Question

List any four applications of thermal expansion in day-to-day life.

Answer 1

Applications of thermal expansion:

1. Thermometer-Devices used for temperature measurement are different thermometers, thermocouples, or digital thermometers. Thermometers contain mercury or any other fluid. Temperature is directly proportional to an expansion of mercury. As soon as the temperature increases it causes fluid to expand. Hence, the temperature can be measured by measuring the volume of fluid.
2. Gaps which are of the order of a few millimeters, in railway tracks are provided to allow room for the rails to expand the rise in temperature due to the atmospheric temperature as well as the friction caused by the running of the train. All materials expand when heated and contract when cooled.
3. In a thermocouple as the temperature of the hot junction is increased with the cold junction at a fixed temperature, the thermal emf increases until a maximum temperature called the neutral temperature. A further increase in temperature will make the emf fall until the temperature becomes zero known as the temperature of inversion.
4. Iron rims are heated before they are fixed on the wooden wheel, to ensure a tight fit, the tyre is made slightly smaller in diameter than the wheel. As the tyre is first heated due to which it expands it is then fitted on the wheel. When the tyre cools, it contracts and makes a tight fit on the wheel.