Air is a mixture of many gases, pollutants, dust, and smoke. The major component of gases is nitrogen which is 78 percent, oxygen makes up about 21 percent, while only 0.6 percent of carbon dioxide is present in the air. In addition, some traces of organ neon and hydrogen are also present in the air. In this lesson, we will be studying about important question answers about the components of air,characteristics of different gases, air pollution and it’ s management.
Fill in the blanks:Answer: nitrogen
Answer: smoke
Answer: water vapour.
Answer: carbon dioxide
Answer: acid rain
1.What are the important components of air?
Answer: Nitrogen (78%), Oxygen (21%) and other gases (carbon dioxide, water vapour, helium, Ozone, hydrogen, etc.)
2.What is gaseous exchange?
Answer: Plants release oxygen after the process of making food by photosynthesis and animals use this oxygen and release carbon dioxide required for plants. This mutual process is called gaseous exchange.
3.What are ultraviolet rays? Are they useful for us?
Answer: The rays that come from sun directly are called ultraviolet rays. Ultraviolet rays can cause skin and eye diseases in animals. They also disturb the growth of plants.
4.What is air pollution?
Answer: The impurities present in air are – pollutants reduce the air quality is known as pollution. Common pollutants are carbon monoxide, carbon dioxide, dust, pollen and sulphur dioxide.
5.What are the causes of air pollution?
Answer: Vehicle smoke, dust, burning coal and other fuels, forest fire excessive burning of wood are some causes of air pollution.
6.Why is air necessary for animals?
Answer: All animals, including human beings, need air because they take oxygen from air through the process of breathing. The oxygen is used to produce energy from the food that is eaten.
7. How is nitrogen important for plants?
Answer: Nitrogen is important for plant because it is a nutrient required for the rapid growth of plants. Nitrogen help in good crop yield.
8.How is the nitrogen gets replenished in plants?
Answerp>Answer: Nitrogen found in the soil gets absorbed through roots. The atmospheric nitrogen enters the roots only when the soil is loosened.
9.What is acid rain? Why is it harmful?
Answer:Acid rain is rain that comes down to earth along with pollutants in the air. Its harmful because it reduces the fertility of soil and also damage the monuments made up of marble.
10.What is global warming? Is it good?
Answer: Due to excess of carbon dioxide, it traps the heat from sunlight causing a raise in the earth’s temperature gradually. Global warming is not good because it can lead to melting of glacier from polar regions which will cause floods.
11.Suggest some ways of reducing air pollution.
Answer:
each one of us should plant trees. Use public transport to reduce the use of private vehicles. Regular check-up of vehicles. Use of high quality fuels. Dump the garbage in a pit. Build industries far away from residence area.
12. How does planting of trees help in making air cleaner?
Answer: Planting of trees help in making air cleaner because plants use up carbon dioxide gas present in the air for producing their food using photosynthesis.
13. Air has weight’ – explain this with an experiment.
Answer: Take two balloons of the same size, and mark them as A and B and blow them to equal size. These balloons to the end of a meter scale. Move the balloons along the scale to balance the scale. Slowly allow the air from balloon A to escape. The scale becomes imbalanced when the air is released from balloon A and the side of the scale with balloon B goes down. This shows air has weight.
14.What is the normal percentage of carbon dioxide in air?
Answer:There is only 0.04% carbon dioxide in our atmospheric air, which is the least component present in air.