10. Complete Activity 3.10 (Page No: 32). Take two identical tin cans. Paint the outer surface of one black and of the other white. Pour equal amounts of water in each and leave them in the mid-day sun for about an hour. Measure the temperature of the water in both the cans. Do you find any difference in the temperatures? In which can is the water warmer?
Answer: Find the details of the experiment below:
Aim: To find in which container – black or white – the water is warmer and provide an explanation.
Materials Required: Two identical containers – the outer surface of one is painted black and the outer surface of another is painted white, water, thermometer, hands.
Procedure:
(i) The container with the outer surface painted black and the container with the outer surface painted white are filled with equal amounts of water.
(ii) The two containers are left in the mid-day for about an hour.
(iii) After one hour, measure the temperature of the water in both the cans with the thermometer and also by touching with your hands.
Observation:
You will find that the temperature of water in the black container will be higher. Also, when you touch the water in the black container, it will feel warmer.
Conclusion:
The black surface absorbs more heat from the sun, which travels to the water inside by conduction and heats it up. The white surface on the other hand reflects most of the heat that falls on it and does not absorb much. Thus, the water in the black container is warmer than that in the cold container.
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 3.9
Solution to Activity 3.11
Solutions to Chapter 3 Heat
