How can pulling down make something go up? How do carnival rides work? What makes the hands on a watch go around? How does pedaling a bicycle make it move? This

Springs have been used for more than 500 years as a simple machine that can make other machines work. When you open a screen door, open an umbrella, sit on a so

The 11 lessons in this module introduce students to single and compound pulleys and gear systems. Students investigate, design, and construct various pulley sys

Examines simple machines, ranging from pliers to cranes, in a book with twenty easy-to-do experiments.