Name: ______________________________ Period: ____
FOOD ENERGY LAB
Have you ever counted Calories?
Food energy is measured in Calories (upper case C)
• It takes 1000 calories to make up a Calorie (kilocalorie=kcal)
Example: A standard French fry serving contains 220 Calories of food energy.
How many calories are present?
220 Calories x 1000 cal/Cal. = 220,000 calories
Heat is a form of energy that can be measured as temperature and expressed in units called
calories. It takes 1 calorie (cal) to raise the temperature of 1 g of water 1C
Simplified formula may be used: calories = grams of water x (final C – initial C)
This is determined by the burning of food under controlled conditions (calorimetry) using
an instrument called a calorimeter.
Problems:
1. You want to raise the temperature of 250mL of water from 22 C to 99 C. How much
thermal energy will be needed?
Use equation calories = grams of water x (final C – initial C)
(for all practical purposes the density of water is 1 gram/mL)
2. How much thermal energy will be needed to raise 4 containers of the above water
under the same conditions?
1
EXPERIMENT: FOOD CALORIES
Materials:
 Cheese puff
 (1) Large can
 (1) Small aluminum can
 100 mL graduated cylinder
 Tap water
 Small tin dish
 (1) Small paint brush
 Cork







Paper clip wire
Electronic balance
(1) Weighing boat
(1) Glass stirring rod
Matches
Thermometer
Calculator
Procedure
1. Place a weighing boat onto the electronic balance.
2. Obtain a cheese puff place it into the weighing boat. Record its mass (g) in the Data
Table on the next page. Don’t forget to first zero out the mass of the weighing boat…
3. The large can that has both ends removed will serve as a chimney to minimize heat loss
during the experiment.
4. Take your graduated cylinder and measure 100 mL of tap water.
5. Pour the 100 mL of tap water into the small aluminum can that has one end removed
and two holes punched in the sides of the can near the top. The holes should be
opposite each other.
6. Record the temperature in C of the water in the can in the Data Table on the next
page.
7. Insert a glass stirring rod through the holes in the sides of the aluminum can. Use the
rod to balance the small can within the large can.
8. Place the cheese puff (assembled by inserting one end of the wire into a cork and the
other into the cheese puff, as shown below) on a nonflammable tin surface (one has
been provided for you), and ignite it with a match. Immediately place the large can with
the aluminum can of water balanced in it over the burning puff. The aluminum can
containing the water is now above the puff.
2
9. Allow the puff to burn until it goes out.
10. Record the water’s highest temperature in C in the Data Table below.
11. Carefully remove the cans from above the charred remains above the cheese puff.
12. Brush the charred puff remains into a weighing boat and record the mass (g) of charred
puff in the Data Table below. Don’t forget to first zero out the mass of the weighing
boat…
13. Complete the ‘Calculations and Questions’ section.
NOTE: measuring calories in this manner does not take into consideration differences in
digestibility of different substances (i.e. starch vs. cellulose), or the way in which different
substances are metabolized (lipid vs. carbohydrate vs. protein)
CALCULATIONS AND QUESTIONS
1. Calculate the calories of heat from the burning puff. The 100 mL water has a mass of
100 g (for all practical purposes the density of water is 1 gram/mL) and the specific heat
of water is one calorie/degree Celsius/gram (1 calorie/gram C). Use the following
equation to make the calculation.
calories = grams of water x temperature change x specific heat of water
2. Divide the calories from question 1 by the change in mass of the puff. This determines
the calories released per gram of puff burned. Record your answer in Kcal or Calories.
3
3. Multiply the measured Calories by the number of grams in a serving size, obtained from
nutritional panel to obtain Calories per 1 cheese puff.
4. Compare your Calorie results to the nutritional panel.
Your Calorie results
Nutritional panel results
5. Calculate your actual Calories per serving.
({Nutritional results – your measured Calories per cheese puff}/ nutritional results) x 100
=actual Calories per serving
6. Why do you suppose the calculated values for Calories per gram are less than the actual
values listed?
4
7. Colin is a sixteen year-old male who weighs 165 pounds. He has just consumed a Bacon
McDouble burger (400 Calories), a small fry (230 Calories), and a medium Coke (200
Calories). Using the information and equations given below, calculate how any calories
Colin will burn of the food energy from what he has consumed playing basketball,
racquetball, and volleyball for a period of 30 minutes each.
The following chart gives the approximate number of calories burned per minute of a
variety of activities.
For each activity, multiply your exact weight by the number in the per pound column to
equal the number of calories burned per minute. Multiply this number by the number of
minutes in that activity to equal total calories burned.
EXAMPLE: Calories burned per pound per minute (badminton - 044) x (times) Colin’s
exact weight (165 pounds) = (equals) total calories burned per minute (7.26 calories
burned per minute) x (times) minutes of activity (30 minutes) = (equals) 217.80
total calories burned per activity.
Activity (alphabetical)
calories
Your
Total
Minutes
burned per
exact
calories
of
pound per weight in burned per activity
minute
pounds
minute
Basketball
.063
Racquetball
.081
Volleyball
.023
Total
calories
burned
Grand total of calories burned
8. Did Colin burn all of the calories that he consumed after he completed his hour and a
half of activities? ___________ Justify your answer below mathematically.
9. What life process(es) enabled Colin to burn the calories during the activities? You may
have to refer back to information from Chapter 1.
5