Would you like to do a simple science project with your 5th or 6th graders? This was designed as a prelude to a much more challenging middle school science fair project.
In this project, students choose a few household products to compare e.g. which laundry soap gets clothes the cleanest, which ketchup is the thickest, and etc.
This document is 20 pages and is saved as a Word document so you can customize it as you would like. It is very thorough and both student- and teacher friendly. It even includes the grading rubrics.
I currently teach middle school science, but have taught all science to grades 3-8, so please let me know if there is something specific for which you are looking.