• Can be measured in millimetres (mm), centimetres (cm) or kilometres (km).
• Can be measured using Vernier calipers where it can measure the thickness of outer diameter, inner diameter and depth of an object.
• Vernier calipers is more accurate compared to a ruler

• Systematic error - caused by using measuring instruments that are no accurate
• Example: Zero error can be determined when the jaws of the vernier calipers are closed.

To obtain the actual reading, zero error has to be taken into consideration.

Actual reading = Reading of vernier calipers - zero error

• Mass can be measured using digital electronic balance accurately and precisely

• Time can be measured using stopwatch accurately to 0.01 seecond

• A digital thermometer can give accurate reading of temperature up to \(0.1^\circ\text{C}\)

• Ammeter is used to measure electric current in a circuit
• A digital ammeter gives more accurate and precise readings with accuracy up to 0.01A.

• A measuring cylinder can measure the volume of water
• Parallex error occurs when the reader's eyes are not peperndicular to the reading scale

• Zero error
• Inaccurate measuring instrument

• Conduct experiments with caution
• Repeat experiment using different measuring instruments