Do a science fair project

Your science fair project may do one of three things:
1-Test an idea (or hypothesis.)
2-Answer a question.
3- Show how nature works.

Pick a topic. Try to find out what people already know about it.
Do one of these: State a hypothesis related to the topic. That is, make a cause-and-effect-statement that you can test using the scientific method.
Explain something. Make a plan to observe something.