Once you have an area of interest in mind, you’ll want to narrow it down to a question that you’d like to learn more about. Your project will be based on designing an experiment to try and do just that, learn more about the answer to your question.
For example, you may have a general interest in Life Science, and then narrow that down to the general topic of plants. Maybe you’re interested in understanding more about what plants need to grow. Here are some example questions about how plants grow:
Question 1: Can plants grow without light?
Question 2: Which plant food works best?
Question 3: Is it possible to give plants too much water?
An important feature of a good scientific question is that it tests to see the effect of one thing. In each of our example questions one thing is changed and we measure how it affects the plants. In question 1 we change the light. In question 2 we change the kind of food. In question 3 we change the amount of water. We call the thing that gets changed the experimental variable, or the independent variable. Plan so that your experiment has only one experimental variable - everything else about your experiment should stay the same.
Finally you’ll need a hypothesis. A hypothesis is a prediction that you make about what you think will happen in your experiment. People sometimes call it an “educated guess” because you don’t know for sure what will happen, but you’re saying what you think will happen, based on what you already know. Here are some example hypotheses for the example questions:
Hypothesis 1: If I put some plants in the dark they will not grow as well as plants that I put in the light.
Hypothesis 2: I think that plants that are fed with Miracle-Grow will grow taller than plants that are fed Flora Bloom.
Hypothesis 3: I hypothesize that if I over-water cactus plants they will be harmed as compared to cactus plants watered as directed.