1. Water Phase Change Graph
Heat plays an important role in phase changes. Heat is energy that causes particles of matter to move faster and farther apart. As particles move faster, they leave one phase and enter another. Phase changes produce changes in only the physical properties of matter. They do not produce changes in the chemical properties. A substance is still the same kind of matter regardless of its phase.

2. Solid A solid has a definite shape and volume
The particles are packed tightly together and the only motion is vibration.

3. Liquid
A liquid has a definite volume, but takes the shape of its container
The particles are also tightly packed, almost as close as a solid, but the particles are free to move

4. Gas A gas has no definite shape and no definite volume.
The high energy particles move freely
click here to see animations of a solid, liquid and gas

5. animations Solids, liquids and gases in containers
Molecular level phases

6. Water Phase Change GraphD
100
gas C
Temperature º C.
liquid B
Pass out the Water Phase Change Graph blank to all students.
As we work through the phase changes, please add to your graph.
This is a graph that shows the energy and temperature changes as water turns from a solid, ice, to a liquid, water, and finally to a gas, water vapor. As we make additions on the board, you will make the additions to your paper.
Mark the letters A, B, C, D and E.
(click) First, we show that the molecules of water in the solid form are tightly packed and in a regular pattern forming crystals. We’ll take a closer look at the actual pattern later. Draw the crystal lattice here showing that water is a solid below zero degrees Celcius.
(click) Next we show water molecules in the liquid state here between zero and 100 degrees Celcius. Draw the molecules a bit farther apart and without a crystal structure.
(click) And here we have water in the gas state with the molecules farther apart A
solid
Heat (thermal energy)

7. Heat (thermal energy) E D 100 gas C liquid B A solid Temperature º C.
As water changes from solid to liquid to gas, what is happening to the energy of the molecules?
(increasing) (click)
What is happening to the temperature?
(increasing) A
solid
Heat (thermal energy)

8. Heat (thermal energy) condensing boiling freezing melting E D 100 C B
Temperature º C. B
freezing
When the ice reaches zero degrees what starts happening?
(melting from solid ice to liquid water) (click)
If we were moving in the opposite direction, with decreasing energy and temperature, from liquid water to solid ice, what would that be called?
(Freezing) (click)
As the liquid water reaches 100 degrees, what happens?
(change from liquid to gas, boiling) (click)
If we were moving in the opposite direction, with decreasing energy and temperature, from water vapor to liquid water, what would that be called?
(condensation, condensing) (click)
Answer the questions of the bottom of your paper.
melting A
Heat (thermal energy)

9. http://mutuslab. cs. uwindsor
Let’s take a look at what the molecules look like in a solid, liquid and a gas

10. And an animation of the phase changes of water