survives; this makes it is difficult to determine his philosophy and to be certain about his mathematical discoveries.
There is, of course, the story of his successful speculation in oil presses -- as testament to his practical business acumen.
It is reported that he predicted an eclipse of the Sun on May 28, 585 BC, startling all of Ionia.
He is credited with five theorems of elementary geometry.
From W. K. C. Guthrie we have
The achievement of Thales, has been represented by historians in two entirely different lights: on the one hand, as a marvelous anticipation of modern scientific thinking, and on the other as nothing but a transparent rationalization of a myth.
According to Guthrie himself, one may say that ``ideas of Thales and other Milesians created a bridge between the two worlds-the world of myth and the world of the mind."

Thales believed that the Earth is a flat disk that floats on an endless expanse of water and all things come to be from water.

But, more preciesly, Thales and the Milesians proceeded from the assumption of a fundamental unity of all material things that is to be found behind their apparent diversity. This is the first recorded monism in history. He also regards the world as alive and thus life and matter to be inseparable. Even plants he feels have a immortal ``soul".

Being asked what was very difficult, he answered, in a famous apophthegm, "To Know Thyself." Asked what was very easy, he answered, "To give advice." To the question, what/who is God?, he answered, "That which has no beginning or no end." (The infinite!!)

So the task of the philosophers was to establish what exactly provided this unity: one said it was water; another, the Boundless; yet another, air.

Thales is believed to have been the teacher of Anaximander and he is the first natural philosopher in the Ionian (Milesian) School.

Thales is also said to have discovered a method of measuring the distance to a ship at sea.

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Five basic propositions with proofs of plane geometry are attributed to Thales.

Proposition. A circle is bisected by any diameter.
Proposition. The base angles of an isosceles triangle are equal.
Proposition. The angles between two intersecting straight lines are equal.

Proposition. Two triangles are congruent if they have two angles and the included side equal.
Proposition. An angle in a semicircle is a right angle.

Thales the Mathematician

Proposition. An angle in a semicircle is a right angle.

Proof.


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Since there was no clear theory of angles at that time this is no doubt not the proof furnished by Thales.

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KhanhVan
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Post by KhanhVan »

Archytas of Tarentum
428 BC - 347 BC
Image Archytas (428 BC - 347 BC), was a Greek philosopher, mathematician, astronomer, statesman, strategist and commander-in-chief.

Archytas was born in Tarentum, Magna Graecia (now Italy) and was the son of Mnesagoras or Histiaeus. He was taught for a while by Philolaus and he was a teacher of mathematics to Eudoxus of Cnidus. He was scientist of the Pythagorean school, famous as the intimate friend of Plato. His and Eudoxus' student was Menaechmus.

Sometimes he is believed to be the founder of mathematical mechanics.

He is also reputed to have designed and built the first artificial, self-propelled flying device, a bird-shaped model propelled by a jet of what was probably steam, said to have actually flown some 200 yards. This machine, which its inventor called The Pigeon, may have been suspended on a wire or pivot for its "flight".

According to Eutocius Archytas solved the problem of duplicating the cube in his manner with a geometric construction. Hippocrates of Chios before reduced this problem to finding mean proportionals. Archytas' theory of proportions is treated in the book VIII. of Euclid's Elements.

The Archytas curve, which he used in his solution of the doubling the cube problem, is named after him.

Archytas was drowned in the Adriatic Sea; his body lay unburied on the shore till a sailor humanely cast a handful of sand on it, otherwise he would have had to wander on this side the Styx for a hundred years, such the virtue of a little dust, munera pulveris, as Horace calls it.




KhanhVan
Posts: 800
Joined: Sat Dec 11, 2004 6:11 am

Post by KhanhVan »

About 30000 BC : Palaeolithic peoples in central Europe and France record numbers on bones

About 25000 BC : Early geometric designs used

About 4000 BC : Babylonian and Egyptian calendars in use

About 3400 BC : The first symbols for numbers , simple straight lines , are used in Egypt

About 3000 BC : Babylonian begin to use a sexagesimal number system for recording financial transactions . It is a place- value system without a zero place value

About 3000 BC : Hieroglyphic numberals in use in Egypt

KhanhVan
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Joined: Sat Dec 11, 2004 6:11 am

Post by KhanhVan »

About 3000 BC : The abacus is developed in the Middle East and in areas around the Mediterranean. A somewhat different type of abacus is used in China


About 1950 BC : Babylonians solve quadratic equations



About 1850 BC : Babylonians know Pythagoras's Theorem



About 1800 BC : Babylonians use multiplication tables
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KhanhVan
Posts: 800
Joined: Sat Dec 11, 2004 6:11 am

Post by KhanhVan »

About 1750 BC : The Babylonians solve linear and quadratic algebraic equations , compile tables of square and cube roots . They ué Pythagoras's theorem and ué mathematics to extend knowledge of astronomy .



About 1700 BC : The Rhind papyrus ( sometimes called the Ahmes papyrus ) is written . It shows that Egyptian mathematics has developed many techniques to solve problems . Multiplication is based on repeated doubling , and division uses successive halving . 3.16 is the value for " pi "




About 1000 BC : Chinese use counting boards for calculation .
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KhanhVan
Posts: 800
Joined: Sat Dec 11, 2004 6:11 am

Post by KhanhVan »

About 530 BC : Pythagoras of Samos moves to Croton in Italy and teaches mathematics , geometry , music and reincarnation


About 500 BC : Panini's work on Sanskrit grammar is the forerunner of the modern formal language theory


About 500 BC : The Babylonian sexagesimal number system is used to record and predict the positions of the Sun , Moon and planets

About 465 BC : Hippasus writes of a " sphere of 12 pentagons" , which must refer to a dodecahedron

About 450 BC :Greeks begin to use written numerals
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