Questions + answers = 9.4

Q1. which material, air or water, expanded more rapidly?
A1. The level in the tube indicates the temperature of the water; the higher the temperature, the higher the level in the tube.
Q2. Which material would make the more sensitive thermometre?
A1. When the water is heated, the water particles vibrate more quickly and the distance between them increases and the volume gets larger. The water in the tube is contrained in how much it can expad sideways, so the increase in volume leads to an increase in the water level. Conversely, when the water is cooled the water particles vibrate less rapidly and the spaces between the particles become smaller, which leads to a decrease.