CBSE Class 6 Science Chapter 15 Notes Air Around Us
Air Around Us Class 6 Notes Understanding the Lesson
1. Moving air is called wind.
2. We can’t see air but we can feel it when,
- the clothes hanging on a rope sway.
- leaves and branches of trees rustle or flutters.
- kite fly high up in the sky.
- husk from grains or sawdust and sand can be separated by winnowing.
3. Air is a gaseous substance and thus we can compress it easily.
4. The important properties of air are:
- Air is a colourless, tasteless and odourless gaseous substance.
- Air occupies space.
- Air dissolves in water.
- Air can be compressed easily.
- Air is present everywhere around us though we cannot see it.
5. Our earth is surrounded by a thin layer of air which extends up to many kilometres above the surface of the land is called
6. Air is a mixture of many gases. The major component of air is nitrogen gas. The second major component is oxygen gas.
7. Air also contains small amount of carbon dioxide gas, water vapour and some other gases like helium, argon, neon, etc.
8. Nitrogen is a colourless, tasteless, and odourless gas. It is slightly soluble in water and this gas is important for all living beings.
9. Oxygen is a colourless, tasteless and odourless gas. It is slightly soluble in water. This gas is essential for breathing (or respiration) and burning.
10. Carbon dioxide is a colourless and odourless gas. It is moderately soluble in water. Carbon dioxide is needed by plants to carry out photosynthesis. It extinguishes a burning fire.
11. Excess accumulation of carbon dioxide in a room may cause suffocation.
12. The presence of water vapour in the air is important for the water cycle in nature. Water vapour present in air rises high in the sky along with hot air, gets cooled, condenses to form clouds and then brings rain on the earth.
13. The dust particles are always present in air.
14. The sources for the dust particles are blowing of wind, traffic on the roads, dusting at home, etc.
15. Air should always be inhaled by nose instead of mouth because fine hair and mucous are present inside the nose to prevent dust particles from entering into our respiratory system.
16. Smoke is produced mainly by burning of fuels like wood, coal, kerosene, petrol and diesel, etc. It is always harmful.
17. Smoke is emitted through the exhaust pipes connected to the engines of vehicles, etc.
18. The animals living in water are called aquatic animals.
19. The plants living in water are called aquatic plants.
20. In the presence of sunlight, plants use carbon dioxide and water to make food by the process of photosynthesis and produce oxygen gas.
21. The animals and plants use oxygen from the air for respiration and give out carbon dioxide gas.
22. Air is useful for human beings in many ways:
- Air is used for breathing purpose.
- Air is used for burning fuels to make fire.
- Air also helps in the dispersal of seeds and pollens of flowers of several plants.
- Compressed air is used to fill tyres of various kinds of vehicles.
Class 6 Science Chapter 15 Notes Important Terms
Atmosphere: The envelope of air which surrounds the earth is known as atmosphere.
Carbon dioxide: Carbon dioxide is a colourless and odourless gas. Co2 is slightly soluble in water. It is the major component of air.
Oxygen: Oxygen is a colourless, tasteless and odourless gas. It is soluble in water. Oxygen gas is essential for breathing (or respiration).
Nitrogen: Nitrogen is the major component of air. It is a colourless, tasteless and odourless gas. Nitrogen is slightly soluble in water.
Smoke: Smoke consists of fine carbon particles and some gases. Smoke is produced by burning of fuels like wood, kerosene, petrol, diesel, etc. Smoke is always harmful.
Windmill: Windmill is a huge apparatus which is rotated by wind. It is used to draw water from tube wells, run flour mills and generate electricity.