The dimensions of the Earth was first measured by Greek philosopher Eratosthnes in 200 B.C. by using simple geometric methods. He dug a narrow well at Syene (now Aswan). The well would reflect the ...

Imagine a piece of string wrapped around the Earth's equator - that's about 40,000km. How much MORE string would you need for it to sit 15cm above the ground, all the way around? The important thing ...

Introduction If you wanted to measure the circumference of Earth, how long would your tape measure have to be? Would you need to walk the whole way around the world to find the answer? Do you think ...

The radius of a circle or a sphere is the distance between the center and the edge. The radius can be used to calculate a circle's diameter, area and circumference. Likewise, a sphere's volume is ...