You partially fill an Erlenmeyer flask (wider at the bottom than the top) with cold water. You measure the pressure at the bottom with a sensitive barometer. You heat the water until it is nearly boiling and measure the pressure at the bottom again. What happens to the reading of the barometer?
A) It increases a lot.
B) It increases a bit.
C) It remains the same.
D) It decreases a bit.
E) It decreases a lot.
Credit to Herbert Grotewohl for inspiring this question.