b Write answers to the following questions in your own words. (a) How is light scatterred by the air? (b) Explain the various properties of water. (c) Why is the density of seawater more than that of rain water? (d) What is the importance of good soil structure? (e) What are the various uses of soil? (f) What is the need and importance of soil testing from the point of view of farmers? (g) What is the importance of air in transmission of sound? (h) Why should a glass bottle completely filled with water never be kept in a freezer?
Answers
Answer: 1) Light is scattered in the air by the phenomena scattering. ... Air is a mixture of gases, smoke, dust, and very fine particles. When the rays of light fall on these particles, these rays are spread/scattered in all directions.
2) The main properties of water are its polarity, cohesion, adhesion, surface tension, high specific heat, and evaporative cooling. A water molecule is slightly charged on both ends. This is because oxygen is more electronegative than hydrogen. ... The stream of water bends due to the polarity of water molecules
3) Sea water has more density than rain water because it contains salt ions. These salt ions make the seawater heavier, which means the mass of the water increases due to the presence of salt ions.
4) A good soil structure is important to allow air and water into the soil which are vital for healthy plant growth. It will improve drainage and reduce soil erosion caused by excess surface run-off. Without structure, soils will suffer from anaerobism, waterlogging and nutrient lock-up and, ultimately, plants will die!
5) The plants that are grown in soil can be used for food, clothing, recreation, aesthetics, building materials, medicines, etc.
Soil has vital nutrients for plants.
Soil is an important part of the building process.
Clay soil is used in making pottery.
Soil is used in wastewater treatment plants.
6) Soil testing analyses is important for farmers to better understand their soil types and deficient of nutrients and it help to minimise the quantity and different types of fertilisers, it become cost benefit to peasants.
7) Since air acts as a medium of propagation for sound waves, we can say that without air the sound waves do not get transferred from one corner of the room to the other.
8) A freezer lowers down the temperature due to which substance can get cold. So, whenever a glass bottle completely filled with water is kept in a freezer the water inside the bottle becomes cool and after attaining a certain temperature it starts expanding. When it is expanded sufficiently the water bottle may burst.