Moving water is one of the most incredible forces on Earth. Just think of the power behind a tsunami or waterfall. Harnessing the power of water is nothing new. People have been using water wheels to power mills for thousands of years. Today, hydroelectric turbines provide electricity to millions of homes and businesses. With a focus on STEM topics, this book provides an in-depth look at the advances in technology that allow us to generate hydroelectricity more efficiently. Informative diagrams and age-appropriate language make it easy for students to understand this exciting early elementary science subject.