Phases and Their Changes
Essential Question:
What are the properties of the states
of matter and how do they change?
Melting vs Freezing points?
Evaporation vs. Condensation points?
Sublimation vs. Deposition points?
List the 4 phases of matter
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1.Solid
2.Liquid
3.Gas
4.Plasma
Use a diagram to describe
the three most common
phases of matter
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Phase Change Diagram
Phases of matter are
PHYSICAL PROPERTIES.
What is necessary to cause a
change in phase in the three
most common phases?
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Energy. An increase in energy will cause
a solid to change to a liquid and a liquid
to change to a gas.
There is no such thing as adding or
removing cold.
Describe SOLID
This screen will
disappear in 3
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minutes.
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The solid phase of matter
occurs when the
material has a definite
volume or size and
distinct shape at a
given temperature.
Describe LIQUID
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A liquid has a
definite volume, but
it takes the shape
of its container with
the aid of gravity.
Describe GAS
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The volume of a gas
depends on its
temperature and the
surrounding pressure. It
will take the shape of its
container if the
container is closed.
Therefore
Definite Volume Definite Shape
• Solid
Yes
Yes
• Liquid
Yes
No
• Gas
No
No
But what happens if you raise the
temperature to super-high levels…
between
1000°C and 1,000,000,000°C ?
Will everything
just be a gas?
STATES OF MATTER
PLASMA
 A plasma is an
ionized gas.
 A plasma is a very
good conductor of
electricity and is
affected by
magnetic fields.
 Plasmas, like gases • Plasma is the
have an indefinite
common state
shape and an
of matter
indefinite volume.
STATES OF MATTER
SOLID
Tightly packed, in
a regular pattern
Vibrate, but do not
move from place
to place
LIQUID
Close together
with no regular
arrangement.
Vibrate, move
about, and slide
past each other
GAS
Well separated
with no regular
arrangement.
Vibrate and move
freely at high
speeds
PLASMA
Has no definite
volume or shape
and is composed
of electrical
charged particles
Some places where plasmas are found…
1. Flames
2. Lightning
The Sun is an example of a star in its
plasma state
3. Aurora (Northern Lights)
COLD PLASMA ???
• In contrast, non-thermal or
cold plasma has only a
small fraction of its atoms
ionized. Examples of cold
plasma include fluorescent
lamps and neon signs.
Neon Lights could more
accurately be called "plasma
lights", as the light comes from the
plasma inside of them.
Triple Point Phase Change
Diagram
Phases
 Phases is the term scientist use to more
properly define solid, liquids and gases. It
means the same as the term “state”
 Phase is defined as “a part of matter that
has uniform properties through out the
entire substance”
Phases change
 As scientists we can change phases.
We can change a solid into a liquid and
a liquid into a gas.
 When two phases exist at the same
time it is called equilibrium.
 Equilibrium is a dynamic condition in
which two opposing changes occur in
equal rates in a closed system
Equilibrium
 To have equilibrium we need to have both
a temperature and pressure.
 When we have both a measured
temperature and pressure two or three
states will exist at the same time.
 Ice melting into water, water freezing into
ice.
Phase Diagrams
 Scientist have phase diagrams to show
exactly the temperature and pressure
must be achieved to have a solid, liquid,
gas, two phases or all three phases
 A phase diagram by definition is “a
relationship between physical states
that deals with temperature and
pressure.”
Phase diagram of
water.
Pressure is in
atmopheres (normal
pressure is 1 atm)
Temperature is in
celcius (water boils at
100)
Each of the lines represent equilibrium (two
states exist at the same time)
Point C is called the critical point
Critical point: is the point on which liquids and
gases are indistinguishable (can’t tell the
difference
Point A is called the Triple Point
The Triple point is the temperature and
pressure in which gas, liquid and solid all exist
in equilibrium
Video
• Sublimation
• Freezing
• Freezing Waves
Vapor Pressure
• The molecules in a liquid are constantly
moving and running into each other.
• Sometimes they will “bounce” out of the
container they are in.
• As a result, a faint vapor will exist over
most liquids.
Vapor Pressure
• Vapor Pressure is the pressure of vapor
over a liquid at equilibrium with the
atmosphere.
• When water boils the vapor pressure
exceeds the atmospheric pressure and the
molecules leave the liquid with little
impediment.
Vapor Pressure
• So then how do puddles evaporate and
why can clothes dry outside when the
temperature is below freezing???
• Water molecules are always moving and
are always escaping from their container.
Heat makes them move faster or slower.
Research
1. Pick out three different elements or
substances. A Solid, A Liquid and A Gas.
2. Not water. Tap Water is O.K.
3. Find their melting, freezing point,
condensation, evaporation point, and
sublimation, deposition point. In Celsius.
4. Select a synonym for each of the six
phase changes in #3.
5. Give an example of each.