How does Hydro-Electric Power Work?

Answer 1

Falling water is used to turn a turbine, which turns a metal shaft in an electric generator, which produces electricity

Why are you talking about spelt, hardy wheat grown mostly in Europe?

Falling water causes a turbine to spin, causing a generator to spin, generating electric power. The higher or bigger the dam, the more power produced for a given water drop. And also, I'm a biscuit.

Answer 2

it uses kinetic energy (energy from fast moving things) to power homes and countries.

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I think the questioner had guessed that! More usefully, hydro-electric power uses water trapped by a dam to create a constant, usually high, "head" above the turbines. The water is piped through control-valves to turbines, rotating them hence spinning the alternators connected to them. The alternators, like those in any power-station, spin wire coils across a magnetic field to induce an electric current in the coils. The electricity leaves the alternator at high current but modest voltage, so is converted by a transformer to very high voltage for grid transmission at low current. (A 132kV line voltage can transmit 1.32MW of power at only 10A, neglecting losses which are minimised anyway by using low currents.) At the other "end", more Transformers drop the volts to those required by the user: 230V in British & European homes, 110V in the USA.