1. Lesson 7
Just a Phase

2. Lesson 7 – Just A Phase
As ice is heated, you will observe the phase changes that occur. You will also observe melting and boiling points. 2

3. Lesson 7 – COS
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4. Objectives Discuss your current knowledge of phase change.
Observe what happens to ice as it is heated.
Measure the temperature of ice water as it is heated.
Plot a graph of your measurements.
Interpret your graph and other observations.

5. Getting Started Answer the following questions:
How could you make spaghetti cook faster?
Why does ice melt?
Why can you play in the snow when its warm outside?
Why doesn’t ice melt immediately when you add it to a soft drink?
Are things that are boiling always hot? Are things that are frozen always cold?
What are some of you own questions about what happens when ice melts and water boils?

6. Vocabulary
Phase or state – solids, liquids and gases are the three main states of matter. Two other states include plasma’s and Bose Einstein condensate’s
solid: A phase or state of matter in which a substance has a definite shape and volume
Liquid: A phase or state of matter in which a substance has a definite volume but no definite shape. Liquids take the shape of their container.
Gas: A state or phase of matter in which a substance has no definite shape of volume.

7. Lesson 7 – (1-1) Vocabulary
melting - the phase change in which a solid turns into a liquid.
melting point - the temperature at which a solid turns into a liquid; the same temperature as the freezing point
boiling - the process by which a liquid changes into a gas at its boiling point. .
boiling point - the temperature at which a liquid changes into a gas; boiling point depends on air pressure.…… 7

8. Vocabulary
Freezing: The change in state in which a liquid turns into a solid
freezing point – The temperature at which a liquid turns into a solid (altered by changes in pressure)
Vaporization/ evaporation – The change of a substance from a liquid to a gas.
Condensation – The change of state from a gas to a liquid
Phase change - change from one state to another

9. Lesson 7 –
Question
How does heat affect phase changes? 9

10. Lesson 7
Hypothesis 10

11. SAFETY Tie back long hair Wear safety goggles throughout the inquiry
Be careful when you handle hot apparatus

12. Lesson 7 Procedure Gather materials. Construct a data table.
Pour 1 cm. of water into a beaker. Add ice.
Measure and record temp. of ice water.
Place beaker on stand over alcohol burner.
Record temp. every 30 seconds.
When water boils, continue to record temp. for 3 more minutes (30 second intervals).
Graph the data. 12

13. Temperature of water (C degrees)
Results
L Temperature v. time
Time
(min. and s)
Temperature of water (C degrees)
Observations
30 s
1 min
1 min, 30 sec
2 min
2 min, 30 sec
3 min
3 min, 30 sec
4 min
4 min, 30 sec 13

14. Lesson 7 – (1-2) Conclusion
Phase changes are dependent on temperature and pressure.
Three phases or states of matter: solid, liquid, gas
Phase changes take place when molecules lose or gain kinetic energy (heat energy) and can be related to a change in temperature.
Lose kinetic energy – molecules move
closer – (gas > liquid > solid).
Gain kinetic energy – molecules move
apart – (solid > liquid > gas)
A change of state is not the result of a chemical reaction. 14

15. Lesson 7 - (2-2) Conclusion
The melting point and boiling point of a substance is a characteristic property of the substance.
Freezing and melting points are the same.
An increased input of heat has no effect on the boiling point of a substance, although it will make a fixed mass of matter change state faster.
Substances that boil are not always hot. Many substances melt and boil below 0 degrees C…... 15