As part of your course you’ll have to undertake practical experiments. Knowing how to work accurately and safely will help you to get the best results from your experiments so we have prepared this guide to investigative and practical skills.

Investigating Biological Problems

When you carry out a scientific experiment the object is always to try and find out a result which will help you to understand how something works. In order to design your own experiment you need to know, or at least be able to make a good guess, about cause and effect relationships between what it is you’re going to change and what is it you’re measuring.

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Variables

This is why, before carrying out an experiment, scientists come up with a prediction, called a hypothesis, on what the effect will be of changing a particular variable.

The variable that you want to change is known as the independent variable. The variable that’s affected by the changed variable is known as the dependent variable. Your hypothesis would therefore be something on the lines of:

changing independent variable X will have some kind of effect on dependent variable Y

In order to see what the effect of changing an independent variable is you need to isolate its effects. This is best achieved by only changing one variable at a time. Control variables are the variables that are kept constant during the experiment.