Science Buddies: "Ask an Expert"

When conducting your experiment entitled "Burning Calories: How much energy is stored in different types of food?", the findings of our results seem to have WAY too many calories per gram of water when using your equation Qwater=mc(triangle)T. For ex., the cashew that we burned has a total of 4200 calories. The initial water temperature was 18 degrees C, and after we burned the cashew, the water temp. was 60 degrees C. This leaves a difference of 42 degrees C. Therefore, after working the equation, a cashew contains 4200 calories. This CANNOT be. Please advise us on what we need to do or if we are making an error somewhere?? PLEASE ANSWER IMMEDIATELY!!! we NEED to get this project FINALIZED!!!!!! Thanks

Hi,

Your result of 4200 calories (small calories) for burning one cashew does not seem extremely out of line. Remember that food calories are measured in Calories (1000 calories = 1 Calorie = 1 kilocalorie). My cookbook says 6 to 8 cashews have 88 Calories, so one cashew completely burned should be about 11 Calories. Since you probably did not completely burn the cashew, your result of about 4.2 Calories per cashew actually looks quite reasonable. Just be mindful of the unit definitions!

Best regards,

Barrrett Tomlinson