Temperature scales (14.2)

What are the properties of a substance be used to measure temperature?

If a property of a substance varies with temperature it can be used to measure temperature

1) Volume of a gas/liquid is calibrated to temperature

2) Density of a liquid is calibrated to temperature

3) Resistance of varies with temperature

4) e.m.f of a thermocouple - 2 wires create a voltage at one end when the other has an increase in temperature

Why are the accuracy of thermometers limited?

Thermometers are calibrated at certain fixed temperatures and we assume a linear variation of the property, which is used to measure the temperature, between these points.

What is thermodynamic temperature scale?

Thermodynamic temperature scale - a temperature scale based only on the laws of thermodynamics

It doesn’t depend on the physical properties of any particular substance (e.g. Celsius depends on properties of water)

What is the lowest temperature?

0 K on the thermodynamic temperature scale is the lowest temperature possible and particles at this temperature have minimum potential energy

0 K = -273.15 °C

How do you convert between Celsius and Kelvin?

T(K) = θ(°C) + 273.15

θ(°C) = T(K) - 273.15