In this lab we found the number of Calories per gram of different food items using a calorimeter. Each piece of food (a cashew, pecan or cheese puff) was lit on fire and covered with a tin can. The tin can "stove" heated up a flask of water and a change in water temperature was recorded using a thermometer. By using the mass of the food burned, the change in water temperature, and the specific heat of water, we were able to calculate the Calories per gram of each food type.
1. Since it isn't possible to directly measure the temperature change of a food item, we measured the temperature change of the water. The amount of heat absorbed by the water in the flask is equivalent to the amount of heat given off by the burning food, therefore we know the temperature change of the water would be equivalent to the temperature change of the burning food sample.
2. The energy released by the food sample was gained by the water, therefore we measured the same amount of energy for both the food and the water.
3. The small amount of energy that was not absorbed by the water escaped into its surroundings. The glass flask or tin can may have absorbed some energy, while some energy may have also escaped through the holes of the tin can into the air.
4. I was surprised that the nuts contained more Calories than the cheese puffs because I have always been told that "unhealthy foods" contain more Calories than "healthy foods", but this lab challenged my knowledge of Calories in comparison to healthiness. I also was surprised that cheese puffs had a higher Calories/gram compared to the nuts because I didn't process how the mass of large cheese puffs are still light compared to a small nuts.
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