Imp Questions For All Chapters – General Science Class 7
Short Questions
1. What are the gases present in air?
→ Air contains nitrogen, oxygen, carbon dioxide, and other gases.
2. Why is air called a homogeneous mixture?
→ Air is a uniform mixture of gases that cannot be separated easily.
3. What is atmospheric pressure?
→ It is the pressure exerted by air on everything around us.
4. How can we prove that air has weight?
→ By inflating a balloon, we see the stick tilts, proving air has weight.
5. What is the effect of increased temperature on air pressure?
→ When air is heated, it expands and its pressure decreases.
6. Why do we see water droplets on a cold glass?
→ The water vapor in the air condenses when it touches a cold surface.
7. What is humidity?
→ Humidity is the amount of water vapor present in the air.
8. What is the unit of atmospheric pressure?
→ It is measured in Newtons per square meter.
9. How does a barometer work?
→ A barometer measures atmospheric pressure using liquid mercury or air pressure.
10. Why is water called a universal solvent?
→ Water dissolves many substances, making it the best solvent.
11. Why does ice float on water?
→ Ice is less dense than liquid water, so it floats.
12. How is soil formed?
→ Soil is formed by the breakdown of rocks over a long time.
13. Why does sandy soil hold less water?
→ Sandy soil has large particles with spaces that allow water to drain quickly.
14. Why should soil be tested before farming?
→ Soil testing helps determine nutrient levels and improve crop growth.
15. Why does seawater have more density than rainwater?
→ Seawater has dissolved salts, making it denser than rainwater.
Long Questions
1. Why is air important for life?
→ Air provides oxygen for breathing, carbon dioxide for plants, and helps in sound transmission and weather changes.
2. Why do we feel wind blowing?
→ Wind is caused by air moving from high-pressure areas to low-pressure areas due to temperature differences in the atmosphere.
3. How does air pressure help in daily life?
→ Air pressure helps in filling tires, using syringes, drinking with straws, and flying airplanes by maintaining balance.
4. How does temperature affect the density of air?
→ When air is heated, it expands and becomes lighter, reducing density, while cold air contracts and becomes denser.
5. Why does salt water make objects float more easily?
→ Saltwater is denser than freshwater, providing more upward force (buoyancy), which makes objects float easily.
6. Why do farmers need soil testing?
→ Soil testing helps farmers check nutrient levels, allowing them to add the right fertilizers for better crop production.
7. Why does water expand when it freezes?
→ Water molecules form a loose ice structure with air spaces, making ice expand and float on water.
8. What happens if air is removed from around us?
→ Without air, breathing would be impossible, sound wouldn’t travel, and Earth would have extreme temperature changes.
Leave a Reply