Pulleys and Gears (Machines in Action)

What pulls a flag up a flagpole? How does a bicycle chain help the bicycle move? What makes an escalator move? Pulleys and gears are simple machines that can be used to make other machines work. When you take an escalator, ride in a car, use a fishing rod, or wear a watch you are using pulleys and gears. Pulleys and Gears explains what these machines are and how they help you do everyday things.