When you design your own experiment be imaginative. Equipment need not be expensive and you can often use items from your own home.

Small empty glass juice bottles make excellent breeding containers for small insects or for mixing chemicals.

Make sure you prepare a full list of equipment used. Use drawings, diagrams, sketches and photographs to record what you are doing. There should be enough information to enable someone else to repeat your experiment (and get the same result).

When you present your Science Fair Project you may only need to summarise the method. However, in your laboratory report it will need to be reported in full. Variables

Did you see how the idea of variables snuck in from nowhere?

Actually, we have already talked about one variable. In my maggot example it is temperature. It is going to be the one part of your experiment that is going to change. Here are a few examples.

·Which household cleaner kills most bacteria? Variable = household cleaners.

·How does bridge design affect weight carrying capacity? Variable = design.

·Which upgrade has most effect on a computers speed? Several variables are possible here = hard drive, processor, memory.

·Does temperature alter a magnets strength? Variable = temoerature.

Limiting the number of variables and being able to measure and control these variables is essential to your projects success. It enables you to (yes you have seen this list before) -

• Keep it simple.
• Focus on one question.
• Make a prediction.

Control as many variables as possible.

One other very important thing about variables. You must be able to identify and control as many variables as possible. Your goal is to isolate the one factor you are investigating. I’ll illustrate this with a couple of examples.

The development of maggots might be altered by food source, species of fly, size of container, population the maggots were taken from or light/dark.

The strength of a bridge might be influenced by construction materials or size.

Computer speed might be influenced by temperature or operating system.

Identifying variables is the first step in controlling them.

Control Variables