Calorimetry

Martin, Daniel          Chicago H.S. for Agricultural Sciences 
                        1-312-881-5000
                           

Objectives

1. To learn basic principles of calorimetry.
2. To recognize the large amount of energy stored in food.
3. To learn to solve problems associated with calorimetry.

Equipment and Materials

2 Aluminum pop cans
3 small wood or sheet metal screws
1 paper clip
1 peanut half
1 thumb tack

Recommended Strategy

Construct a simple calorimeter by punching three holes in the bottom rim of a pop can 
equal distances apart and inserting the screws. Now put a hole in the bottom of the 
same can by sectioning the aluminum and bending it inward. Next drill a hole through 
the bottom rim large enough to allow a paper clip to be passed through. Finally, cut 
a rectangular port hole in the can about one inch from the bottom rim. The other pop 
can should fit snugly on top of the inverted burner pop can at this point. Now 
measure out a known amount of water and pour it into the whole pop can and record its 
temperature. Next mass and puncture a peanut half (dry roasted won't work as well) 
with a thumb tack. With the hole started, impale the peanut on a stretched out paper 
clip. Remove the peanut, hold it in the center of the top of the burner can and 
insert the paper clip through the hole in the can and the peanut, resting the end of 
the clip on the rim of the can. Place the can with the water on top of the burner can 
and ignite the peanut with a wooden match using the port hole for access. Let the 
peanut burn out completely and immediately record the temperature of the water. You 
can now make various calculations and determine the calories released by the peanut, 
calories per gram of peanut and even a percent error using a known value for peanuts 
which can be found in a calorie counting table. 

Heat     = mass of H2O X change in temp of H2O X specific
given off                                       heat of H2O
by peanut

The short form of the equation is Q = m*dT*Cp