A blacksmith wishes to cool his hot piece of steel as rapidly as possible. He has a bucket of ice-water and a bucket of oil (at room temperature). Which bucket should he dump his steel into?
Interesting debate and question. My skills are such I can play
judge here. To wit: the people who disagree with the solution are
correct. Here is why. The cooling mostely occurs due to
convection. Without a strong gravitational field, little cooling
occurs. The flow rate is probably proportional to the differences
in density between hot and cold regions. The oil case, once below
the oil's boiling point, results in delta-rho's of ~2. The water
case results in delta-rho's of ~100. So you get faster convection
with water. In other words, the steam speed is much faster than
the hot oil speed. The situation reverses itself in strange
cases, such as if you moved the steel very rapidly through the oil.
Indeed wrong: ice is faster, here is why
