General Science Question Answers Chapter 3 Class 7 Maharashtra Board

Question Answers For All Chapters – General Science Class 7

Properties of Natural Resources-Solutions

Exercise

1. Fill in the blanks with the appropriate term.

(a) The capacity of air to hold moisture depends upon the temperature of the air.

(b) Water does not have a shape but has definite volume and mass.

(c) While freezing, the temperature of water is lowered.

(d) Neutral soil has pH 7.

2. Why is it said that –

(a) Air is a homogeneous mixture of various gases?

→ Air is a uniform mixture of gases like oxygen, nitrogen, and carbon dioxide, and they cannot be separated easily.

(b) Water is a universal solvent?

→ Water can dissolve many substances like salt, sugar, and gases, making it useful for living things.

(c) There is no alternative to water for cleaning purposes?

→ Water can dissolve dirt, wash clothes, and remove germs, which makes it essential for cleaning.

3. What will happen if…

(a) The amount of water vapor in the air increases?

→ More humidity will make the air feel hot and sticky, and it may cause rainfall.

(b) Only one crop is grown repeatedly in the soil?

→ The soil will lose its nutrients, making it less fertile for future crops.

4. With whom should I pair up?

5. State whether the following statements are true or false.

(a) Sandy soil has low capacity for holding water.

→ True

(b) The substance in which a solute dissolves is called a solvent.

→ True

(c) The pressure exerted by air is called atmospheric pressure.

→ True

6. Explain the picture in your own words.

• The image shows water and ice.
• Water is in liquid form, while ice is in solid form.
• Ice floats on water because it is less dense than liquid water.

7. Write answers to the following questions.

(a) How is light scattered by air?

→ Air contains tiny dust and gas particles that spread light in different directions, making the sky look blue during the day.

(b) Explain the various properties of water.

→ Water is colorless, tasteless, and has no shape. It can dissolve many substances and change its form into ice (solid) or steam (gas).

(c) Why is the density of seawater more than that of rainwater?

→ Seawater contains dissolved salts and minerals, making it heavier and denser than pure rainwater.

(d) What is the importance of good soil structure?

→ Good soil structure helps roots get oxygen, allows water to drain properly, and improves plant growth.

(e) What are the various uses of soil?

→ Soil is used for farming, building houses, making pottery, and growing plants.

(f) What is the need and importance of soil testing from the point of view of farmers?

→ Soil testing helps farmers know nutrient levels and choose the right fertilizers for better crops.

(g) What is the importance of air in the transmission of sound?

→ Air carries sound waves, allowing us to hear voices, music, and alarms. Without air, sound cannot travel.

(h) Why should a glass bottle completely filled with water never be kept in a freezer?

→ Water expands when it freezes, so the bottle may break because ice takes up more space than liquid water.