Each group needs:

• test water with suspended solids, ~1 liter in a container with a lid
• 7 clear plastic cups
• aluminum sulfate solution, ~3 ml (prepared by teacher)
• polymer flocculant solution, ~3 ml (prepared by teacher)
• 4 plastic spoons or craft sticks, for stirring
• marker, able to mark on the plastic cups
• lemon juice, ~2 ml
• volumetric measuring tool(s), for measuring 1 ml of additives (such as pipettes; clean between use)
• lab journals, or paper and pencil, to record lab notes and observations
• (optional) pH paper

For materials preparation (done by students or prepared by teacher in advance):

• Containers in which to collect "dirty water" from a nearby river or pond; enough to collect ~ 1 liter per group; make sure to scoop up some riverbed silt and dirt during collection
• 2 containers with lids for the aluminum sulfate solution and polymer flocculant solution
• aluminum sulfate (aka alum; purpose: flocculant), a small amount, about the size of a quarter; available at grocery stores in the spice aisle, for example, McCormick's 1.9 oz [53 g] jar for $3.49
• Super Blue concentrated pool water clarifier (purpose: polymer flocculant), a small amount, ~1 ml per 50 ml of water; available at pool supply stores or on the Internet for $13 per quart
• tap water, ~10 ml per student group (purpose: flocculant suspension/dilution)
• tape and marker, to label the containers