Measuring Temperature
Physics: Cambridge International A Level, topic 1.2.2
The Key Properties of Thermometers
When using different thermometers, we should consider 3 things.
Linearity
- Linearity means that thermometers should have the same distance between all their intervals.
- This means that a change of 1 °C in temperature should always change the length of the column by the same amount.
- The size (diameter) of the thermometer should be constant all the way up the thermometer.
Sensitivity
- Sensitivity describes the level of precision in measurement.
- More sensitive thermometers can detect smaller changes in temperature.
- If a thermometer has a smaller diameter, then a 1 °C change in temperature will cause a larger increase in the length of the column.
- This increases the “sensitivity” of the thermometer.
Range
- If we know the volume of a liquid at two fixed points (for example 0 °C and 100 °C), then these two points constitute the range of a scale.
- Because of linearity, it is possible to calculate how much the volume changes for a 1 °C change in temperature between these points.
Test yourself on Measuring Temperature
Which key element describes the level of precision
Which key element enables the calculation of how much the volume changes for a certain change in temperature within a defined range?
Why does reducing the diameter of a thermometer increase its sensitivity?