They are slowed or stopped by friction. Friction is the force that slows down or stops moving objects. It occurs when two objects slide or roll across each other or when one object slides or rolls across another. If you look under a microscope, you will see that the surface of any object is not smooth. Even something that looks as smooth as a marble has tiny bumps and holes.
Friction occurs when the bumps and holes of two objects catch and rub together.
The longer the two surfaces are in contact, the greater the friction and the slower the moving object. Safety Precautions Please read and copy the safety guidelines at the beginning of this book. WHAT YOU DO You will need at least three people to do this experiment. Arrange the garden hose so that the ball will take the longest time to get from the top of the hose to the bottom. You may use your partners to create.