Summary: Carrying out an investigation

Identify the dependent, independent and controlled variables.
Suggest a hypothesis and explain the reasoning for this hypothesis.
Write a plan of your method to test your hypothesis.
Select the number of readings you will take and the range of readings.
Carry out a risk assessment.
Select suitable apparatus that will allow you to get appropriate and accurate results.
Draw a diagram of the apparatus used.
Draw a results table with labelled column headings and units.

Use good quality apparatus:

Repeat measurements to reduce random error.

Obtain and record enough results to test your hypothesis.
Carry out any necessary calculations.
Select the best type of graph or chart to display your results.
Look for any anomalous result in a set of experimental data and either repeat the measurement or disregard it.
Draw a conclusion - say what your results show, and how they relate to the hypothesis you made at the start of the investigation.
Discuss the reliability, repeatability and reproducibility of the data you collected:
- An accurate result is one judged to be close to the true value
- Reliability is affected by the number of results taken, including repeat readings and the range of results collected.
- Results are said to be repeatable if similar results are obtained when you repeat your measurements.
- The investigation is reproducible if you get someone else to follow your method and their results are like yours.

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