9. Complete Activity 3.9 (Page 31). Light a candle. Keep one hand above the flame and one hand on the side of the flame (Fig. 3.10). Do your hands feel equally hot? If not which hand feels hotter? And why?
Answer: The above activity can be carried out as follows:
Aim: To find how heat transfer happens in air.
Materials Required: Left and right hand, candle.
Procedure:
(i) Light the candle.
(ii) Put your left hand on the side of the flame and the right hand above the flame as shown below:
Observation:
You will find that the right hand above the flame feels hot and the left hand beside the flame looks comparatively cold.
Conclusion:
The air near the heat source gets hot and rises, which makes right hand above the flame hot. The cooler air from the sides comes in to take its place, therefore the hand on the side feels cooler. Therefore, air gets heated by this process is known as convection.
Related Links:
Solution to Extended Learning Problem 1
Solution to Extended Learning Problem 2
Solution to Extended Learning Problem 3
Solution to Extended Learning Problem 4
Solution to Extended Learning Problem 5
Solution to Activity 3.1
Solution to Activity 3.2
Solution to Activity 3.3
Solution to Activity 3.4
Solution to Activity 3.5
Solution to Activity 3.6
Solution to Activity 3.7
Solution to Activity 3.8
Solution to Activity 3.10
Solution to Activity 3.11
Solutions to Chapter 3 Heat
