How Much Energy is in Food?
How does the type and amount of food I eat
affect the energy I get?
Chemical
reactions result
in energy
changes.
Ryan L. Hackl
Spiritwood High
School
Foods include
chemical
bonds.
The foods I eat
will affect the
energy I
need/use.
1. Can we calculate how much energy we eat in our foods?
2. How do food companies determine the amount of energy in our
foods?
Technology and Learning
Living Sky School Division
Fall 2010
Chemistry 30
(Energy
Changes)
DEFINING THE DESTINATION:
UbD Stage One – What do we want them to learn?
Outcomes:
1. Students will associate calorimeter work with energy content in foods.
2. Students will compare/contrast energy contents of various meals.
Understandings:
1. Chemical reactions result in energy
changes.
2. Foods are made of chemical bonds.
3. The foods I eat will affect the energy I
need/use.
Essential Question:
How does the type and amount of food I eat affect
the energy I get?
Knowledge:
Preknowledge:
o
o
o
Determining enthalpy of substances and
using ‘kilojoules’ to measure this (Q =
mcΔT)
Differences between temperature and heat
Using the ‘Percent Error’ formula
Do:
o
o
Students will perform the calorimetry lab
Students will create a poster to show the
healthy meal for an athlete
Knowledge:
o
o
o
Students will perform calculations using
Q=mcΔT
Students will interpret nutritional
information from fast food websites
Students will create a food plan for an
athlete
EVIDENCE OF UNDERSTANDING
UbD Stage Two – How will we determine what they know?
Assessment:
Performance Task
o Perform the calorimetry lab to determine
the heat content in potato chips
o Locate nutritional information from fast
food websites
o Compare and contrast different
sandwiches/foods from fast food
companies
o Compare traditional meals with fast food
meals
Other Evidence:
o Summary question for peer interaction
(using Q=mcΔT)
LEARNING PLAN
UbD Stage Three – How will we teach?
Example Formats:
One
Three
Activate
o why are marathon runners advised to eat a
large plate of pasta before running a race?
o why do hummingbirds eat so much sugaryfood?
o how much more food energy would you get if
you had a high fat vs high protein vs high
carbohydrate diet?
o Is ‘Subway’ food more healthy than
‘McDonalds’?
Where
o Science Lab: calorimetry lab
o Computer Lab (or laptops): locate nutritional
information and create a poster / blog
Acquire
o Perform the calorimetry lab to find the heat
content of chips
o Use ‘Percent Error’ to compare nutritional
information on packaging with experimental
results
o Use a laptop to locate nutritional information
from fast food restaurants (McDonalds, Burger
King, Subway, Wendy’s, etc)
Explore/Enable/Equip
o Collect and interpret nutritional information
o Research skills
o Compare energy content levels for various
foods (in meal preparation)
Apply
o Use Microsoft Publisher (or another desktop
publishing program) to create a poster to share
results
o (optional): Blog your results and/or present to
class
Exhibit/Evaluate
o Poster using Microsoft Publisher and/or blog
responses and/or present to class
o Plan a meal for an athlete
o Compare a typical meal for an athlete with a
more sedentary lifestyle
Two
Lesson Focus
o Skill development
Assessment
o Compare energy content from various types of
potato chips
Learning Experiences
o Skill development (chemical) through using
science lab equipment
o Technology development using temperature
probe
o Research skills development using technology
to locate/interpret nutritional information
Hook
o Raise an ‘activate’ question
o Watch video showing endurance runner
o Show bags of potato chips (used for calorimetry
experiment)
Rethink/Reflect
o Share results with class (or blog post) and
collect responses
Calorimetry Lab
“The Energy in Foods”
Objective:
To determine the energy content in different potato chips.
Introduction:
Why are marathon runners often asked to eat a plate of pasta before a major ‘meet’? The answer
is that pasta is a good source of energy (or fuel) for the body. All foods are made of chemical
bonds, and when we eat food, our bodies break down the bonds in the food to give us energy.
The more complex the food (like potato chips), the more energy there is for our body to use. But
how much energy is there in a potato chip?
We can answer that question by using a calorimeter similar to the following to burn potato chips.
The big idea?
The amount of heat we lose by burning the potato chips is the same as the amount of
heat we gain (and can measure) by heating the water.
In formula form, this means:
Qlost by food = Qgained by water
Materials:


