Complete Activity 4.4 (Page 43). (Caution: Be careful while handling burning candle). Make two paper cups by folding a sheet of paper. Pour about 50 mL of water in one of the cups. Heat both the cups separately with a candle (Fig. 4.5). What do you observe?
Answer: The above activity can be carried out as follows:
Aim: To observe what happens when you heat both paper cups with the candle and conclude based on that.
Materials Required: Candle, two paper cups, 50 mL water.
Procedure:
(i) Make two conical paper cups by folding the sheet of paper.
(ii) Pour about 50 mL of water in one of the cups.
(iii) Carefully heat both the cups separately with a candle and note the observations.
Observations:
We observe that:
- The empty paper cup catches fire.
- The paper cup with water does not catch fire. The water in this cup becomes hot.
Conclusions:
We conclude that:
- The heat supplied to the cup filled with water gets transferred to water by conduction. So in the presence of water the ignition temperature of the paper is not reached and hence it does not catch fire.
- The empty paper cup does not contain water and thus its ignition temperature is reached. Hence, it catches fire.
“(Caution: Be careful while handling burning candle). Make two paper cups by folding a sheet of paper. Pour about 50 mL of water in one of the cups. Heat both the cups separately with a candle (Fig. 4.5). What do you observe?” – Solved.
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 4.1
Solution to Activity 4.2
Solution to Activity 4.3
Solution to Activity 4.5
