If a student measures ice melting time at different temperatures what is temperature?

Correct answer: Independent variable

The direct answer is B: independent variable. The independent variable is the factor that the investigator deliberately changes to study its effect. The dependent variable is what is measured in response. In this investigation, the student uses different temperatures and measures the time taken by ice to melt. Step by step: identify what is changed—temperature; identify what is measured—melting time; the changed factor is therefore the independent variable. Option A is wrong because melting time is the dependent variable: it changes in response to temperature and is measured. Option B is correct because temperature is deliberately varied by the student. Option C is wrong because a controlled variable is kept the same, such as the ice mass, container, or room conditions where possible. Option D is wrong because a constant is a quantity intentionally held unchanged, not the factor varied across trials. The experiment is strongest when only temperature changes and other relevant conditions remain the same. Memory cue: independent means “I change it”; dependent means “data depend on it.”