Why do we need an air gap between the calorimeter cups and a lid?

Air is a poor heat conductor; therefore, it and the calorimeter cover are used to keep heat longer and to reduce heat loss (decrease in thermal conductivity) between the contents of the calorimeter and the environment.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.