Polystyrene cup deformed by high pressure under the sea. The cup on the right has a capacity of around 400 millilitres. The cup on the left was identical to this before being taken down to a depth of around 3000 metres by the research submersible Alvin. The enormous pressure at that depth, equivalent to around 300 atmospheres, has compressed the cup to this form. The lettering ALVIN, written on the cup before its descent, has also been compressed. Alvin is a deep sea research vessel operated by the Woods Hole Oceanographic Institution, USA.