PhysicsLAB

PSL Calorimetry Lab
#1 Water Mixtures

Enter each group member's AIDE letters

Enter your class period (1-8)

mass of empty styrofoam "cold" cup kg
mass of cup with cold water
be careful to fill the cup a little LESS than full
kg
mass of cold water kg
mass of empty styrofoam "hot" cup

kg
mass of cup with hot water
be careful to fill the cup a little LESS than full
kg
mass of hot water kg

At this time, you need to minimize (NOT close) your browser window. Next go to Start, Programs, Personal Science Laboratory and PSL Excelerator. When Excelerator opens, click on the thermometer icon. To calibrate a thermometer, enter the number taped to the probe's wire and choose extended. Answer okay to location to the right of $C:$C. Click on the experiment clock and set the duration to 10 minutes (not seconds). When you are ready to measure and record the water temperatures, press the G for GO button.

initial temperature of cold water C
initial temperature of hot water C
specific heat of water 4186 J / kg C

When you are ready to mix the two water sample together, carefully pour the COLD water into the HOT water. Note that no water should overflow from the HOT water cup since both cup samples were initially LESS than full. Use the temperature probe to gently stir the mixture - record the final equilibrium temperature. Do NOT slosh any water out of the HOT cup.

EXPERIMENTAL (MEASURED) final temperature
of water mixture

C

Calculations: Use the Law of Heat Exchange

Sheatgained + Sheatlost = 0

to solve for the theoretical final temperature of the water mixture. Be sure to first write your variable expression with m's, c's, Tf's and To's before you substitute in your experimental values to solve for Tf.

Conclusions: Determine the accuracy of your experiment by calculating your data's percent error.

% error = | Experimental - Theoretical | * 100
Theoretical

EXPERIMENTAL (MEASURED)
final temperature of water mixture
C
THEORETICAL (CALCULATED)
final temperature of water mixture
C
% error %

Discuss what your group feels is this lab's (a) greatest source of error and (b) a valid procedure that could minimize the error's negative consequences when the lab is completed next year.

When you are finished with the experiment, close PSL Excelerator (File, Exit - do NOT save changes or any data), dry off the probe, empty your water samples into the front sink and turn your empty cups upside down on a paper towel to dry out for next period.



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PhysicsLAB

Mainland High School
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