1. Students conducted an experiment to measure the energy content of different foods by burning samples of marshmallow, bread, carrot, and meat and measuring the increase in temperature of water. 2. They calculated the energy gained by the water in Joules and the energy content of each food sample in Joules per gram. 3. The results showed that bread provided the most energy per gram, followed by meat, marshmallow, and carrot.

1. Brainstorm and make a list of foods that give
your body energy.
Think of different energy needs:
working out
taking a test
playing a sport
Nancy Dooley

2. Organisms
maintain a The result of these
dynamic responses is called
homeostasis, a
equilibrium “dynamic equilibrium Organisms have a diversity of
that sustains “or “steady state” homeostatic feedback
which keeps the mechanisms that detect
life internal environment deviations from the normal
within certain limits.
state and corrective actions to
return their systems to the
normal range
Life is dependent
upon availability of
an energy source and Responses to
raw materials that change can range
are used in the basic in complexity from These mechanisms
enzyme-controlled simple activation maintain the physical
biochemical of a cell chemical and chemical aspects
processes of living process to of the internal
organisms. elaborate learned environment within
behavior narrow limits that are
favorable for cell
activity.
Because they must
organisms are
continually
continually Failure of
monitor and these control
exposed to respond to
changes in these mechanisms
their external changes. can result in
and internal
environments disease or
even death.

4.  What foods give us the most energy?
 What type of food item:
protein, carbohydrate, fat?
 Give me an example of a protein?
Carbohydrate? Fat? Processed junk food?
 Choose some food items from the baskets to
experiment with.
 How could we measure the energy supply
that comes out of the food?
 Let me explain a way we can try to do this.

5. What supplies do we need?
Let’s review safety procedures for
dealing with fire?
Let’sget into our groups, collect
supplies, task cards, lab
books, lab guides
What challenges might we face
with this experiment?
TECHNOLOGY

6. Why did you choose the foods you
did and why do you think they
give our body the most energy?
Predictions
Predictions

7. Anyone ever hear of
the Food Pyramid?
Fat
Protein
Carbohydrates
How does our body work to break these
down? Does anyone remember the word
ENZYMES?

8. Some of your questions
Can we change food to make it healthier
Can this experiment help us choose
for us to eat? (follow up Genetic
healthier foods?
Engineering)
Think Think Think
Which foods have the greatest energy
What else effects our energy?
output?
Let’s analyze our data
How should we record our data? What might it tell us?

9. Marshmallow
Meat
Bread
Carrot

10. What have we found here?
Equations:
• Heat calories = Mass of H2O (g) x
Change in Temperature of the
water (C) x 4.18 J/g C
• Kilocalories = Heat calories (cal)
/ 1000 (cal/Kcal)
• Energy yield = Kilocalories (Kcal)
/ Grams of food (g)

11. Table 1
Measurements Sample 1 Sample 2 Sample 3 Sample 4
Food used Marshmallow Bread Carrot Meat
Mass of empty can (g) 20000g 20000g 20000g 20000g
Mass of can plus water (g) 65000g 65000g 65000g 65000g
Minimum temperature of water (°C) 20.8 C 22.2 C 23 C 22.6 C
Maximum temperature of water (°C) 49.6 C 42.1 C 33.9 C 60.2 C
Initial mass of food (g) 10000g 10000g 10000g 10000g
Final mass of food (g) 7500g 9000g 5000g 8000g
Table 2
Calculations Sample 1 Sample 2 Sample 3 Sample 4
Mass of water (g) 45000 45000 45000 45000
∆t of water (°C) 28.8 19.9 10.9 37.6
∆mass of food (g) 2500 1000 5000 2000
Energy gained by water (J) 5417280 J 3,743,190 J 490,500 J 1692000 J
Energy content of food (J/g) 2.166912 3.74319 0.410058 3.53628

12. Living Environment: Lab 16
1. We set up our experiment
2. We burned stuff
3. We measured stuff
4. We wrote down stuff
5. We compared stuff
6. Now we talk about stuff…