Name:
Date: 10/15/13
Period:
Explore: Stearic Acid Lab
Objectives:
 Students will determine how temperature plateaus as a substance freezes
 Students will incorporate understanding of the kinetic theory of matter to
identify and explain the behavior of solids, liquids, gases
 Be able to explain how a solid forms and how it melts (particles/energy)
Purpose/Problem: How does a substance behave as it freezes?
Hypothesis :
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Materials/ Methods- List all materials used in lab/ activity.
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Student Materials
Safety goggles
Test tube rack
Thermometer
Test tube with molten stearic acid
Lab report worksheets/ data sheet
Pen pencil
Instructor Materials
*Safety goggles
*Hot plate
*Glass beakers
Procedures- Step by step instructions – Label each step 1, 2, 3, etc…
1. Get into pre assigned groups/ pairs, sit at lab station (desks)
2. Take out lab report worksheets/ data sheet and writing utensil
3. Collectively
*Determine activity/ lab purpose
*Address and discuss research
*State hypothesis
1. Put on Safety goggles
2. Teacher will distribute molten stearic acid test tubes and place them in test
tube rack
3. Record starting temperature, appearance and state of matter
4. Record and repeat step 6 every 30 seconds for between 10 and 15 minutes
5. Clean up lab stations(desks)
*Return thermometers, test tubes, and goggles to instructor station
*Wipe/ clean any dirty lab area
9. Work on/ complete Lab report questions
* Create graph for temperature data
4. Experiment: Observations
Freezing Liquid Lab/ Activity Data Sheet (10-15minutes)
Elapsed time
(sec)
Start 0:00
0:30
1:00
1:30
2:00
2:30
3:00
3:30
4:00
4:30
5:00
5:30
6:00
6:30
7:00
7:30
8:00
8:30
9:00
9:30
10:00
10:30
11:00
Temperature
*C
Appearance /Observation
Physical State
11:30
12:00
12:30
13:00
13:30
14:00
14:30
15:00
Analysis: Create a line graph of your data
Discussion: Answer the questions to help you describe what happened in your
experiment
1. Describe what happened to the stearic acid as it cooled down (ie: how did
you know it was starting to freeze?
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2. Was your hypothesis supported? Why or why not?
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3. What state of matter is stearic acid at room temperature? _______________
4. What do you think the freezing point of stearic acid is? _________________
5. Describe what you think is happening to the molecules of stearic acid as it
was freezing?
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6. In the test tubes below to draw the particle arrangement of the stearic acid.
LIQUID/MOLTEN
SOLID
7. Based on your observations what type of solid did the stearic acid become, a
crystalline solid or non- crystalline solid? Explain your answer
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8. How does the stearic acid behave differently than water when it freezes?
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9. In one sentence describe what you learned in this experiment.
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