There are so many different angles you can take with this science project. The project itself is constructed out of recycled plastic. It teaches water filtration, erosion, and the need for leave no trace when hiking. You will need scissors, three 2 liter soda bottles, 3 small water bottles, grass seeds (we used rye grass), soil, and leaves, twigs, pebbles (materials to replicate the forest floor). First cut horizontal squares in the soda bottles. Next, cut the water bottles in half, poke holes on both side and tie a twine handle so they can catch the water. In the first bottle put plain soil. In the second, first put soil then all the materials you can find to replicate a forest floor. In the last bottle put soil and grass seeds. Each day water the three bottles and observe the water that pours into the small water. The plain soil water will be dirty while the other two will be significantly cleaner. The experiment demonstrates how forest floor debris and grass serve as a water filter. In return the run off that deposits into lakes and streams is cleaner. It also demonstrates the importance of not wandering off trails when hiking. When you disturb the natural vegetation and make new worn paths you are creating more parts of the forest that is just soil.