Styrofoam is essentially plastic filled with many bubbles of air, which at sea level keeps the foam expanded, lightweight, and soft.

When a styrofoam cup travels with our probes down to the depths inhabited by abyssal creatures - 4000 metres this time - it returns to the surface shrunken and hard. At that depth, the pressure is 400 times atmospheric pressure at sea level. This enormous pressure squeezes the air out of the foam and shrinks the cup, helping to illustrate just how remarkable it is that animals can survive these intense environmental conditions.

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