| Date | May 2015 | Marks available | 1 | Reference code | 15M.1.HL.TZ1.6 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 1 |
| Command term | Deduce | Question number | 6 | Adapted from | N/A |
Question
What property of water makes it suitable as a coolant?
A. It takes a lot of energy to increase the temperature of water.
B. It takes a lot of energy for water to evaporate.
C. Water molecules are cohesive and stick to the skin.
D. Water is a good solvent so it can transport heat from the body.
Markscheme
B
Examiners report
This question also elicited some criticisms from teachers, who felt that there were two correct answers. Water cools living organisms when it evaporates so B was the correct answer. Water does conduct heat away from active muscles when blood flows through them and the heat is lost to the environment when the blood passes to the skin, but this can be regarded as a means of redistributing heat in organisms rather than actual cooling.
