This is a tough assignment! I hope the prof gave plenty of guidance to help you understand experimental research.
How about if I wanted to test the question of whether my sunflowers will grow better if I talk to them every day. Have you ever heard of that idea? Many people swear that giving their plants attention makes them grow better.
In that example, the control group is the group of plants that you do not talk to.
That might not be the best example, because it has been done before. However, if you are in high school it is probably okay.
What about a variation of it? What about if you bought some mice from a pet store? The kind often used for snake food is very inexpensive, I assume. Buy 12 of them and divide them into an experimental group and a control group. Then, make a hypothesis like... it could be anything.... it could be that you hypothesize that the group you cuddle with and talk to every day will eat more food than the group you ignore.
So, you can have 6 mice in individual containers, and 6 mice altogether in a container that you often take into another room -- so you can play with them.
you should have NO problem filling 10 pages, because you are supposed to record every detail of your idea, the process, and the results.