National Chemistry Week (NCW) began in 1987 as National Chemistry Day, and it is a great way to encourage students to learn chemistry. Annual themes help give direction and variety to the celebration each year. This year, National Chemistry Week will take place Oct 19–25, and the theme is “The Sweet Side of Chemistry—Candy.”
Celebrate National Chemistry Week with an experiment that investigates the energy content in various food items, such as cashews, marshmallows, peanuts, and popcorn. In Experiment 16, “Energy Content of Foods” from Chemistry with Vernier, students use a Stainless Steel Temperature Probe to determine the energy released (in kJ/g) as the various foods burn. For an inquiry version, check out Experiment 6, “Investigating the Energy Content of Foods” from Investigating Chemistry through Inquiry. In addition to the food items listed, students can explore the energy content in chocolate and non-chocolate candies. Students can look at different types of candies for patterns in the amounts of energy released.
Not all candies contain the same amount of energy. The quantity of energy stored in the candy will vary, based on the amounts of sugar, fat, and protein. Food labels list the energy in units of Calories. The large calorie or food calorie (Cal) is the amount of energy needed to increase the temperature of 1 kg of water by 1°C, and there are 4.184 kJ in one Calorie.
As an added bonus for this experiment, show your students the “Combustion of a Peanut M&M®” video available in the Sample Movies folder in Logger Pro 3. This video demonstrates the difference in food calories between the sugar coating (4 Cal/g), the fat (9 Cal/g), and protein (4 Cal/g) in a peanut M&M. A peanut M&M is dropped into molten potassium chlorate with a thermocouple located near the melt. When the M&M hits the oxidizing agent, the candy ignites and the temperature goes up and then plateaus. However, once the sugar is burned off, the temperature shoots up again due to the difference in heat of combustion between fat and carbohydrate.
Tell us how you celebrate National Chemistry Week using Vernier probeware. Email us at email@example.com