3. How to design an experiment

Question 1

Aim

Answer 1

• A single statement that describes the purpose or reason why you’re conducting an experiment.
• This usually involves proposing a possible connection between two variables: the independent variable (what you’re going to change) and the dependent variable (what you’re going to measure).

Question 2

Experimental hypothesis

Answer 2

A prediction of what change(s) will take place in the dependent variable when the independent variable is manipulated.

Question 3

Dependent variable*

Answer 3

The effect you are going to measure, to see if changing the independent variable has an impact.

Question 4

Independent variable*

Answer 4

What you’re going to change in the experiment, to see if the changes have an effect on the dependent variable.

Question 5

Materials

Answer 5

All the things you will need to prepare in order to do the experiment.

Question 6

Participants

Answer 6

Who you’ll do the experiment on.

Question 7

Standardised procedure

Answer 7

A step-by-step description of what will happen when you are conducting the experiment.

Question 8

Controls

Answer 8

The things you will be careful to keep the same for every participant, in order not to ‘pollute’ your experiment with variables that you’re not trying to test.

Question 9

Data

Answer 9

The information you’ll get back by doing your experiment that will allow you to test your experimental hypothesis.