Lab 11B: Calories in Food Lab

In this lab, my lab partner Meghana and I found the amount of calories in various food items (a cashew, pecan, and cheese-puff) by burning them and keeping track of the heat released. We built a makeshift calorimeter with a paper clip to hold the food item, a tin can to insulate the reaction and prevent heat loss, and a water-filled flask in which the heat lost by the food item was gained by the water. Each food item burned, which released heat, and the water absorbed the heat, causing the temperature to change, and this change in temperature was used to calculate the amount of energy in the food, and then the calories in the food.

1. Did you measure a temperature change in the food sample or the water?

We measured a temperature change in the water. Since the water absorbs all the heat released by the food sample, we knew that the heat released would be equal to the heat gained. Therefore, we were able to call the change in temperature of the water the change in temperature of the food sample as well. 

2. Did you measure the energy released by the food sample or the energy gained by the water?

We measured the energy released by the food sample because in the calculation, we plugged in the food's mass into q = mc(change in)T. However, since the energy released by the food sample was gained by the water, one could say we also calculated the energy gained by the water.

3. What happens to the small amount of energy that is not absorbed by the water?

The small amount of energy that was not absorbed by the water could have not been released by the food sample or could have escaped through the vent holes in the tin can.

4. Were you surprised by any of the results? Explain.

I was surprised that the cheese-puff had less Calories per gram than the nuts do. I always thought that cheese-puffs had a lot of Calories. Now, I can buy cheese-puffs and eat them more often than I eat nuts without feeling bad about my health.