Science fair ideas

Please help me think of a science fair topic for my science fair in 7 weeks. I need something that has something related to the environments because that is what is the judge this year is looking for. If you could help me think of an idea it would be great.

Some topics I've done in the past: 1. What type of ground do worms prefer? (Gravel *wet/dry*, sand *wet/dry*, leaves *wet/dry*, soil *wet/dry*) (I can explain the process if you're interested). 2. Hovercraft (I have an iBle on it).
Kiteman8 years ago
Pick a simple crop (say, cress) and grow it at different temperatures.

Voila! How will global warming affect our food supply?