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Ignition Learning — Activity Sheet

Designing a scientific investigation

Science · Year 11

Name: ______________________Date: ____________

Designing a rigorous scientific investigation starts with a clear, testable hypothesis — a specific, falsifiable prediction, not just a general question. A well-designed experiment identifies and controls variables carefully: the independent variable (what you deliberately change), the dependent variable (what you measure as a result), and control variables (everything else that must be kept constant to ensure a fair test). Repeating trials and considering sample size helps distinguish a genuine effect from random variation, while ethical considerations — informed consent for human participants, humane treatment of animal subjects, safety — must be addressed before an investigation begins, not as an afterthought.

Example

Testing whether a new fertiliser increases plant growth requires a controlled experiment: the independent variable is the fertiliser type (with and without it), the dependent variable is measured plant growth, and control variables (identical plant species, soil, water, sunlight and temperature for every group) must be kept the same so that fertiliser is the only factor that could explain any difference in growth between groups.

Key terms

Hypothesis:: A specific, testable and falsifiable prediction.
Independent / dependent variable:: The variable deliberately changed (independent) versus the variable measured as a result (dependent).

This topic is self-directed and doesn't have quiz questions.