Explain why using a polystyrene cup gives more accurate results than using a glass beaker.

This experiment measures the temperature change of a reaction, a technique called calorimetry. A major source of inaccuracy in calorimetry is the loss of thermal energy to the surroundings. 1. **Polystyrene is a good thermal insulator:** This means it does not conduct heat well. 2. **Glass is a better thermal conductor:** It allows heat to pass through it more easily. By using a polystyrene cup, less heat from the exothermic reaction is lost to the air and the lab bench. This ensures that the measured temperature rise is as large as possible and therefore closer to the actual temperature change of the reaction, leading to a more accurate result.