Using Springs (Machines Inside Machines)
By Wendy Sadler.
Description
A spring is made of some material wound around a cylinder shape. If a spring is going to be useful it needs to be made of stiff material that will keep its shape. Springs are useful because once they are made into a shape, they want to stay in that shape. - from Amzon
ISBN(s)
1410914461, 9781410914460
