All people have jobs to do. Some jobs take a lot of energy. Simple machines help people get jobs done without working too hard. There are six kinds of simple machines: inclined planes, levers, pulleys, wedges, screws, and wheels and axles.
General Note
Includes index.
Content Note
Scavenger hunt! -- Ramp it up -- Build a ramp -- Staircase -- What's the advantage? -- Trails and roads -- Runaway truck! -- Chutes and slides -- Moving water -- Funnels -- Filler up! -- Inclined planes as complex machines -- Glossary.