Biology students ignite Cheetos to learn about calories in food.
Food supplies energy for all animals. Without it, we would not live. The quantity of energy stored in food is of great interest to humans because your body needs energy to run, talk, and think which comes from the foods you eat. Not all foods contain the same amount of energy, and not all foods are equally nutritious. An average person should consume approximately 2,000 kilocalories per day.
In science, energy is often measured in calories. A calorie is the amount of heat energy needed to raise one gram of water one degree Celsius. The amount of energy found in food is measured in kilocalories (symbolized by "C" or called calories). So, if a candy bar says it has 180 calories, it really means it has 180,000 calories. Yikes!
One method scientists use to determine the number of calories found in food is by a calorimeter. This method usually involves burning samples of food and measuring a temperature change in a designated amount of water. This is exactly what ninth-grade students did today in Dr. Brandon Noel’s biology classes.
The girls used a makeshift calorimeter by filling empty soda cans with 20 mL of water and burning Cheetos (a not-so-healthy snack). The girls were required to do multiple trials and were sure to weigh the Cheeto prior to burning and then again immediately after burning. Prior to burning the Cheeto, the girls measured the initial temperature of water. Afterward, the girls measured the final temperature so they could determine a change in temperature during the process.
“An added bonus to this lab is the interdisciplinary approach,” Noel says. “The girls are also required to incorporate algebraic formulas to analyze their data.” They must deal with the specific heat of water (a constant), but use a formula q = mc (Tf - Ti). Girls have some of these data, but not all, and have an opportunity to use mathematical formulas to complete calculations, which will guide them to answer questions at the end of their lab.
“As the girls continue to learn more about cellular respiration, they will understand that our bodies are doing this consistently to obtain energy from the foods we eat,” Noel says. “The girls really seem to enjoy this particular lab because they are not only getting a chance to burn a favorite food, but they are also learning about one of the ways our cells go about gathering energy from the foods we eat—a process known as cellular respiration.”