Wednesday, April 29, 2009

Mathematics from the Greeks

Today we learned that the Greeks are responsible for much of the mathematics that we know today. Here's what we learned from Classical Kids by Laurie Carlson

Here are some of the famous Greek mathematicians.

Pythagoras:
"His followers, Pythagoreans, believed that math was the basis for all things in life. They studied a series of numbers called triangular numbers. They laid the numbers out in rows of stones and saw that they always formed triangles."



"They also discovered that there were four figures that had all sides and angles equal. They called them the Platonic bodies, after Plato (another famous thinker and teacher in Greece)." I found a template at Math is Fun to make the 5 platonic bodies: pyramid (4 sides), cube (6 sides), octahedron (8 sides), dodecahedron (12 sides), icosahedron (20 sides). I had a little trouble making the 20 sided one.


"Greek mathematicians also discovered the pengaton, a five-sided shape. That helped them make up a pentacle, which is a five-pointed star. The Pythagoreans used the pentacle as their secret sign to each other. They studied the pentacle because it could be make with a 'never-ending line. Notice that the outside of the pentacle forms a pentagon and so does the inside of the pentacle. "




Eratosthenes
Discovered prime numbers - To find prime numbers make a chart from 1-100 and cross out any numbers that can be divided evenly by 2, 3 or 5. The ones that are left are the prime numbers

Sieve of Eratosthenes

We also read the book, The Librarian Who Measured the Earth, about how Eratosthenes used geometry to estimate the circumfrance of Earth.

2 comments:

knit1kids4 said...

how cool... I'll have to show my boys this!

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