Ruler, Thermometer and Stopwatch


A metre rule has sensitivity or accuracy accuracy of 1mm.
Precaution to be taken when using ruler

  1. Make sure that the object is in contact with the ruler.
  2. Avoid parallax error.
  3. Avoid zero error and end error.


There are 2 types of mercury thermometer

  1. Thermometers of range -10oC – 110oC with accuracy 1oC.
  2. Thermometers of range 0oC – 360oC with accuracy 2oC.

Precaution to be taken when using a thermometer

  1. Make sure that the temperature measured does not exceed the measuring range.
  2. When measuring the temperature of a liquid
    1. immerse the bulb fully in the liquid
    2. stir the liquid so that the temperature in the liquid is uniform
    3. do not stir the liquid vigorously to avoid breaking the thermometer


There are 2 types of stopwatches

  1. analogue stopwatches of sensitivity 0.1s or 0.2s
  2. digital stopwatches of sensitivity 0.01s.

The sensitivity of a stopwatch depends on the reaction time of the user.

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