Some claim that mountain climbers suffer from headaches due not only to a lack of oxygen in the brain, but also to the expansion of the brain in the cranium. Find the fractional change of the brain’s volume due to a reduction in pressure from 101 kPa at sea level to 31 kPa high in the Himalayas. The bulk modulus is 2.1 GPa. (Another reason the brain expands is the dilation of the blood vessels in the brain in order to deliver more oxygen.)