Suppose you have an open-topped box that is 5cm x 5cm x 5cm (capacity: 125 cubic centimetres) Inside the box is a steel ball bearing that is 25 cubic centimetres in size. Next to the box is a two-litre pail filled with mercury. How many cubic centimetres of mercury would you have to pour into the box to submerge the ball bearing completely?
Answer
You couldn’t. Mercury is so dense steel that it floats in it.