Includes index.

What are machines? -- How do machines help people at home? -- How do refrigerators keep food cold? -- How do digital cameras work? -- How do video games work? -- How do machines keep people safe? -- How do machines help people work? -- How do metal detectors work? -- How does an elevator work? -- What do generators do? -- How is remote control used? -- How do robots take jobs away from people? -- How do computers help people work faster? -- How do machines move people? -- What is the difference between a gasoline engine and a diesel engine? -- What is a jet engine? -- How do machines hurt the environment? -- What impact do cars have on the environment? -- How do machines keep people healthy? -- How do people take photographs of bones? -- Careers with machines -- Young scientists at work -- Take a machines survey.