'allo! I know it seems awkward that I posted an earlier thread about this topic, but roll with it. I would like to share what I (our group) am going to make for our science fair project. It is an alternator that uses collected rainwater to rotate the rotor. It will work like this: At the top part, there is a collection vat. It's about 1m x 1m x 1m in size. Below it is a tube leading down to the water wheel of the generator. There will be a valve along the way, so you can set when you want to activate. The water makes the wheel spin, turning the rotor of the alternator. Right below the generator is another pipe, but wider in diameter. The 2nd pipe will lead to a basin so that the water can be reused, just in case the rain stopped. How are we going to present how it works at the fair if there's no rain, you ask? Well, we plan to use laundry water to make the water wheel move. Thoughts?