Water Rocket: The combination of water, compressed air, and a plastic soda bottle serves as a great source of propulsion for a water rocket. Alternate way (without tape) to fix up those water bottle rockets. by elsa
All Of Earth's Water In A Single Sphere This picture shows the size of a sphere that would contain all of Earth's water in comparison to the size of the Earth. The diameter would be roughly the distance from Salt Lake City, Utah to Topeka, Kansas.
Bottle Bank via Martha Stewart: transform a used plastic bottle into a cute piggy bank. Could use same idea to made little containers for kids to store their collections too (use bottle with wider opening and don't make slot)