Food Energy

Problem: What type of nut will generate the most energy in the form of heat and burn more kilocalories per gram of substance, a peanut or a walnut?
Hypothesis: If I burn walnuts and peanuts, then I expect the walnuts to burn the most kilocalories per gram, because in reviewing caloric statistics, walnuts contain more calories than peanuts, thus there is more energy to burn.
Procedure: Wear a lab apron and safety goggles, tie back long hair, and roll up long, loose sleeves. Be careful with matches and around fire. Also be weary of items in and around the apparatus that may become very hot during experimentation. Use pot holders when handling these objects.
The control is we are burning substances in the same environment, using the same apparatus and method of temperature taking. The variable is that we are burning two different types of nuts: walnuts and peanuts.
1. Assign roles to team members.
2. Prepare a table in which to record results.
3. Using the balance, determine the mass to the nearest 0.1g of each peanut and each walnut half. Record the masses in the table.
4. Obtain a 250-mL flask, a can, a cork with sample holder, and a piece of heavy-duty aluminum foil. Use equipment to make a calorimeter. Practice assembling and disassembling the equipment.
5. With the calorimeter disassembled, measure 50 mL of tap water and pour it into the flask.
6. Set the thermometer in the flask.
7. Measure the temperature of the water, and record it in the table
8. Place a peanut in the wire holder anchored in the cork. Then place the cork on the piece of aluminum foil.
9. Carefully set fire to the peanut. This may require several matches. Discard burned matches in the container of water.
10. Place the can over the burning sample with the viewing hole facing you. Place the flask of water on top of the can.
11. Take temperature readings as soon as the sample has burned out and then at 30-second intervals until the water temperature begins to decrease. (The temperature will continue to rise after the sample has burned out as the water absorbs heat from the can.)
12. Allow the calorimeter to cool about 2 minutes before disassembling.
13. Repeat steps 5-12 until you have data for three samples each of a peanut and walnut half. Change the water in the flask each time.
14. Wash your hands thoroughly before leaving the laboratory.
Analysis:
1. See the graph and data table for all calculations.
2. For the peanuts: the sheet I was given by my teacher says that there are about 584 kilocalories per 100 grams of peanuts, although the class’ results said that there were only about 215 kilocalories per 100 grams of peanuts. For the walnuts: the sheet I was given by my teacher said that there are about 630 kilocalories per 100 grams of walnuts, although the class’ results said that there were only about 269 kilocalories per 100 grams of walnuts. The class results were tremendously lower for both types of nuts by about half. I got these figures by converting on the sheet from ounces to grams, and then I had to reduce the figure I got so the number of calories would fit together for 100 grams.
3. I can account for any differences by saying that some heat energy may have escaped out of the testing apparatus, and not have gone into the beaker of water like it should have. This is very likely because our testing environment was not as controlled as it ordinarily would be in an experiment of this type.
4. I would expect the energy release of the burning of cells in the human body to be greater than that of the nuts because living organisms contain more energy than nonliving ones, thus there is more energy to give off in a living cell. I would also expect the burning of cells in the human body to release more energy than a published chart with foods having the same caloric content, because the cells of the human body contain many ATP nucleotides, necessary for bodily processes, which contain an abundance of energy.
5. According to the class’ average results, the walnut seemed to be a better source of energy because 2.69 kcal./g were burned in the walnut, and only 2.13 kcal./g were burned in the peanut.
6. There may be more ATP nucleotides containing energy in a substance with few kilocalories, and thus a lot of energy, and another substance with many kilocalories, but few ATP nucleotides, and thus a small amount of energy.
7. The original source of energy in all the foods tested was the kilocalories inside the food and the ATP, energy holding nucleotides inside the foods.

Conclusion:
By examining the results of this experiment, I can conclude that the burning of walnuts releases more energy than the burning of peanuts because the walnuts burned a larger number of kilocalories per gram of substance than the peanuts did. The class’ results revealed that the walnuts burned on average 2.69 kcal./g whereas the peanuts only burned 2.15 kcal./g on average. Walnuts are a better source of energy than peanuts.