Electricity source can come from a variety of sources, such as hydroelectric power, dams, eels, generators, power plants, power strips, and wall sockets. Hydroelectric power is generated by using the energy of flowing water to turn turbines, which then generate electricity. Dams are structures built across rivers to control the flow of water and generate electricity. Eels are a type of fish that can generate electricity when stimulated. Generators are machines that convert mechanical energy into electrical energy. Power plants are large facilities that generate electricity from various sources, such as coal, natural gas, or nuclear power. Power strips are devices that allow multiple electronic devices to be plugged into one outlet. Wall sockets are outlets in walls that provide electricity to plug-in devices.