Communication:Technology Starters——Water Power
In the ancient time, nearly every work must be done by hands. This is very laborious. It not only takes a lot of time, but also is tiring. So people have always been thinking of inventing machines to work for them. Machines saves people a lot of trouble. They can do a lot of work both quickly and easily. But machines need energy or it can not work. There is one inexhaustible natural energy, that is the water power.
- Added：2006
- Country：France
- Duration：15
- Time of update：2011/3/11 15:03:55