Describe an experiment to demonstrate that a substance absorbs heat during melting without change in its temperature.

The following experiment demonstrates that a substance absorbs heat during melting without change in its temperature —

1. Take a test tube with some wax in it.
2. Clamp the test tube in a vertical stand and place the test tube in a beaker of water.
3. Place the beaker on a wire gauze which is kept on a tripod stand.
4. Clamp a thermometer in the same vertical stand and insert the thermometer in the test tube such that the bulb of the thermometer is inside the wax as shown in the figure above.
5. Heat the beaker over the flame of a burner.
6. Record the temperature of the wax from the thermometer after every minute.

Observations:

Conclusion: From the above observations, we can conclude that wax melts at 55°C during which heat is supplied but the temperature does not rise. Hence, wax absorbs heat during melting without change in its temperature.