2. Phase Changes  Objectives:  SWBAT describe phase changes of water  Catalyst:  Describe the law of conservation of matter in your own words.  Kevin thinks that drinking orange juice will allow him to stay up longer. Identify the independent variable, dependent variable, and control group.

3. Agenda  Catalyst  Phase Changes  Phase Change LAB!  Exit Question

4. Law of Conservation of Matter Lab  Make sure I check off your procedure before you start.  You have 30 minutes!

5. Remember the Kinetic Molecular Theory!  In the 3 different states, temperature is directly related to particle movement Temperature

6. 3 common states of matter  Solid- molecules are tightly arranged  Liquid- molecules flow over each other  Gas- molecules are further apart and move fast

7. Phase Changes  Key Point #1: When you change the amount of heat energy in a substance it will change from one state to another.

8. Ok, so how does it work?  So say I have my beaker of ice and I add some heat?  What is going to happen to the temperature?  Of course, the temperature goes up…

9. Temperature vs Heat Graph (During Phase Change) Temperature (˚C) Heating Time (min) Solid If you ADD Heat

10. DUH MR. J WHY ARE WE DOING THIS?  So it will just keep going up right?  NO! It is about to change phase and something very interesting happens…

11. Temperature vs Heat Graph (During Phase Change) Temperature (˚C) Heating Time (min) Solid If you ADD Heat You are still adding the same heat, but the temperature doesn’t increase when… IT IS CHANGING PHASE!

12. What is happening on a particle level during a phase change? Key Point #2: The energy added to a substance is NOT used to raise the temperature but instead to pull the particles apart from each other  It is a transition time!

13. What will happen if we keep adding heat?

14. Temperature vs Heat Graph (During Phase Change) Temperature (˚C) Heating Time (min) Solid Liquid If you ADD Heat Phase Change!!

15. What will happen if we keep adding heat?

16. Temperature vs Heat Graph (During Phase Change) Temperature (˚C) Heating Time (min) Solid Liquid If you ADD Heat Phase Change!!

17. What will happen if we keep adding heat?

18. Temperature vs Heat Graph (During Phase Change) Temperature (˚C) Heating Time (min) Solid Liquid Gas If you ADD Heat Phase Change!!

19. WHO’S PAYING ATTENTION?  What happens as you heat up a solid?  What happens during a phase change?

20. We have a name for the two phase change points  What do you think it is called when a solid moves to a liquid?  MELTING POINT!!  What do you think it is called when a liquid turns into a gas?  BOILING POINT!! (OR VAPORIZATION POINT!!)

21. Temperature vs Heat Graph (During Phase Change) Temperature (˚C) Heating Time (min) Solid Liquid Gas If you ADD Heat Phase Change!! Melting Point! Boiling Point!

22. What if you take away heat?  SAME THING JUST GOING DOWN!  YOU WANT A GRAPH?!?!  YOU GOT IT!

23. Temperature vs Heat Graph (During Phase Change) Temperature (˚C) Heating Time (min) Solid Liquid Gas If you ADD Heat If you REMOVE Heat

24. We have a name for the two more phase change points  What do you think it is called when a gas cools to a liquid?  CONDENSATION POINT!!  What do you think it is called when a liquid turns into a solid?  FREEZING POINT!!

25. Some vocabulary  Key Point #3: You must know the four points to look out for on a phase change graph.  Heating Up:  Solid  Liquid = Melting Point  Liquid  Gas = Boiling Point  Cooling Down:  Gas  Liquid = Condensation Point  Liquid  Solid = Freezing Point

26. Temperature vs Heat Graph (During Phase Change) Temperature (˚C) Heating Time (J) Solid Liquid Gas Freezes Condenses Melts Boils Melting Point Boiling Point If you ADD Heat If you REMOVE Heat Condensation Point Freezing Point

27. Time to do it yourself!!  Phase change lab time.

28. Exit Question  Draw the temperature vs. time graph for water that is being heated.  Explain why it makes this shape.