Currents
Definition: A body of water moving in a definite direction through a surrounding body of water in which there is much less movement.
Currents are caused by the gravitational pull of the moon and the sun. Interactions with other currents influence it's direction and strength. Currents can flow for large distances. Currents that are on the surface are generally driven by wind. They affect temperatures around the world. For example, the current that brings warm water to North-West Europe stops ice from forming by the shores, which would stop ships from getting to ports and leaving them.
Currents are caused by the gravitational pull of the moon and the sun. Interactions with other currents influence it's direction and strength. Currents can flow for large distances. Currents that are on the surface are generally driven by wind. They affect temperatures around the world. For example, the current that brings warm water to North-West Europe stops ice from forming by the shores, which would stop ships from getting to ports and leaving them.