Caloric Content of Food
The purpose of this lab was to measure the energy content of three different food items using the change in water temperatures from the heat of the food. Another purpose was to take the information acquired and become familiar with energy units used in food such as calories and joules. Procedure: The first step in this experiment was to weigh and record an empty 100mL beaker. Then fill the beaker approximately halfway, weigh it and record the weight. Record the weight of the water in the beaker. Place a piece of aluminum foil on a tabletop. Place a wire burner stand with the beaker full of water in the center of the aluminum foil and place a candle next to the rack. Measure the weight of one marshmallow and the weight of one fork. Record both measurements. Then place the marshmallow on the fork measure and record the weight of the marshmallow and fork together. That weight should equal the measurements of the fork and marshmallow combined in the previous measurement. Measure and record the temperature of the water in Celsius and record it.
Light a candle. Put the fork with the marshmallow over the candle flame. Remove the marshmallow from the flame right after it sets on fire and place it under the beaker of water. Hold it under the water until it is completely done burning. Make sure to stir the water frequently with the thermometer. When the marshmallow has burned down as much as possible, remove from underwater and record the temp of the water. Then record the weight of the fork with a leftover marshmallow on it. Subtract that measurement from the previous measurement of the fork with pre-burned marshmallow. Record the measurement of the marshmallow residue. Clean out the beaker of water and repeat the experiment with two other foods. Pick the appropriate tools to hold the food over an open flame. Make sure to clean out the beaker and reweigh before each experiment.
Experimental Results & Discussion of Observations
Table 1
| Food Item | Initial Mass of food & holder | Final Mass of food and holder | Mass of food burnt | Mass of beaker |
| Marshmallow | 43g | 41g | 1. 0g | 51. 5g |
| Peanut | 27. 5g | 26. 5g | 0. 0g | 51. 5g |
| Potato chip | 27. 9g | 26. 8g | 0. 3g | 51. 5g |
| Food Item | Mass of beaker and water | Mass of water | Initial water temperature | Final water temperature | Delta T (0C change) |
| Marshmallow | 102. 3g | 50. g | 250C | 350C | 100C |
| Peanut | 95. 7g | 44. 2g | 190C | 470C | 280C |
| Potato chip | 94. 5g | 43. 0g | 190C | 360C | 170C |
| Food Item | |
| Marshmallow | 1063J/g = 254 calories = . 254 Cal/g |
| Peanut | 5178J/g = 1238 calories = 1. 2 Cal/g |
| Potato chip | 2040J/g = 488 calories = . 49 Cal/g |
Additional Questions
- Read p. 244 or section 8. 3 of your textbook, then explain the type of reaction must have taken place in your calorimeter. A combustion reaction must have happened. The food turned into a gas and reacted to oxygen.
- What were the reactants of this reaction? What were the products? The reactants were then cooked foods and the products were the energy and heat.
- Where did the products go? The products or food mixed into the air and created smoke and odor that was released.
- Where are the potential areas for error in this experiment? This question is referring to errors inherent to the experiment, not the experimenter’s mistakes or lack of skills. Errors could be different products used, time to bring the products to a flame, and put under the beaker which would cause a different temperature change in the beaker from initial to final.
