Boiling Point Lab
Hari- Modifications
8th grade science

Introduction/Thinking
Questions
• What is boiling?
• Is boiling always hot?
• What happens to a liquid when it boils?
• What is the boiling point of water (in Celsius)?
• What do you think will happen to the temperature of boiling water if you continue to heat it for 5 minutes?

I. Define the Problem:
We do not know what will happen to the temperature of solid water as we heat it to water vapor.

II. Focus Question:
What happens to the temperature of ice as we heat it to boiling and continue to boil it?

III. Prediction:
I think that the temperature will
_____. I think this because______.

IV. Share:
Most people think the temperature will go up, a few said it will stay the same.

V. Plan of Action
A. Materials:
Hot plate, beaker, ice, thermometer, salt, goggles, tongs

V. Plan of Action
B. Independent Variable: heat or energy, time

V. Plan of Action
C. Dependent Variable: temperature

V. Plan of Action
D. Control:
Amount of water/ice

V. Plan of Action
E. Procedure:
1. Put a few milliliters of water in your beaker. Fill it up with ice and stir gently with thermometer.

V. Plan of Action/ E. Procedure
Continued:
2. When the temperature has not changed for 2 minutes (stops falling) record the temperature.
You are ready to begin the lab.

V. Plan of Action/ E. Procedure
Continued:
3. Place the beaker on the cold hot plate.
Stir the ice continually with the thermometer and record the temperature every 30 seconds. Do not allow the thermometer to touch the bottom of the beaker. Continue heating until the water boils.

V. Plan of Action/ E. Procedure
Continued:
4. Once it boils, heat for an additional 5 min.

V. Plan of Action/ E. Procedure
Continued:
5. Record all information in a chart.

V. Plan of Action/ E. Procedure
Continued:
6. Repeat procedure the next day adding salt to the ice.

VI. Data Chart
A. Leave a blank page for data. Include labeled data charts
(i.e. plain water, water with salt, etc...).

VI. Data Continued
B. Data Graph
Leave the next page for the graph of the data.
Temperature on Y axis vs Time on X axis.

VII. Drawing:

VIII. New Vocabulary
• Boiling Point
• Phase Change
• Acclimation

IX. Claims and Evidence
Make at least 4 claims backed up by evidence from the data and graphs.
Example: I claim that _______. I claim this because ________.

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
1. What type of change did the water undergo when it changed from a solid to a liquid to a gas?

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
2. When water boils, bubbles form at the bottom and rise to the top.
What exactly are the bubbles comprised of and why do they appear to form at the bottom of the beaker?

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
3. Why didn ’ t the temperature of the ice water mixture increase rapidly once it was placed on the hot plate?

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
4. After about 3-5 minutes of heating the temperature began to rise very quickly, why did this occur?

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
5. Why didn ’ t the temperature continue to rise once it reached the boiling point?

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
6. How can water boil below 100o C?

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
7. Based on your results how does adding salt affect the freezing and boiling points of of water?

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
8. Calcium Chloride (salt) is used in the winter to melt ice on roads and sidewalks. When salt is added to ice it makes the temperature of the ice colder. How can ice melt if the temperature actually becomes colder?

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
9. At the boiling point the heat of vaporization occurs. Based on your observations, what do you think the heat of vaporization is?

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
10. Element z has a boiling point of 72o C at standard atmospheric conditions.
Yesterday, a lab group measured the boiling point of z to be 65o C. Why did this occur and what happened physically to to z when it reached this temperature?

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
11. Describe what is happening to the molecules of the water as it changes from a solid to a liquid to a gas.

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
12. List two characteristics of solids, liquids,and gases that apply only to those phases.

X. Conclusion and Reflection
Either copy questions or create a complete sentence answer out of the questions.
13. Draw how you think the molecules look and how they must be arranged when the water is a solid, a liquid, and a gas. Make sure you label each diagram.

X. Conclusion and Reflection
14. Discussion Summary: Write a paragraph describing the main ideas and concepts in this lab.
Include the overall purpose in doing the lab. (Do not restate the problem statement or the results)

XI. Hypothesis Reflection
My hypothesis was correct or incorrect because……..

XII.Questions for further thinking
Make at least 3 “ I wonder… ” or “ I am still thinking about… ” statements.