Question

Give reasons why – 

1. a steam burn is more damaging than a burn caused from boiling water at the same temperature. 

2. an igloo is built as a winter shelter 

3. gaps are left between railway tracks 

4. chimneys are located high up in kitchens and factories 

5. we wear woollen clothes in winter.

Answer 1

1. A steam bum is more damaging as when steam hits our skin it condenses to water and attains the temperature of our skin. There will be an energy release due to latent heat and fall in temperature. Whereas when boiling water fall on our skin, there is no transition in energy, only fall in temperature and heat transferred to the skin will be due to cooling.

2. igloo is built as a winter shelter due to snow’s insulating property. The inside of an igloo acts as an insulator and keeps it relatively warm. 

3. During summer, heat causes expansion in tracks that are made of metal. If gaps a re not left between tracks, the track may bend due to expansion and accidents can occur. 

4. As hot gases and smoke are lighter, they rise up. Therefore chimneys are placed high up in kitchens and factories, so that the hot air can rise up and go out into the atmosphere. 

5. We wear woollen clothes in winter, as wool acts as an insulator. The air trapped between the woollen sweater and our clothes acts as an insulator and does not allow air from outside to enter, thereby keeping us warm.