Apparatus needed:
1. A large "filtering tube" (This is a large test tube which is open
at the top and narrows down into an opening at the bottom. If
not obtainable a long necked glass funnel is sufficient.)
2. A large glass fish tank or jar
3. A bag of charcoal pebbles, sand, and gravel obtainable at a retail
tropical fish store.
4. Micropore filter paper
5. Petri dishes
6. Chlorine (Obtainable at a retail outlet store that sells swimming
pool supplies)
7. A strainer (found in the kitchen) or screening