Chemical or Physical Change - let the students decide. Students may be given the full step by step procedure, or perhaps allow for more of a disovery / inquiry based approach, prompting with "what should we do next to determine if this is a chemical or physical change?"
This comprehensive website is full of ideas, tips and tricks for a successful science fair project. There is even a "Topic Selection Wizard" that gives students a brief survey, then recommends projects that are best for him or her according to grade level and time available!
The water cycle is much more than memorizing words like EVAPORATION and PRECIPITATION. The Activity to the right is a great classroom exercise that can strengthen your understanding of the water cycle. Check out the 3 interactive Shockwave animations below. Each animation builds on the previous one so start at the beginning and work your way up.
This resource is part of the Biology Links for One Laptop Per Child course which contains units on Exploring Life; The Cell; Genetics; Mechanisms of Evolution; The Evolutionary History of Biological Diversity; Plant Form and Function; Animal Form and Function; Ecology; and Astrobiology.