Q1.
Can you share a few other real-life situations where you have experienced the movement of gas particles?
Answer
Yes — the same thing happens many times every day. In each case, particles get from one place to another with nobody carrying them, because the air particles are moving constantly and keep knocking them along.
| Everyday situation | What is moving, and how you know |
|---|---|
| The smell of dal or tempering reaching the far room while food is cooked | Particles from the food spread through the air of the whole house |
| Camphor or an agarbatti lit in one corner of a temple | Its particles reach every worshipper, exactly as in Activity 7.9 |
| A mosquito repellent or phenyl used at one end of a room | The smell is soon present everywhere in the room |
| The smell of an LPG leak noticed from another room | The gas spreads on its own — which is why it is given a strong smell in the first place |
| Attar or perfume applied on the wrist, noticed by someone standing away | Vapour from the liquid spreads through the air to reach them |
| A cut onion in the kitchen making eyes water at the doorway | Particles from the onion travel across the room through the air |
| The smell of hot jalebis reaching you before you turn into the lane | Particles are carried outward from the shop in every direction |
Ever heard of … the chapter's own example of the particulate nature of matter at work: when oil-stained clothes are washed with soap, a large number of soap particles surround the oil particles on the fabric. One end of a soap particle attaches to the oil and the other mixes with water, so the oil is lifted off and washed away (Fig. 7.15).