Seventh grade scientists “burn” calories in walnut and marshmallow lab

As seventh grade students study chemical reactions in human cells, they learned about how nutrients in foods are transformed into energy. We most often hear about calories corresponding with energy, so this unit led students to understand that a calorie is a unit of measurement for heat energy. Higher calorie foods create more heat energy than lower calorie foods, so students set out to learn which food has more calories- walnuts or marshmallows.
To evaluate whether walnuts or marshmallows have more calories, students held the burning foods under test tubes of water. Students carefully observed the thermometers in the water to measure temperature increase. The temperature increase represents increased heat energy and therefore a higher calorie count in the food.

As the marshmallows and walnuts burned, students observed with all five senses- they watched the flames consume the food and increase the temperature, and they smelled the traces of smoke from the burning food. They heard moderate crackling as the foods heated up, and even if they didn’t get to taste the foods, many dreamed of toasted marshmallows and s’mores. Plus, students observed the sticky texture of a burnt marshmallow as they cleaned up their lab stations.

While seventh grade students do not often “count calories,” they did admit that the lab helped them understand that eating healthy does usually leave them feeling energized for longer periods of time.

Well done, seventh grade scientists and nutritionists!