(a)[2]
He measures the length of the liquid column when the temperature is $0\,^{\circ}\text{C}$. State the apparatus he needs to do this and explain how he uses his apparatus. You may use a diagram if you wish.
(b)[2]
He measures the length of the liquid column when the temperature is $100\,^{\circ}\text{C}$. State the apparatus he needs to do this and explain how he uses his apparatus. You may use a diagram if you wish.
(c)[2]
Suggest how he then uses his thermometer to determine room temperature.