You might be wondering how these huge cargo ships can float at all, with all those heavy cargo containers sitting on top of them. Let’s do a fun experiment to figure out why big, heavy things like cargo ships can float, but small things, like a penny you drop into the ocean, sink.

Why Cargo Ships Can Float Experiment - Student Instructions

Why Cargo Ships Can Float Experiment - Teacher Instructions

Sometimes, oil from cars, trucks and industry located along the Elizabeth River runs into the water. When this happens, the oil congregates on the surface of the water. Waves and currents in the water mixes some of the oil into the water, and harms plant and animal life that live on the surface such as sea birds and seaweed, or that need to come to the surface to breathe such as whales, seals and sea turtles. Over time, the water and oil mix somewhat, and some of the oil (which is heavier than the cooking oil we are using) will sink to the bottom of the river, harming the flounders, sea urchins, lobsters, crabs and other bottom dwellers. The Port Authority is
voluntarily cleaning up the river through their Mitigation Plan and ongoing clean-up activities.

Save the River - Student Experiment

Save the River - Teacher Instructions

When a Hopper, Cutterhead, or Mechanical Dredge machine heads out into Hampton Roads Harbor to dredge the bottom of the river, in order to make room for the cargo, cruise, and Navy ships that come through, the dredge loosens up the river bottom and at the same time sucks up the loosened material and shoots it out into the Dredged Material Management Area at Craney Island. This experiment demonstrates how a dredge works (on a very small scale).

Dredging in Hampton Roads - Student Experiment

Dredging in Hampton Roads - Teacher Instructions