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Power Stations

The Sun and Weather.

Hydroelectric, Wave and Wind Power all rely on the weather.
The original source of the weather is the Sun.

The Sun's rays hit the equator more directly than the poles.
This is why the equator is hot and the poles are cold.

Air at the equator is heated more than at the poles
and the hot air at the equator rises,
setting up convection currents from the equator to the poles.
It is these convection currents which make the wind blow.

This is not to say that the wind always blows
from the poles towards the equator.
Local currents in the air are caused
by the geography of the Earth in that region.
The direction of the wind is unpredictable on a day to day basis
but it is the heating effect of the Sun which is the origin of the wind blowing.

As the wind blows across the sea it makes waves
and the air takes up some moisture which evaporates from the sea surface.
When the air reaches land it rises and the temperature decreases.
The colder air cannot contain all the moisture and some falls as rain.
Gravity makes the rain flow into rivers and eventually back to the sea
(see the Water Cycle on the GCSE Chemistry site).

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