Evaluating means judging how good an experiment was. Ask: were the control variables really kept the same? Were there enough results, and were they repeated? Were there anomalous results, and can they be explained? Was the equipment precise enough?
Then suggest specific improvements, not just 'be more careful'. For example: 'Use a data logger instead of a stopwatch to remove reaction time,' or 'Take readings at 5 °C intervals between 30 °C and 40 °C, where the result changed most.' A strong evaluation links each weakness to how it affected the results and the conclusion.
Worked example
Pupils timed sugar dissolving with hand-held stopwatches and stirred by hand. Suggest one improvement.
- Stirring by hand may not have been the same each time.
- That is an uncontrolled variable.
Answer:Use a magnetic stirrer at a fixed speed so stirring is the same.
Key words
- evaluate
- judge strengths and weaknesses
- precision
- how close repeated measurements are
- improvement
- a specific change to make results better
- data logger
- equipment that records measurements automatically
New questions every time.
NGSS-referenced: MS-ETS1-3