Book cover shows a child using a tool to work on a bicycle wheel.

Simple and Complex Machines

Grade 3-4, Physical, Machines Unit
The book Simple and Complex Machines explains that machines help people do work. Machines can help make work easier, faster, and safer. The amount of work required depends on the amount of force needed and the distance to be traveled. Seven types of simple machines are described: inclined plane, wedge, screw, lever, wheel and axle, gear, and pulley. Each machine can be found in many common devices. Complex machines combine several simple machines into one new machine in order to perform specific jobs.

Book Assembly