Thermal Energy and Temperature Lab
7th Grade PSI
Name _________________________
Grade
/ 20
Experiment Question:
How can the difference between thermal energy and temperature be experimentally
observed?
Hypothesis Starters:
1. What is temperature?
2. Do all substances have the same amount of thermal energy at the same
temperature? Explain your thinking.
3. What factors influence the amount of thermal energy an object has?
Purpose:
During this experiment, you will explore the difference between thermal energy
and temperature. Often people think of temperature as being a measure of how much
energy something has, but this is not the case. Temperature is related to energy but
takes additional factors into account. If there are two objects that have the same amount
of energy, they may have different temperatures if one has twice the mass of the other.
In that case, each molecule would only have half as much energy, so the temperature is
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Chemical Reactions and Energy
lower. Other factors also play a role as you have hopefully already discussed in your
hypothesis starters.
In this experiment, you will observe how temperature changes as water
transitions between its three phases: solid ice, liquid water, and water vapor. Pay close
attention to when the temperature rises and when it remains constant. Also, since you
will be adding energy to make the phase changes happen, be careful not to get burned.
Materials:
For each person:
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Safety goggles
Apron (optional)
For each group:
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One heat source (hot plate, Bunsen burner, or candle)
Matches or lighter (if using Bunsen burner or candle)
One thermometer (non-mercury for safety and a digital thermometer is preferred)
One test tube and test tube holder (if using the Bunsen burner or candle)
One small flask or beaker and a pair of tongs (if using the hot plate)
Crushed ice
Tap water
Balance or scale
Clock, stopwatch, or other timer
Safety:
You are dealing with heat sources and hot glassware. Use the test tube holder or tongs
to hold the hot glass. If you are using a flame, make sure long hair is pulled back and
avoid loose fitting clothing. Never point a container that is heating at someone. Make
sure it is pointed away in a safe direction in case something splashes out.
Procedure:
1. Gather all materials and read all directions before getting started.
2. Add crushed ice to the test tube, flask, or beaker.
If you are using a candle as your heat source use between 2.0 g and 3.0g of ice.
If you are using a Bunsen burner or a hot plate, use between 15.0g and 20.0g of
ice.
3. Place the thermometer so that it is down in the ice in your container.
4. Add enough tap water to cover the bulb of the thermometer or if you are using a
digital thermometer, add enough water so that about 1.5cm of the tip is under
water.
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Chemical Reactions and Energy
5. Once the temperature stabilizes, record the temperature of the ice/water mixture
and record this as the time 0.0 minutes temperature on the data table or in your
lab notebook.
6. Turn on your heat source and start heating the ice water mixture. (Set hot plates
to medium high power.)
7. Every 20 seconds until enough water has boiled away that the thermometer is
not able to give an accurate reading, make a measurement of the temperature
and record it in the data table.
REMINDER: Do not let your thermometer bulb touch the bottom or sides of the
glass while you are heating. The glass should be hotter than the water inside.
That is what causes the energy to flow.
8. When the ice has completely melted, put an “M” beside that time in the data
table.
9. When the liquid begins to boil put a “B” beside that time in the data table.
10. When you can no longer accurately measure the temperature, turn off your heat
source.
11. Clean up your laboratory station and return all materials to their proper locations.
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7th Grade PSI
Chemical Reactions and Energy
Graphing Results:
Using the results from your data table, draw a graph of temperature (vertical axis)
versus time (horizontal axis). Be sure to include units on your axis labels. Using a
different color than you used for the data points, connect the data points to form a
curved shape. Use the graph to help you answer the Laboratory Questions below.
Laboratory Questions:
On a sheet of paper or in your laboratory notebook, answer the following questions
about the experiment.
1. What happened to the temperature of the mixture as the ice melted?
2. What happened to the temperature of the liquid water after it was done melting
but before it started boiling?
3. What happened to the temperature of the water while it boiled?
4. Did your heat source ever stop giving energy to the water?
5. If all of the energy from the heat source was absorbed by the water, how do you
explain why the temperature did not change significantly during each of the
phase changes?
Conclusion:
On a sheet of paper or in your laboratory notebook, write one or two paragraphs that
summarize the experiment results and cover the following key points.
1. Explain in your own words how the experiment shows that temperature and
thermal energy are similar but not the same thing.
2. Explain what happened to temperature in each of the three time periods: Melting,
Heating, and Boiling.
3. Explain whether this is an endothermic or an exothermic process.
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Chemical Reactions and Energy
TEMPERATURE RESULTS DATA TABLE
Time
(seconds)
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
160.0
180.0
200.0
220.0
240.0
260.0
280.0
300.0
320.0
340.0
360.0
380.0
400.0
420.0
440.0
460.0
480.0
500.0
520.0
540.0
560.0
580.0
600.0
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Temperature
(degrees Celsius)
Time
(seconds)
Temperature
(degrees Celsius)
620.0
640.0
660.0
680.0
700.0
720.0
740.0
760.0
780.0
800.0
820.0
840.0
860.0
880.0
900.0
920.0
940.0
960.0
980.0
1000.0
1020.0
1040.0
1060.0
1080.0
1100.0
1120.0
1140.0
1160.0
1180.0
1200.0
7th Grade PSI
Chemical Reactions and Energy