What is hydroelectric energy and how does it work?

pema href="https://theconversation.com/us/topics/curious-kids-us-74795"Curious Kids/a is a series for children of all ages. If you have a question you’d like an expert to answer, send it to a href="mailto:curiouskidsus@theconversation.com"curiouskidsus@theconversation.com/a./em/p hr blockquote pstrongWhat is hydroelectric energy and how does it work? – Luca, age 13, Boston, Massachusetts/strong/p /blockquote pIf you’ve ever observed a river rushing down a mountain or played in the waves at the beach, you’ve felt that moving water contains a lot of energy. A river can push you and your kayak downstream, sometimes very quickly, and waves crashing into you at the beach can knock you back, or even knock you over./p pThere is a a href="https://www.energy.gov/eere/water/history-hydropower"long history of harnessing the energy in the flowing waters of rivers/a to do useful work. For centuries, people used water power a href="https://thekidshouldseethis.com/post/watermill-demonstration-video-flour-water-power"to grind grain to make flour and meal/a. In modern times, people use water power to generate clean electricity to help power buildings, factories and even cars./p h2Energy in flowing waters/h2 pThe energy in these moving waters comes from gravity. As part of the Earth’s water cycle, water evaporates from the Earth’s surface or is released from plants. When the released water vapor is carried to cooler, higher altitudes like mountainous regions, it condenses into cloud droplets. When these cloud droplets become big enough, they fall from the sky as precipitation, either as a liquid (rain) or, if it is cold enough, as a solid (snow). Over land, precipitation tends to fall on high altitude areas at first./p