1. The Four Phases Phase Changes Boyle’s Law & Charles’s Law
Chapter 3
The Four Phases
Phase Changes
Boyle’s Law & Charles’s Law

2. Matter exists in four phases:
SOLID
LIQUID
GAS
PLASMA

3. Phases of Matter

4. SOLIDS Have a definite shape Have a definite volume
Particles packed very closely together – they are sometimes arranged in a regular repeating pattern called a CRYSTAL
Particles may only vibrate – too close to move
Some particles are NOT arranged in a pattern – called AMORPHOUS solids – and may lose their shape over time under certain conditions
Examples include: window glass, candle wax, tar, silicone rubber

5. LIQUIDS
Have no definite shape – particles are free to move or flow because they are not as closely packed
Have a definite volume – but must take the shape of its container
Some liquids flow more freely than others
VISCOSITY is a liquid’s resistance to flow
Which is more viscous – HONEY or WATER?
Oil & other lubricants have high viscosity

6. GASES No definite shape No definite volume
Particles are free to move so they fill the available space, regardless of the size or shape of the container
What holds Earth’s atmospheric gases so they don’t expand into deep space?
Particles are in constant motion – moving so fast that they’re colliding with each other & the container at great speeds

7. PLASMA Rarely found on Earth
Very common in the universe (stars, like our sun)
Matter is extremely high in energy
Very dangerous to living things

8. BEHAVIOR of GASES
Because the particles of a gas are in constant motion, changing the temperature of or the pressure on the particles will have an effect on the behavior of the particles in the space (volume) they occupy
Two laws help us understand the relationship

9. Boyle’s Law P2 V1 With a fixed amount of gas:
when the pressure increases, the volume decreases
when the pressure decreases, the volume increases
This is an inverse proportion
P1 = V2
P V1

10. Charles’s Law T2 V2 With a fixed amount of gas:
when the temperature increases, the volume increases
when the temperature decreases, the volume decreases
This is a direct proportion
T1 = V1
T V2

11. Which law is being shown in this cartoon?

12. PHASE CHANGES
Substances will change from one phase to another by adding (absorbing) or taking away (releasing) ENERGY
Adding energy causes the particles in a substance to move faster & spread out
Releasing energy causes the particles in a substance to slow down & come together
Example = water vapor, liquid water, & ice

13. Phases changes are beneficial:
This is why freezing water can “save” fruit by the release of energy which the fruit takes on
This is also why evaporation of water or sweat from the skin is a cooling process

14. Phases changes include:
MELTING – change from a solid to a liquid
FREEZING – change from a liquid to a solid
VAPORIZATION – change from a liquid to a gas (like evaporation)
CONDENSATION – change from a gas to a liquid

15. Phase Changes

16. Sublimation Examples include: dry ice, fallen snow, air freshener
Some substances are able to change from a solid state directly to a gaseous state without ever becoming a liquid
Examples include:
dry ice, fallen snow, air freshener

17. Melting Point vs. Freezing Point
The temperature at which a solid changes to a liquid
The temperature at which a liquid changes to a solid
They’re equal to each other, meaning water will melt & freeze at 0°C

18. What is happening at X? What is the temperature?

19. Evaporation vs. Boiling
Evaporation occurs when a phase change (liquid to gas) occurs from the surface of the liquid
Boiling causes the phase change to occur within the liquid & gas bubbles rise to the top

20. Condensation vs. Boiling Point
The temperature at which a gas changes to a liquid
The temperature at which a liquid changes to a gas
They’re equal to each other, meaning water will condense & boil at 100°C

21. Phase Change Graph for Water