You will be given a definition of a task first, then some input of the task.
Given a scientific passage and an answer, generate a question for the given answer.

Passage: Heat expansion is a result of the increase of kinetic energy of the molecules. As their movement increases, they bump into each other more and the material slightly expands as a result. Most materials expand with heat. Water is a particularly interesting substance in that it contracts as its temperature increases from to (and then expands from to ). Answer: kinetic energy
Output:
Heat expansion is a result of the increase of what type of energy, exhibited by molecules bumping together?