segunda-feira, 30 de novembro de 2009

Wave power


25% of the world’s electricity already comes from dams and rives. Now scientists are learning how to use the sea’s power, too.
What they are doing is collecting the energy contained in waves. Here is how it works.

First, water enters a special wave machine. This pushes all the air inside the machine up to the top. Then the water leaves again and pulls the air back down. This pushing and pulling makes enough energy to work an electric motor. At the moment wave machines are small and expensive.
They don’t produce much electricity, either. But in the future they will be bigger and cheaper. One day scientists think they will produce between 25% and 30% of our electricity.

Performed by: Rita Sadio
Posted by: Rui Cóias

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