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1 Physical Science CHEMISTRY () S C I E N C E C H E M I S T R Y This Enrichment4You e-guide provides a brief overview of energy in food. In this e-guide you will: *Learn Basic Information About Calculating Calories in Food *Conduct an Experiment To Determine the Calories in Food Using a Simple Homemade Calorimetry Device ENRICHMENT4YOU Published by Henrich Incorporated Copyright 2005 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form by any means, electronic, mechanical, photocopying or otherwise, without first obtaining the written permission of the copyright owner. Physical Science Chemistry)

2 Physical Science CHEMISTRY () INTRODUCTION The purpose of this Enrichment4You e-guide is to give a brief introduction to how scientists determine the amount of energy there is in particular foods. You will read a brief overview of how calories in food are determined and follow a stepby-step presentation with photographs on how to make a calorimetry device and conduct an experiment using the apparatus. 1. Learn Basic Information About and How Calories Are Calculated- Pages Conduct an Experiment to Determine the by Making a Homemade Calorimetry Device - Pages Physical Science Chemistry)

3 Physical Science CHEMISTRY () Did You Know??? Joules is a common unit of energy used in the physical sciences. A Brief Overview All living creatures require food to live. Food is used by the body as fuel or energy. The amount of energy a food item has is describe as calories or kilocalories or kilojoules. A single calorie is a single unit of energy. Basically, a calorie is the amount of energy it takes to raise the temperature of 1 gram of water by 1 degree Celsius or 1.8 degree Fahrenheit. One calorie is equivalent to joules or rounded up, 4.2 joules. So 3 calories would be joules or rounded up 12.6 joules. Physical Science Chemistry) 1 As the body consumes food, some of the potential energy value of the fuel may be lost through digestion and metabolism. Scientist and nutritionists use a tool called a bomb calorimeter to help them determine the potential energy value in particular foods. The energy value for each macronutrient must be known, and an allowance made for body losses, such as digestion.

4 Physical Science CHEMISTRY () DID YOU KNOW??? We commonly associate only food with calories, but calories can be in anything that might contain energy. For example a single gallon of gasoline contains approximately 31,000,000 calories. With this many calories you drive an average car about 20 miles. A macronutrient is a substance such as a mineral or vitamin that is necessary only in small amounts to insure the proper growth and metabolism of a living creature. Some food have higher energy values than others. Fat for example is a very dense macronutrient. The amount of macronutrients of a particular type of food determines its food value. If you were going to make a list of the food value/ energy based on the macronutrients of different foods the foods would be listed as follows: fat alcohol proteins carbohydrates You will notice that dietary fiber is not usually given an energy value for humans nor do vitamins or elements which are calorie free. Each individual processes food in basically the same way - through digestion, but not everyone requires the same amount of food to maintain life. Our size, age, and health all affect how we process or use the energy in food. When we eat more food than we are using up through exercise, the body stores the excess as fat, resulting in weight gain. Physical Science Chemistry) 2

5 Physical Science CHEMISTRY () BURN THAT FAT Actually our bodies do burn calories through our metabolic processes. This is when enzymes break the carbohydrates into glucose (sugar), fats into glycerol and fatty acids, and the proteins into amino acids which are then used by our bodies as energy. When we look at a food label to determine the number of calories what we are looking at is really kilocalories (1000 calories = 1 kilocalorie. Thus an item that has 100 food calories is really 100,000 calories. To give you an idea of calories in food: One gram of fat has 9 calories One gram of protein has 4 calories One gram of carbohydrates has 4 calories Most foods are a combination of the above. If you know how many fats, proteins or carbohydrates a food has you will be able to calculate the number of calories the food has. By law, food manufacturers must provide a nutritional label on the food container in the United State. Food manufactures are able to determine the number of calories through burning or using a process called Calorimetry. Lets pretend that one marshmallow has 25 food calories, this actually means that if that marshmallow was set on fire and completely consumed by the fire it would have produced 25 kilocalories or food calories. This mean that 25 grams of water was raised 1 degree Celsius. Looking at the nutrition label again, we observe that the marshmallow contains 1 gram of fat, 1 gram of protein and 3 grams of carbohydrates equalling 25 calories. Using the information above you would compute the break down as follows: 9 calories come from fat (9 cal x 1 g) 4 calories come from protein (4 cal x 1 g) 12 calories come from carbohydrates (4 cal x 3 g) Total 25 calories raised 25 grams of water 1 degree Celsius Physical Science Chemistry) 3

6 Physical Science CHEMISTRY () Conduct an Experiment to Determine the by Making a Homemade Calorimetry Device c2005 Henrich Inc. Calorimetry is a technique to determine the amount of calories in food through burning and observing how much heat it produces. Calorimetry is an the experimental method used to investigate heat flow. In this experiment you will find the different calories of some everyday foods. This experiment will only estimate the number of calories. To get a more accurate value it would be necessary to have highly precise and expensive test equipment and a controlled environment. Even with these limitations, this experiment is very interesting and demonstrates the basic scientific process that companies use to determine calories and nutritional information for food labels. Physical Science Chemistry) 4 MATERIALS: *Test Foods - mini marshmallow, peanut, cereal item, etc. *Test tube (18 x 150 mm) *Balance - electronic balance is preferred to get accurate readings (you can sometime check these out at local libraries or public schools) *A way to measure milliliters or measuring spoons *Wire grid fabric 1/2 squares *Pegboard hook, screw driver holder or other device to hold test tube *Wire cutters *Gloves *Large cork with wire *Submersible and heatproof thermometer *Water *Copy machine