English Medium Class 9 - CBSE Question Bank Solutions for Science

Explain why steel is used to make railway lines.

Write notes on plants and animals as sources of food.

Define matter. Give four examples of matter.

Define matter. Give four examples of matter.

What are the characteristics of matter?

What are the characteristics of matter?

What is Brownian motion? Draw a diagram to show the movement of a particle (like a pollen grain during Brownian motion.

What is Brownian motion? Draw a diagram to show the movement of a particle (like a pollen grain during Brownian motion.

In a beam of sunlight entering a room, we can sometimes see dust particles moving in a haphazard way in the air. Why do these dust particles move?

In a beam of sunlight entering a room, we can sometimes see dust particles moving in a haphazard way in the air. Why do these dust particles move?

When a crystal of potassium permanganate is placed at the bottom of water in a beaker, the water in the whole beaker turns purple on its own, even without stirring. This is an example of :

When a crystal of potassium permanganate is placed at the bottom of water in a beaker, the water in the whole beaker turns purple on its own, even without stirring. This is an example of :

The best evidence for the existence and movement of particles in liquids was provided by :

The best evidence for the existence and movement of particles in liquids was provided by :

Bromine and air take about 15 minutes to diffuse completely but bromine diffuses into a vacuum very rapidly. Why is this so?

Bromine and air take about 15 minutes to diffuse completely but bromine diffuses into a vacuum very rapidly. Why is this so?

Explain why, osmosis can be considered to be a special kind of diffusion. Classify the following into

(i) osmosis, and (ii) diffusion  :

1. swelling up of a raisin on keeping in water
2. spreading of virus on sneezing
3. earthworm dying on coming in contact with common salt
4. shrinking of grapes kept in thick sugar syrup
5. preserving of pickles in salt
6. spreading of smell of cake being baked in the kitchen
7. aquatic animals using oxygen dissolved in water during respiration

Explain why, osmosis can be considered to be a special kind of diffusion. Classify the following into

(i) osmosis, and (ii) diffusion  :

1. swelling up of a raisin on keeping in water
2. spreading of virus on sneezing
3. earthworm dying on coming in contact with common salt
4. shrinking of grapes kept in thick sugar syrup
5. preserving of pickles in salt
6. spreading of smell of cake being baked in the kitchen
7. aquatic animals using oxygen dissolved in water during respiration

An inflated balloon full of air goes down slowly (becomes smaller and smaller slowly) even though the knot at the mouth of the balloon is airtight. And after a week all the air has escaped from the balloon. Explain how the air particles got out of the balloon.

An inflated balloon full of air goes down slowly (becomes smaller and smaller slowly) even though the knot at the mouth of the balloon is airtight. And after a week all the air has escaped from the balloon. Explain how the air particles got out of the balloon.