How can you prove that the air that is in many bodies of nature is lighter than water?

The easiest way to prove this statement is by opening a bottle of highly carbonated mineral water. What happens when you open the bottle? Air bubbles will quickly rise up and out of the bottle, and this is all due to the fact that air is lighter than water.

Another simple experiment can be done with a balloon. Inflate the balloon with air and place it on water (for example in a bathtub). What will happen? The balloon with air will float on the surface of the water. You can also remember that almost all animals with abundant wool can swim perfectly in water without any training (unlike humans). This is due to the fact that air is trapped in their hair between the hairs, and it simplifies the swimming process for animals.