The Difference between Tides and Currents

Many people confuse tides and water currents, but they don’t need to, because there are some very clear differences.

While both tides and currents involve moving water, the reason for that movement is what sets them apart. Tides are caused by the moon’s gravity pulling against the Earth. Water currents, while they can occur as a part of tidal movement is caused chiefly by other means.

One place where tides and currents get confused the most is with rip currents, or rip tides, two names for the same thing, though only one is technically correct. The way that most rip currents happen is when water from one place is being pulled to another. In the case of the ocean, water is pulled by the moon, either toward shore or away from it. That’s the tide. But because the water is being pulled, especially when it’s being pulled away from shore, a void is created which results in water that eddies in one circular direction or another. And it’s the eddying effect that causes the rip tide. While it may seem like the water in the ocean is moving very rapidly straight out to sea, it’s actually moving in a circular motion, out to sea, then back again in another place. The end result is a rip current, not tide, though it does happen because of the tide.

Another way to look at the differences between the two is that tides move water back or forth, that’s it. Up onto the shore, or back away from it. Currents on the other hand tend to be one directional. Water moves from this one place, to that other place. An example of this is the deep underwater current that flows out in the deep ocean. Water moves from warmer tropical parts of the planet to areas that are colder. This movement is caused both by waters natural tendency to move from warm to cold, but also because of the turning of the Earth. That movement causes water to keep on the move itself, just as it would if you were to carry a glass of water across the room.

Currents (and eddies for that matter) also occur in all other bodies of water, whereas tides do not. There are currents in every lake, river, stream or brook; even in bodies of water that seem to be sitting perfectly still, because there is always a change in temperature which always causes water to move also.