Maddie's Do You Know?: Bike Chain and Tennis Ball

OBSAH

Maddie is outside being active. She uses a special camera to find out how the chain on a bicycle works to turn the wheels and how the front wheel and handlebars are used to steer. Next, Maddie visits a factory to see how rubber, collected from trees, is made into tennis balls using a series of heavy presses. A microscopic camera reveals the special material used to cover the tennis balls with a furry coat.