For thousands of years, humans survived without electricity. They employed fire, solar energy, water, wind, and animal power to get things done. People's lives changed dramatically when Thomas Edison and other engineering pioneers figured out how to harness the power of electricity and put it to use for just about everything in modern life. This book provides readers with a before-and-after look at the way the world has changed. Each book in the NGSS-aligned It Changed the World series introduces readers to some amazing inventions. Interesting facts and vivid photos show how these inventions changed, and continue to change, the lives of people around the world. Each book includes a glossary, comprehension questions, and an extension activity for further learning.