Eric Koser and his 9th grade physical science students at Mankato West High School in Mankato, Minnesota, had spent a lot of lab time doing experiments studying mass, volume, and density with overflow cans. When the discussion of the density of a person came up, Eric took on the challenge to measure it.

Fortunately, one of Eric’s colleagues is married to a welder, and she had her husband build a human-sized overflow can out of a 55 gallon drum. Eric placed four Vernier Force Plates adjacent to each other. He then placed a board on the sensors on which the drum sat. This allowed his class to monitor the total weight of the drum, water, and Eric, as he climbed in.

The calculation of the total weight from the four Force Plates was plotted against time during the experiment. The class found it interesting that the initial weight of the water and drum was comparable to the final weight of the water, drum, and person together. This helped them to realize how close the density of a person is to that of fresh water.

To complete their measurements, a fifth Force Plate was used with events with entry mode to determine the mass of each bucket of water they collected from the drum.

This was surely an experiment that Eric’s students will not soon forget.