A science fair question is the very beginning of a science fair experiment. A science fair project question might start with something like: "Why does.." or "How will..." or "Where does..." and so forth.
In our tomato plant example our question might be: "Is tomato plant growth speed affected by the structure of it's growth medium?" This question is asking whether tomato plants will grow better or worse in soil or water if everything else is equal.
An experiment is just a trial where you are trying to figure out whether something is true or not. So, ultimately, you are going to try and answer your science fair question by doing an experiment.
You have to be careful with your science fair question – if what your question is asking is not measurable then it will not make a good science fair experiment.
Avoid questionnaire type questions that require people to give opinions, their impressions, or their memories – this is not science because it is not objectively measurable.
Avoid dangerous science fair experiments! There is no need – there are plenty of cool science fair experiments out there that do not require caustic chemicals or other dangerous materials.
Avoid immeasurable science fair experiments – science relies on measurements, if you can't measure what you're doing then you can’t do science.
And lastly – be creative! When you look at what people do at science fairs, you will see a lot of the same kind of simple (and boring) science experiments year after year. Spend a little time now and come up with a science fair experiment that you can be proud of – it will pay off in a big way.
So what do you want to come up with when forming your science fair question? Look at the research you did on your topic of interest and your list of ideas you came up with during your brainstorming session. Think about a specific question you have about your topic.
What if your topic was plant growth in (nutrient filled) water instead of soil (hydroponics)? An example of a science fair question for you might be: “What is the growth speed difference between tomato plants grown hydroponically versus those grown in potting soil?”
If you look at the hydroponically grown tomato example above, you’ll see that we were very specific in what we were asking: “What is the growth speed difference between tomato plants grown hydroponically and those grown in soil?”
When you have a question in mind, you will want to take note of three things:
An Independent Variable is what you (the scientist) are changing or enacting in order to do your science fair experiment – there is only oneIndependent Variable in any valid experiment and in our tomato experiment it would be the difference in growing mediums for our tomato plants (one is a nutrient solution and the other is soil.)
The Dependent Variable is what changes as a result of the Independent Variable – so in our example it would the growth difference in the tomato plants.
There can be more than one Dependent Variable. In our example the growth difference in the tomato plants might be measured in the height of the plant and in the size of the tomatoes. Each of these would be a separate Dependent Variable.
Lastly Controlled Variables are the things that you the scientist would want to keep constant (unchanging) throughout your science fair experiment.
In our science fair experiment an example of a Controlled Variable would be the amount of light each plant (the ones in nutrient solution and the ones in soil) would receive – we want that amount to be the same, otherwise it could affect the growth of the plants differently and therefore cause the experiment to fail because we would not know if difference in plant growth were due to the different growth mediums or different exposures to light.
When doing your science fair experiment it will be very important for you to identify any Controlled Variables that might affect the outcome of your experiment.
Got your science fair question? Great, let’s go on.