What is Air?

Air is the invisible mixture of gases that makes up Earth's atmosphere. It is composed of approximately 78% nitrogen, 21% oxygen, and 1% other gases such as argon, carbon dioxide, and water vapor.

Properties of Air

Air has several important properties:

• Invisible: Air cannot be seen, but its presence can be felt and its effects observed.
• Weighs: Air has weight, and it exerts pressure on everything it touches.
• Expands and Contracts: Air expands when heated and contracts when cooled.
• Supports Combustion: Oxygen in the air is necessary for combustion to occur.
• Supports Life: Oxygen in the air is essential for the survival of most living organisms.

Roles of Air

Air plays several important roles in the environment and in living organisms:

• Respiration: Air is essential for breathing and the exchange of gases in living organisms.
• Weather: Air is involved in the formation of weather patterns, including wind, clouds, and precipitation.
• Photosynthesis: Plants use carbon dioxide from the air to produce food through the process of photosynthesis.
• Transportation: Air is used for transportation by birds, insects, and other flying organisms.

Study Guide

Here are some key points to remember about air:

1. What is air composed of?
2. List the important properties of air.
3. Explain the roles of air in the environment and living organisms.

Remember, air is all around us and plays a crucial role in the functioning of our planet and the survival of living organisms!