Contents are appropriate for IGCSE Physics

1. TEMPERATURE

2.  Temperature is a measure of the average kinetic energy of
particles in a substance.
 Temperature is measured using a thermometer.
 The S.I. unit for temperature is degree-celsius (oC)or kelvin
(K)
 Every thermometer depends on some property of a
material that varies with temperature.
 Liquids that expand uniformly (i.e. linearly) with
temperature are used in thermometers.
 Thermometers that use liquids are called liquid-in-glass
thermometers.
 Digital thermometers use materials whose resistance
changes with temperature.

4. Fixing a temperature scale
 To create a temperature scale, two standard
temperatures must be chosen against which others can
be judged e.g 0oC and 100oC
 0oC is the lower fixed point
 100oC is the upper fixed point
 Once the 0oC and 100oC have been fixed, the rest of the
scale is made by dividing the distance between them
into 100 equal divisions or degrees.

5. Properties of a liquid-in-glass
thermometer
1. Sensitivity: thermometers whose liquids expand
more due to a slight change in temperature are more
sensitive. The narrower the tube, the higher the
sensitivity of the thermometer.
2. Range: mercury freezes at -39oC and alcohol at
-115oC. However, alcohol boils at 78oC while mercury
at 500oC. Mercury has a larger range than alcohol.
3. Responsiveness: a thermometer with a larger bulb
takes longer to respond to temperature change.
4. Linearity: a thermometer should respond to
temperature change uniformly.