Science · Grades 9–12
Investigations, controls and cautious conclusions · Revision card
Identify the factor changed, the outcome measured and important controlled factors.
Understand the idea
Separate variables
Identify the factor changed, the outcome measured and important controlled factors.
Evaluate uncertainty
Measurement limits, biological variation and sampling can affect results.
Match claim to design
An experiment supports only conclusions justified by its design and data.
Worked examples
In a test of light level and growth, which is the dependent variable if height is recorded?
The dependent variable is the measured outcome.
plant height
Why is random assignment to conditions useful when it is feasible?
It does not guarantee identical groups or remove every source of bias.
It helps distribute pre-existing differences among groups, reducing systematic confounding.
Explain without looking
- Which practice strengthens a report?
Preview material · independent educational review required. Grade bands are approximate, not official curriculum alignment.