Final answer:
Dr. Bunce was applying Gay-Lussac's Law, which describes the proportional relationship between the pressure and temperature of a gas when its volume is constant.
Step-by-step explanation:
Given the description, Dr. Bunce is dealing with a scenario where the pressure of a gas needs to be calculated based on a change in temperature while keeping the volume constant. This scenario directly relates to Gay-Lussac's Law, as it describes the relationship between the pressure and temperature of a gas when the volume is not allowed to change. Gay-Lussac's Law states that for a given amount of gas held at constant volume, the pressure is proportional to the absolute temperature. This law is particularly applicable in cases where the volume is fixed and only temperature and pressure vary. Therefore, when Dr. Bunce was doing calculations for which temperature would result in enough pressure to push the pop-up timer up, she was applying Gay-Lussac's Law.