Surabaya Cambridge School
Science Department
Date Performed:
Date Submitted:
Class & Section:
CHEMISTRY 9
LABORATORY ACTIVITY
1st Term, AY 2026 - 2027
Group Members:
Rating:
HEATING AND COOLING CURVE OF WATER
Laboratory Activity No. 1
Aim: Draw the heating and cooling curve for water.
Apparatus:
Two 250 ml heat resistant beakers
Ice cubes
Wash bottle with water
One alcohol lamp
One tripod
Two thermometer
Stop watch
Sodium chloride
Warning:
Be careful when handling the beaker of hot water. Do not touch the beaker with your hands, you
will burn yourself.
Method:
Experiment 1:
1. Place some ice in one of the beakers.
2. Stir the content well and take the temperature reading on a thermometer. Start the stop watch at the
same time and take a temperature reading every minute, for at least 10 minutes, while stirring continually
Experiment 2:
1. Set up the tripod stand with gauze over an alcohol lamp.
2. Fill the other beaker with 50 ml of water.
3. Ignite the alcohol lamp.
4. When the water starts boiling, remove it from the heat and take the temperature reading on a
thermometer.
5. Extinguish the alcohol lamp. Start the stop watch at the same time and take a temperature reading
every minute, for at least 10 minutes, while stirring continually.
Experiment 3: (Repeat Experiment 1 but add 5 grams of sodium chloride to your ice)
1. Place the ice in a 50 mL beaker.
2. Add 5 grams of sodium chloride into the beaker with the ice.
3. Stir the content well and take the temperature reading on a thermometer. Start the stop watch at the
same time and take a temperature reading every minute, for at least 10 minutes, while stirring
continually.
4. Record your reading on the table provided.
Experiment 4: (Repeat Experiment 2 but add sodium chloride to the water in the beaker)
1. Set up the tripod stand with gauze over a an alcohol lamp.
2. Fill the other beaker with 50 ml of water.
3. Ignite the alcohol lamp.
4. When the water starts boiling, remove it from the heat and take the temperature reading on a
thermometer.
5. Add 5 grams of sodium to the beaker.
6. Extinguish the alcohol lamp. Start the stop watch at the same time and take a temperature reading every
minute, for at least 10 minutes, while stirring continually.
Results
Record your results in the following table:
Experiment 1
Time (min)
Temperature (in oC)
Experiment 2
Time (min)
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
10
9
10
Temperature (in oC)
Experiment 3
Time (min)
Temperature (in oC)
Experiment 4
Time (min)
0
0
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
10
9
10
Temperature (in oC)
Analysis of the result:
With the result recorded in the table four graphs of temperate vs. time. Two for the heating curve of
water and the other two for the cooling curve of water.
Post-lab Questions:
1. What are the phase changes that occurred during the heating and cooling of water? Identify the
temperature ranges where these changes happened.
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2. Why does the temperature remain constant during melting and boiling, even though heat is continuously
added?
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3. Describe what is happening at the particle level during the melting and boiling points for Experiment 1
and 2.
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4. What type of energy is being absorbed during the phase changes, and what is it used for?
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5. What effect would adding salt (or another impurity) to the water or ice have on the heating or cooling
curve? Explain why this happens in terms of freezing point or boiling point changes.
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6. What is happening to the particles during condensation?
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7. Explain why the temperature does not decrease during the phase changes even though the system is
losing energy.
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8. Based on your heating and cooling curve of water, describe the changes that occurred in terms of
temperature, state of matter, and energy. What conclusions can you draw about how energy affects the
state and temperature of a substance?
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Graph 1 (Experiment 1)
Graph 2 (Experiment 2)
Graph 3 (Experiment 3)
Graph 4 (Experiment 4)