Food as Energy Section B Intro to Lab Activity B.1

Food as Energy All human activity requires All human activity requires Burning food for energy Burning food for energy Not really burned Not really burned Energy is released by chemical rxns Energy is released by chemical rxns How can we Tell?? How can we Tell??

Figuring how much energy… How to determine amount of energy How to determine amount of energy 1. Burn a known amount of food 2. Carefully measure quantity of thermal energy released =CALORIMETRY Calorimeter is the device we use!!! Calorimeter is the device we use!!!

Units of Energy calorie calorie Thermal energy needed to raise the temp. of 1 gram of water 1 degree Celsius Thermal energy needed to raise the temp. of 1 gram of water 1 degree Celsius Calorie Calorie 1000 calories 1000 calories Increases the temperature of 1kg of water by 1 degree Celsius Increases the temperature of 1kg of water by 1 degree Celsius 1,000 calories (cal) = 1 kilocalorie(kcal) = 1 Calorie (Cal)

Importance of Calories Nutritionists Nutritionists Count Calories Count Calories Dieting Dieting Comparing foods Comparing foods

Where does food energy originate? All food energy comes from sunlight All food energy comes from sunlight Plants capture solar energy Plants capture solar energy Make large energy rich molecules Make large energy rich molecules Energy converted to chemical energy Energy converted to chemical energy We recover this energy when we eat plants or animals that eat these plants We recover this energy when we eat plants or animals that eat these plants

So Why is this all Important? Determine energy given off by a peanut when it burns Determine energy given off by a peanut when it burns Oil in peanuts burns fast when Oil in peanuts burns fast when Your peanut will heat a known mass of water Your peanut will heat a known mass of water You will measure the temp of the water before and after You will measure the temp of the water before and after Then you will calculate the thermal energy Then you will calculate the thermal energy From that we can determine the calories in that peanut!! From that we can determine the calories in that peanut!!

Page Food Energy in A Peanut