Build a mini eco-system, and collect and interpret data on how well the plants grow under different conditions.
Do you know which birds are regular visitors where you live?
Investigate how avalanches occur and how they can be controlled
How does the time of dawn and dusk vary? What about the Moon, how does that change from night to night? Is the Sun always the same? Gather data to help you explore these questions.
Can you coach your rowing eight to win?
Could games evolve by natural selection? Take part in this web experiment to find out!
You may like to read the article on Morse code before attempting this question. Morse's letter analysis was done over 150 years ago, so might there be a better allocation of symbols today?