Push the eye of a needle into a small cork and the other end of the needle into a shelled peanut. Use a can opener to remove the two ends of a large juice can. Use a hammer to punch holes around the bottom of the large juice can. Remove the top of a small can. Use a hammer to punch holes around the top of the small can. Push a barbecue skewer through the holes of the small can. Fill the can with 1/2 cup of room temperature water. Light the peanut with a match or lighter. Place the nut inside the large can. Place the small can above the nut by balancing the small can inside the large can. Let the nut burn out. Use a thermometer to record the water temperature change.
Burn more than one peanut to heat the water to a higher temperature. Try the experiment using different types of peanuts, including dry roasted, raw or freeze dried. Use different types of nuts to measure the difference between the heat energy in a peanut and the heat energy in cashews, walnuts, pecans or other types of nuts. You will need extra needles to attempt variations of the heating the peanut experiment.
One BTU is defined as 252 calories. These are International Table calories, which are equal to 1,000 of the "kilocalories" we use for measuring food energy. A kilocalorie is a unit of energy often associated with food. Divide 252 by 1,000 to get 0.252, the number of kilocalories in a BTU. Multiply 0.252 by the number of BTUs in the peanut to calculate the number of kilocalories in the peanut. Multiply that number by 1,000 to obtain the number of calories in the peanut.
Calculate the energy in the peanut in terms of British Thermal Units (BTU). Weigh the small can with nothing in it. Weigh the can with 1/2 cup water in it. Note the temperature after the peanut heats the water. One BTU raises the temperature of 1 pound of water or a pint of water 1 degree Fahrenheit. There are two cups or four half-cups in a pint. So, one BTU should raise the 1/2 cup of water 4 degrees Fahrenheit. If the water temperature increased 10 degrees, divide 10 by 4, which means the peanut had 2.5 BTU.