Matter in our surroundings – Class IX – In-text Solution (Part 1)

(Answers of In-text Question in NCERT Science Text Page 3)

1. Which of the following are matter ? - Chair, air, love, smell, hate, almonds, thought, cold, cold-drink, smell of perfume.

Ans : Chair, Air, Almonds, Cold-drink are matters as they occupy space & have mass.

2. Give reasons for the following observation: The smell of hot sizzling food reaches you several meters away, but to get the smell from cold food you have to go close.

Ans:

• Smell of anything  reaches to us because of diffusion of gases coming from it.
• The rate of diffusion increases with increase in temperature. This happens because of higher kinetic energy due to higher temperature. That is why smell of hot sizzling food reaches to us from several feet away.
• On the other hand, the kinetic energy of gases produced from cold food is low because of lower temperature. Due to this, we need to move closer to a cold food to take its smell.

3. A diver is able to cut through water in a swimming pool. Which property of mater does this observation show?

Ans:

• Water is also a matter.
• Particles of matter have space between them and in case of fluids, the space between the particles is large enough.
• Due to this it becomes easier for a diver to cut through water in a swimming pool.

4. What are the characteristics of the particles of matter?

Ans: Characteristics of the particles of matter:

• The particles of matter have space between them.
• The particles of matter are moving constantly.
• The particles of matter attract one another.