Where can you find water?
What forms of water do you see in this video?
Try our video maker at Animoto.
How does water move?
The movement of water is easy to see and explain. Think of a river. The water is simply running downhill from the mountains and high plains to lower lakes and oceans. It is pulled by gravity. There also is movement of water in the oceans, called currents. There are two main causes of ocean currents. The first is the prevailing winds, which result from the Earth's rotation and temperature differences in the Earth's atmosphere. Second, the density differences between warm and cold water and between freshwater and saltwater cause water in the ocean to rise to the top or sink to the bottom. Cold water sinks in warm water, and saltwater sinks in freshwater. This action creates vast currents when the large amount of water in the oceans is involved.