How will you show that air is dissolved in water?

Activity:

Aim: To show that air is dissolved in water.

Experiment: Take some water in a glass vessel or beaker. Heat it slowly on a tripod stand. Before the water begins to boil, look carefully at the inner surface of the vessel.

Observation: Tiny bubbles are seen on the inside of the beaker.

Inference: On heating, air dissolved in water escapes in the form of these bubbles. Hence, we can say that air is dissolved in water.

[Extra information: 

Air is a mixture of colorless and odorless gases. It is made up of 78 % nitrogen, 21% oxygen, and 1 % other gases and water vapor. It also contains trace amounts of carbon dioxide, neon, helium, methane, krypton, hydrogen, nitrous oxide, xenon, ozone, iodine, carbon monoxide, water vapors, and ammonia.

The percentage of oxygen dissolved in water depends upon various factors like temperature, pressure, and dissolved salts. The percentage of air that can be dissolved in water decreases with temperature and increases with pressure. As pressure increases, dissolved oxygen also increases in water.]