Science inquiry skills

Biological inquiry starts with a question that evidence can actually answer. An investigable question names the organism or system, the factor that will be changed and the response that will be measured, for example: How does the temperature of a yeast and glucose suspension affect the volume of carbon dioxide released in ten minutes? Broad questions such as Why do cells respire? cannot be tested directly.

They must be narrowed until there is one independent variable and one measurable dependent variable. Background research is part of this step: it tells you what is already known, which range of values is sensible and which measuring techniques are realistic in a school laboratory.

A hypothesis is a proposed, testable explanation of a relationship between variables. In TASC Biology it should be justified, precise and testable. Justified means it is linked to a biological reason, such as the effect of temperature on the kinetic energy of molecules or on the shape of an active site. Precise means it names both variables and the direction of the expected change. Testable means data could be collected that would support it or fail to support it.

A reliable structure is: If [the independent variable changes in a stated way], then [the dependent variable changes in a stated way], because [biological reason]. A hypothesis is never proven; results either support it or do not.

A prediction is the specific result you expect from your own set-up if the hypothesis is correct, such as the number of millilitres of gas collected at each temperature. Thinking through the possible outcomes before collecting data helps you decide in advance what would count as evidence for or against the hypothesis, so you do not reinterpret results to fit afterwards.