do u know density?

Question

What role does density play in the layering of the ocean?
What factors affect density?

Answer 1

An old bloke called Archimedes was the first to work out a physical principal called "density". It's pretty easy to find out how dense a thing is - you work out the mass (weight) of the substance that would occupy a space of which you know the volume.

The easiest way to do this is to imagine a cube of water which measures a metre on each side. In the case of your question about the ocean, theres something else that is of critical importance - the following exactitude comes into play ONLY AT 21 degrees celcuis. This volume has a mass of exactly 1.00 tonnes; it's therefore said to have a density of 1.00 tonnes per cubic metre. Everything is measured against this standard. The more dense an object is, the more mass of that substance will be required to fill one cubic metre. So, the heavier something is the more dense. The cooler a volume of water, the more dense it is. It's not a great difference - it's actually only noticable by the time you're using 5 or more figures in your calculations. However, as you're looking at a couple of different densities of the same substance, such smallness is in fact relevant.

The other thing which affects the layers in the ocean is it's saline content. The cooler water has a greater density of saline and it makes the water more dense. This means that the coldest water is also the saltiest and the heaviest therefore sits on the bottom.

This action is what drives the major global ocean currents such as the gulf stream and the El Nino Southern Oscillation (ENSO) currents. The top layer of the current is closer to the warm land masses so picks up a lot of heat. As the waters flow north, the upper layers cool as they approach the Artic ice mass and sink rapidly as they cool. Reversing direction as they do so, the cooler waters are then dragged back south until the heavier salt laden water is forced up by the movement of the upper layers as well as hitting the very cold antartic layers.

Hope this helps!


Love and Light,

Jarrah