Question

How will you prove that soil contains air in it?

Answer 1

Hint:Soil composition refers to the minerals that are present in the soil and various other substances. Soil is a basic source of nutrients which is required by plants for growth. Air and water are two essential constituents present in soil which helps in photosynthesis and growth of plants.

Complete step-by-step answer:

In soil, air is present depending on the inter-soil area and water is present which tells us the retaining ability of the soil. There are different experimental proves to confirm this.
Soil containing air can be proved by the following experiment: Take a pot, put some soil in it and pour water into the soil. Observation: We observe bubbles in the soil when water is poured gently into it. Inference: The air that was trapped in the soil escaped to form bubbles.
Air bubbles that come out when soil is added to water are because of the presence of small pores in soil that contain air. When water enters these pores, air gets displaced by it. We all know that the presence of air in soil is essential for plants and the reason behind this is that the roots of plants absorb oxygen from soil for the growth of the plants. If soil lacks air, plants growing in it will ultimately die.

Additional information:

Organic matter is also present in the soil. It is primarily derived from plant tissues and contains all the necessary plant nutrients. The stable organic fraction called humus absorbs in a plant-available form which can retain all the nutrients. Organic matter remains as raw plant residues on the soil helps protect the soil from natural calamities such as drought, wind and sunlight.
Nitrogen, phosphorus and potassium are the three primary nutrients and form a trio together which is commonly known as NPK. Other nutrients such as calcium, magnesium, sulphur, iron, copper, boron, etc are also present in trace amounts as the plant requires them in less quantity.

Note:Water present in soil also has air inside it. We can prove it by another experiment such that when we take some cold water in a glass and keep it outside for a few hours on a warm day, we observe small air bubbles on the walls of the glass. This happens due to the presence of air that is dissolved in water.