English Medium Class 9 - CBSE Question Bank Solutions for Science

Which of the following diffuses fastest and which the slowest?
Solid, Liquid, Gas Give reasons for your answer.

How does fumigation differ from spraying ?

Write down three unique characteristics of storage structure.

Name the three states of matter. Give one example of each.

State two characteristic properties of a gas.

Describe how drying of food grains is done.

As an incharge of a grain store, how will you find out the presence of pests ?

Describe the various methods of controlling pests attacking stored grains.

Why do gases have neither a fixed shape nor a fixed volume?

Give two reasons to justify that Water is a liquid at room temperature.

When an incense stick (agarbatti) is lighted in one corner of a room, its fragrance quickly spreads in the entire room. Name the process involved in this.

A girl is cooking some food in the kitchen. The smell of food being cooked soon reaches her brother's room. Explain how the smell could have reached her brother's room.

What does the diffusion of gases tell us about their particles?

Give one example of diffusion of gases in a liquid.

Give reason for the following observation :

The smell of hot sizzling food reaches us even from a considerable distance but to get the smell from cold food, we have to go close to it.

Explain how, the smell of food being cooked in the kitchen reaches us even from a considerable distance.

Explain why, when a bottle of perfume is opened in a room, we can smell it even from a considerable distance.

Explain why, diffusion occurs more quickly in a gas than in a liquid.

Why do gases diffuse very fast?

Name two gases of air which dissolve in water by diffusion. What is the importance of this process in nature?