Phase Transitions

March 5th, 2013

Agenda

Warm-up/Vocab/Set-up Notebooks- 20 minDry Ice Demonstration & Questions- 30 minPhase Transitions Diagram – 10 minCondensation Experiment- 20 minStudent Designed Experiment- 20 min

Warm-up

Sometimes you can see water droplets on car windows in the morning, even if it didn't rain the night before! Where do these water droplets come from? (No, it's not the sprinklers)

Set up your interactive notebooks!

On the next blank page, set up Cornell notes.

Topic: Phase Transitions

Focus Question: 1) What are the 6 different phase transitions and what causes the changes?

Vocabulary Cards

Property: A quality or characteristic of something

Ex:- A property of metals is that they all conduct heat very well- One property of water is that its molecules are highly attracted to each other- Green tea is famous for its healing properties

Dry Ice Demonstration

Observe the demonstration given and follow along with the questions on your worksheet.

Copy all notes in YELLOW

The 6 phase transitions are: freezing and melting (solids and liquids)evaporation and condensation (liquids and gases)sublimation and deposition (solids and gases)

sublimation is the direct change from solid to a gasdeposition is the direct change from gas to a solid

Experiment

Observe the cup at your table. What do you notice has formed on the sides of the cup?

Hypothesis

Create a hypothesis: where do you think these water beads came from?

Experiment

Try to design an experiment that would test to see whether your hypothesis is correct or not. Discuss

with your elbow partner.

Class Hypothesis

There are many possible hypotheses, but we will use just one today. The water beads are formed by water vapor (gas) around the cup condensing into liquid.

Procedure

We'll read the procedure together as a class.

Write down your prediction

Copy down this diagram as we wait

Back to the experiment

What did you notice? Complete your worksheet with your group. -10 minutes

Take it a step further...

Think about this: What exactly causes the water vapor to condense? We know that water vapor comes from the air... but why does it change from water vapor (gas) to beads of water (liquid)?

Hint: What do we know about freezing and boiling points?

What causes ice to melt and water to boil?

TemperatureDesign an experiment to test whether decreasing the

temperature of the air (where the water vapor is) will affect condensation.

Your materials: - 4 cups - ice - warm water - magnifying glass

Hint: setting up your cups like this is best to see condensation.

Question: Does decreasing the temperature of the air increase condensation?

You will have 20 minutes to design and conduct an experiment. You will be graded on participation

points out of /10.

At the end of 20 minutes, be prepared to present your findings on whether decreasing the temperature of the air affects condensation. Give your conclusion

and supporting observations.

We learned in our last unit that increasing the temperature increases the speed of molecules until they break apart from their attractions.

Similar,y when we decrease the temperature, molecules will slow down and become re-attracted to other molecules! This is how gas becomes liquid and liquid becomes gas.

(Show animation).

Answer Focus Question 1

What is the phase transition of a liquid turning into a solid called?

A liquid turning into a gas?Gas turning into solid?

What causes phase transitions?