Pressure

According to the kinetic theory, liquids are also composed of many small particles, but in contrast to gases where the particles are very far apart, liquid particles are often touching.

Liquid water is much more dense than air, and one liter of it contains many more particles and much more mass than an equivalent volume of air. When you dive into a lake, you can feel the pressure of the water above you even if you are just a few meters below the surface because your body is supporting a lot of weight. Doubling your depth below the surface causes the pressure on your body to also double.

Fill an empty juice can with water and put two holes down one side. Place one hole near the top of the can and one near the bottom. The water coming out of the bottom hole will shoot out much further than the water escaping from the hole near the top. This is because the water at the bottom of the can is supporting the weight of the water column above it and so it is under greater pressure.