PRINCIPLE OF THERMOMETRY

Temperature is the measure of the degree of ‘hotness’ or coldness’ of a body. The temperature of a body is a measure of the average kinetic energy of its’ particles. Because it is the average kinetic energy of a particle, it does not depend on the size of the object.

Internal energy is the total energy of all the particles;

Temperature is a measure of the average kinetic energy of the individual particles.
Temperature can be measured using a thermometer, which makes use of the physical properties of a thermometric substance which changes continuously with temperature .

Fixed Points
Before a thermometer can be used, it must be calibrated by placing it into ice and then boiling water, marking the scale each time. These two points are known as the fixed points:
0°C – the ice point – the freezing point of pure water at atmospheric temperature;
100°C – the steam point – the boiling point of pure water at atmospheric pressure.

Features of a thermometer
Responsiveness: measures how quickly the thermometer can register changes in the environment

Sensitivity: measures the amount of change in thermometric property per unit change in temperature.

Range: denotes the minimum and maximum temperatures that the thermometer can measure.

Linearity: scale is linear when the marks are evenly spaced.