It seems perfect for someone between 4th and 6th grade, since you can focus on how everyone has and uses fingerprints. You can use glue and tape to show how they can appear, the different types of prints, how they change etc. Its not too hard for one to understand.
That is a good idea, but how to present it is more of the issue. You will have to show the clear prints and point out the differences between them, so you would need a magnifying glass for people to look through, and observe the differences. Hope this helps, good luck to you.