3rd grade science fair projects are a lot of fun because at this age children are eager to explore the world around them and find out how things work. They are constantly wanting to know the answer to the question "What happens if I do this..." and therefore they will likely come up with many different experiments they'd like to try. It may be difficult to decide on just one! At this age they have a short attention span though, so the projects must be simple, fun and fairly short. There are many, many different project ideas for this age group such as; do all the children in their class have the same size hands and the same size feet as each other? They can research this by tracing the other children's hands and feet on a piece of paper and comparing them to each other. They could do a test to see if waterproof mascara is really waterproof. To do this you would need a couple brands of waterproof mascara, a piece of paper and some water. Simply put the mascara on...