Graduated cylinder
Cork with wire attached




Calorimeter
Lighter

Water
Thermometer (or
temperature probe)
Forceps

Safety glasses

Potato chips (at least 2
different brands)

Digital scale

Petri dish or weigh boat

Procedure:
1. Choose two brands of potato chips, and hypothesize which brand has more heat content
(“energy”). Record your hypothesis in the observations table.
2. Using the petri dish (or weigh boat), obtain about 10.0 grams of the potato chip, and record the
data in your table. Record this as “minitial” in your observation table.
3. Using the graduated cylinder, measure out 100 mL of water, and pour it into the calorimeter.
Since 1 mL = 1 g for water, record “100 g” for “mwater” in the observations table.
4. Measure the initial temperature of the water. Record this as “T1” in your observations table.
5. Place the potato chips on the cork-and-wire apparatus, so that the potato chips are very near to
the bottom of the calorimeter. (Refer to the picture in the introduction section).
6. Light the potato chips, and allow the chips to completely burn. Record the final mass of the ‘chip
remnants’ as “mfinal”
7. Now, stir the water in the calorimeter and measure the highest temperature reading. Record this
as “T2” in your observation table.
8. Repeat steps #2-7 for your second brand of potato chip.
9. Once completed, please clean up your work station, and put the cooled chip remnants in the
garbage.
Observations:
Hypothesis:
Which brand of potato chip has more energy? Why?
Table 1. Data recording sheet
1.
Mass of Potato Chips at start, in grams
(minitial)
2.
Mass of ‘chip remnants’, in grams
(mfinal)
3.
Mass of chips burned, in grams
mchips = mfinal - minitial
4.
Mass of water used, in grams
*see procedure #3
5.
Initial water temperature, in °C
(T1)
6.
Final water temperature, in °C
(T2)
7.
Change in water temperature, in °C
∆T = T2 – T1
Brand #1:
Brand #2:
________________
________________
Table 2. Calculations
Food #1:
Food #2:
________________
________________
4.18 J/ gC
4.18 J/ g C
1. Total mass of water used
(from Table 1, line 4)
2. Change in water temperature
(from Table 1, line 7)
3. Specific heat of water
4. Energy absorbed/lost by the water (J)
[use Q = mcT]
5. Energy absorbed/lost (kJ)
[convert J into kJ by ÷ 1000]
6. Mass of chips used
(from Table 1, line 3)
7. Calculate the kJ released per gram of food
used
[divide energy in kJ (part 5) by mass of chips
(part 6)]
8. What the potato chip package says for this food
Discussion Questions:
1. Calculate the Percent Error between your calculated energy value (Table 2, #7) and the actual
value from the potato package (Table 2, #8).
2. What in the potato chips made them burn so well?
3. Backpackers in the woods sometimes take a bag of chips as a ‘fire starter’. Based on your
experience with this lab, why is this a good choice?
4. In terms of energy, support/refute the following statement:
“Eating too many potato chips may make you less healthy, because you
are taking in too much energy.”
Choose either #5 or #6 or #7 and prepare a well-researched blog post or poster to highlight your
learnings:
5. Using the ‘Nutritional Information’ on the websites of various fast food restaurants, determine
the total energy eaten in a typical ‘full meal’ (drink, meal, dessert) for any four restaurants and
compare/contrast.
6. Contrast the energy value of a ‘traditional homecooked meal’ with that from a ‘fast-food
restaurant’. Include a sample meal from each, and the long-term outcomes associated with each.
7. Compare/contrast the energy and nutritional needs of an athlete with a regular person. Account
for the higher needs.