Reading scales

Most thermometers (temperature measurers) show the temperature marked on a scale. Each division on the scale represents the same number of degrees.

The first thing to do when you read a thermometer is to check the scale. The three thermometers shown above use different scales.

• Each division on A represents one degree. It is showing 6ºC.
• Each division on B represents two degrees. It is showing 8ºC.
• Each division on C represents five degrees. It is showing 50ºC.

If you look only at the red line, rather than reading the scale, it is easy to get a wrong answer to a question.

Example 1 8º on scale B looks lower than 6ºC on scale A.
Example 2 - 3ºC on scale A looks higher than 10ºC on scale C

Now look at these two thermometers:

Although the zero on each of these two thermometers is in the same position, and the divisions are the same distance apart, they show very different temperatures. The scale on D is marked in twos and E in fives, so although the red lines seem to be the same length the temperature shown by E (20ºC) is much higher than that shown by D (8ºC).