Marcy and her brother each brought a burrito to a family picnic. The burritos were identical, but one was in a metal lunchbox and one was in a plastic lunchbox. This table shows how the temperature of each burrito changed over 2hours.

Question

Burrito Initial temperature (°C) Final temperature (°C)
Burrito in the metal lunchbox 77 31
Burrito in the plastic lunchbox 78 40
The next time Marcy brings a burrito to a picnic, she does not want it to cool down quickly. What should she do to minimize the rate of thermal energy transfer out of the burrito?
use the metal lunch box
use the plastic lunch box
either the rate of thermal energy transfer is the same whether the lunch box is plastic or metal

Answer 1

To minimize the rate of thermal energy transfer and slow down how quickly the burrito cools down, Marcy should use the plastic lunch box.

From the table, we can see that the burrito in the metal lunchbox cooled down from 77°C to 31°C, while the burrito in the plastic lunchbox went from 78°C to 40°C. The plastic lunchbox allowed the burrito to retain heat better, as indicated by its higher final temperature compared to the metal lunchbox.

In general, because metal is a better conductor of heat than plastic, it allows for faster heat transfer, leading to quicker cooling. Therefore, for better insulation and to retain heat, the plastic lunchbox is the better choice.