What makes the foam on top of waves?

Question

You know how in the ocean there are waves.... what makes it?

Answer 1

Air mixing with the salt water will make foam.
Air mixing with fresh water doesn't, but there are all kinds of tiny molecules of salts and other minerals in the water it's not pure.
Think of blowing through a straw in a glass of milk - you get bubbles there.
The ocean wave tops are kind of like the glass of milk, the air blowing over and through the wavetops are like the straw you blow into.

Answer 2

There is a certain amount of organic content in the ocean: proteins which was off sea animals and plants. This makes the water prone to foaming. Some beer makers use a seaweed extract to give their beer a thicker, stiffer head.

Answer 3

Here is a great description!
http://www.newscientist.com/article/mg13518372.800-science-how-foam-forms-on-ocean-waves-.html

Basically, when the energy from wind overcomes the surface tension, the suspension of water forms a spray of droplets held together by surface tension. This air-water foam is a new phase of material.