The efficiency of different solar cell designs: This project would compare the efficiency of different solar cell designs by measuring how much electricity they can generate from sunlight.

The effectiveness of different water filtration systems: This project would test the effectiveness of different water filtration systems.

The aerodynamics of different paper airplane designs: This project would compare the aerodynamics of different paper.

The strength of different types of knots: This project would test the strength of different types of knots, such as the square knot.

The efficiency of different heat transfer methods: This project would compare the efficiency of different heat transfer methods