Thermometer definition: 1 Mark
Working: 2 Marks
A thermometer is an instrument which is used to measure the hotness of a substance.
The bulb comes in contact with an object and receives heat. This heat is conducted to the liquid inside the thermometer. This liquid which is usually Mercury expands uniformly depending on the amount of heat absorbed by the bulb. Depending on how much the liquid has expanded, the thermometer gives the respective reading.