Heating Curves 1
Name ______________________________________________ Date _________ Period ______
Heating Curves Lab
Pre-Lab Discussion (Do Not Write in Lab Report)
When heat is added to ice, it will melt and change to water. As water is heated, its temperature
rises. Eventually, the water will boil and change into a vapor (gas). The substance has gone
through two changes in phase. The temperatures at which these phase changes occur are
important characteristic properties. The relationship between the heat energy and the behavior of
the substance is also important in understanding the difference between heat and temperature. In
this lab experiment you will be dealing with the relationship between heat energy and changes in
phase of matter.
Purpose
To create a heating curve for water from solid ice to water vapor.
Equipment / Materials
250mL Beaker
Ring Stand
Iron Ring
Wire Gauze
Bunsen Burner
Vernier Temperature Probe
Ice
Liquid Water
Test Tube Clamp
Stirring Rod
Procedure
1. Fill a 250 mL beaker 2/3 full with ice and add water to cover the ice.
2. Place the beaker on a wire gauze on a ring stand. Clamp a Vernier probe so that it is
below the water line. Do not let the sensor rest on the bottom or side of the beaker.
3. Stir carefully with a stirring rod until the temperature stabilizes at or below 0.0°C. Record
the temperature at 30-second intervals.
4. After two minutes (record the time below the table), warm the ice water over a Bunsen
Burner and continue to record the temperature at 30-second intervals. NOTE: Once the
Bunsen Burner is set, leave it at this setting and make no adjustments to the flame. Stir
continuously while heating.
5. Record the time at which all the ice has melted. Also record the time at which the water
begins to boil.
6. Continue to heat the water for at least 3 minutes after the water begins to boil, recording
the temperature at 30-second intervals. After three minutes, turn off the burner and record
the time.
7. Plot a heating curve using your data. On the curve, indicate the point at which the ice
melted and the liquid water boiled.
Heating Curves 2
Data
Time Elapsed
(minutes : seconds)
Beaker
Temperature (°C)
Time Elapsed
(minutes : seconds)
0:00
13:00
0:30
13:30
1:00
14:00
1:30
14:30
2:00
15:00
2:30
15:30
3:00
16:00
3:30
16:30
4:00
17:00
4:30
17:30
5:00
18:00
5:30
18:30
6:00
19:00
6:30
19:30
7:00
20:00
7:30
20:30
8:00
21:00
8:30
21:30
9:00
22:00
9:30
22:30
10:00
23:00
10:30
23:30
11:00
24:00
11:30
24:30
12:00
25:00
12:30
25:30
Beaker
Temperature (°C)
Heating Start Time______________
Ice Melting Time________________
Heating End Time_______________
Water Boiling Time_____________
Heating Curves 3
Questions
1. What was happening to the water when the lines on the graph were mostly flat? What
kind of energy was being added to the system?
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2. What was happening to the water when the lines on the graph were mostly sloped? What
kind of energy was being added to the system?
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3. Was the energy flow into the beaker constant? How did you know? Can you make a
useful heating curve if the energy flow is not constant? Why or why not?
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Conclusion
Based on your heating curve, determine the melting and boiling points of water. Does this match
the accepted values (0°C for melting and 100°C for boiling)? What sources of error (3+) are
there in the experiment that may keep you from having the perfect melting and boiling points?
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Heating Curves 4