In this lab, we figured out how much energy (in calories) was contained in three different foods: a cashew, pecan, and cheesepuff. We did so by placing each piece of food on a paper clip and lighting it on fire. On top of the burning food we placed a tin can, and on top of the can, a flask of water with a thermometer inside. Since the water reached its maximum temperature after the piece of food burned entirely, we recorded the thermometer reading after the flame went out. Using the mass of the water samples, the specific heat of water, and each change in temperature of the water to figure out the calories contained in the foods.
Before setting this poor cashew on fire:
While this cashew is on fire, burning slowly and peacefully:
Data:
Burnt food:
Alison and I:
Questions:
1) Did you measure a temperature change in the food sample or the water?
As there is no way to directly measure the temperature of a food sample, we measured the change in the water instead. This served the purpose of finding the change in temperature of the food.
2) Did you measure the energy released by the food sample or the energy gained by the water?
The energy released by the food sample is actually the same as the energy absorbed or gained by the water. By measuring the change in temperature of the the water, we were also measuring the energy released by the food.
3) What happens to the small amount of energy that is not absorbed by the water?
The energy that was not absorbed by the water could've escaped through the holes in the tin can. In this expense of energy, there wasn't a completely effective transfer, as some of the heat released by the food was not absorbed by the water.
4) Were you surprised by any of the results? Explain.
I was not severely surprised by any of the results, but I found it interesting that the nuts contained more energy than the cheesepuff. It seems more intuitive to think that a cheesepuff has more Calories, or the "unhealthy stuff" as we know them to be, than healthy nuts.
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