NCERT Revision Notes for Chapter 15 Air around Us Class 6 Science
CBSE NCERT Revision Notes1
Answer
- What is air?
- Composition of Air
- How does oxygen become available for all living beings?
- Properties of air
2
Answer
→ Air is a mixture of gases and dust particles. It is a clear gas in which living things breathe and live.
→ Air is a matter it has volume and mass. It creates atmospheric pressure.
→ In vacuum there in no air present over there.
Atmosphere: It is a thick layer of air surrounding the earth’s surface is known as atmosphere.
Wind: The moving air is known as wind.
3
Answer
→ Air contains mainly oxygen, nitrogen and remaining includes noble gases, carbon dioxide, water vapour, traces of other gases and dust particles.
→ Oxygen and nitrogen: air contains 28% oxygen and 78% nitrogen.
→ Oxygen helps in burning. It is used by living things to respire,
→ Nitrogen helps in growth of plant.
4
Answer
→ Air contains 0.003% of carbon dioxide.
→ Carbon dioxide is also produced during burning.
→ Plants and animals produce carbon dioxide during respiration.
5
Answer
→ Air contains some amounts of water vapour depends upon the weather of a place.
→ Water vapour presence is very important for water cycle in nature.
6
Answer
7
Answer
Plants
→ They use carbon dioxide of the air to make their own food by a process called photosynthesis.
Aquatic animals
→ Most aquatic animals have special organs for respiration called gills. They use oxygen from air dissolved in water.
Amphibians
→ Some amphibians like frogs, salamanders need breathing systems for both water and air.
→ Frogs have lungs to breathe air when on land. In water, frogs breathe with their moist skin.
Birds
→ They have pair of lungs with air sacs which is open all the time, because birds need high level of oxygen during flight.
Mammals
→ They breathe with the help of lungs. They take oxygen and give out carbon dioxide.