Conducting Investigations Level 2

Measure reliably

How do we ensure reliable measurements?

Errors are a natural part of measurement. Errors can be minimised by taking a number of measurements and calculating the mean (average).


Some activities result in the ‘destruction’ of the items being measured. If you are germinating seeds, at the end of the activity you no longer have seeds, but seedlings instead. You therefore cannot repeat the activity with the original seeds, so instead you replicate it by doing the activity with a large number of seeds in the first instance. In addition some activities use things that have a great deal of natural variation. Living things, as the subject of investigations often pose this problem. If you want to test the effectiveness of a sport drink, you need to replicate the activity over a large number of students. Results for the seedlings or students are averaged.


If you are measuring how high a ball rebounds, you can safely repeat the activity and take a number of measurements. Repetition of measurements can reduce error and increase accuracy.


An activity is considered reliable if it can be repeated or replicated and still achieves the same result.

For scientific research to be accepted, it must be presented in such a way that peers can replicate it and establish that the results are the same.