Wheels and Cogs

by Mandy Suhr

Published 1 December 1996
Who designed the first wheel? Why do wheels need tyres? Full simple experiments help you find the answers to these questions.

Pulleys

by Mandy Suhr

Published 9 July 2009
How can a pulley help you to lift a heavy weight? Why are two pulley wheels better than one? Full simple experiments help you find the answers to these questions.