The teens purchased two jars, placing meters in each to test the purity of the water. In one jar, the teens place shards of copper in the water - with the copper acting as the experimental contaminant. An electric fan spins the water while filtering floss - a type of fiber - collects contaminated particles. Once clean, the water is transferred by a straw into the second jar. The meters verify that the water is clean, and the teens said they trust their system so much, they drank the water.