Using yeast to represent oxygen consuming microorganisms or animals, the effect of temperature on biological oxygen demand and dissolved oxygen in water is explored, relating this to the metabolism of an organism. Further activities investigate chemical pollution by direct poisons (lead irons) and indirect (phosphate ions) that disrupt what lives in water by favoring the growth of one type of organism.

The kit provides enough material for 12 groups of students and takes two 45 minute class periods, followed by two to three days of observing results.