Currents

Currents are caused by several factors.  River currents and tidal currents are primarily caused by gravity.  Gravity pulls water toward the center of the earth causing water to seek its lowest possible level. Tidal currents are pulled by the gravity of Earth, the moon and the sun.

Water has mass and having mass gives it inertia.  Newton's first law of motion, often referred to as the law of enertia goes like this: An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction.

In our terms, what this means is water will not move unless some energy is applied to it (gravity).  Once it is moving it tends to have enertia and will stay moving in the direction and speed in which it was previously moving unless something changes that direction. Understanding this is important to understanding all currents.

Navigate through the articles on currents from the adjacent menu.