To demonstrate that our oceans, despite their size, are a closed system.
One quart or larger plain glass bottle with a tight lid
Green and blue vegetable dye
Paint thinner (turpentine)
Duct or other waterproof tape
1. Fill the bottle half-way with water.
2. Add green and blue dye to make it look like the ocean.
3. Fill the bottle all the way to the top with paint thinner.
4. Put the cap on tightly and wrap it with duct tape to keep it from leaking.
5. Put the bottle on its side. Be careful it doesn't roll off the table!
If something happens inside the bottle, it effects all the water. Discuss how the motion of waves could carry and disperse pollution. How many students have seen trash washed up on shore at the beach?