Chapter 4
States of Matter
Key Vocabulary
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Matter
Solid
Liquid
Viscosity
Gas
Surface tension
Thermal energy
Temperature
heat
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Melting
Freezing
Vaporization
Condensation
Pressure
Buoyant force
Archimedes’ Principle
Density
Pascal’s principle
Foldable
Pyramid Fold
 Side 1
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Side 2
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Solid
Liquid
Side 3
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Gas
What is matter?
Anything that has mass and takes up
space
 Give me some examples of matter
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States of Matter
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3 common states
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Solid, Liquid, Gas
1 rare state
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Plasma- found in stars, lightning, and neon
lights
 Common
in the universe, but uncommon on earth
Solids
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Matter with a definite shape and volume
Particles are moving in vibration patterns that
are not seen by the naked eye
Amorphous Solids
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Have no definite crystal structure
Examples: rubber, plastic, glass
Crystalline Solids
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Particles arranged in repeated 3-D structures called
crystals
Examples: Sodium Chloride (cube), diamond
(pyramidal)
Other examples: Sugars, sand, snow
Connection
Amorphous solids are like lemons in a
bowl
 Crystalline solids are like eggs in a carton
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What is a Liquid?
Has a definite volume, but no definite
shape
 Takes the shape of any container it is
poured into
 Particles move freely and allow shape
changes
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Viscosity
A liquid’s resistance to flow
 High viscosity means that the liquid is very
thick and does not run well
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Example: molasses
Low viscosity means that the liquid pours
easily
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Example: water
Gases
Matter that does not have a definite shape
or volume
 Particles are farther apart than in any
other common state
 Can be expanded or compressed
 Decreasing the volume (compressing)
moves the molecules closer together
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What is energy?
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The ability to do work or make a change
We will focus on the ability to make a change
now
 Ability to do work comes after the holidays
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The energy associated with motion is
called kinetic energy
 The chance that an object might exert
energy is potential energy
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Thermal Energy
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The total potential
and kinetic energy
Depends on the
amount of energy in a
substance as well as
how much of a
substance is present
Temperature
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The average kinetic
energy of a substance
What is the difference
between temperature
and thermal energy?
Heat
The movement of thermal energy from an
object with more kinetic energy to an
object with less kinetic energy
 When a substance gains heat, it gets
warmer
 When a substance is cooled, it looses heat
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What happens to the particles when they are
cooled?
Specific Heat
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The amount of energy
required to raise the
temperature of 1g of a
substance by 1
degree Celsius
Surface Tension
The uneven forces acting on the surface of
a liquid
 Cause the liquid to act as though there is a
thin film across the surface
 This unseen force allows bugs to float on
the surface of a liquid
 Believe it or not, you can actually float a
needle on water due to surface tension
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Surface Tension Lab
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Question: Can you place more drops of water on
the surface of a penny than what will simply fit
on the face of the penny?
Hypothesis: If…Then…Because
1 drop at a time place water onto the surface of
a penny
When the surface tension breaks, record the
number of drops in the data section of your
science journal
Repeat 3 times for accuracy
State Changes
Get out your pyramid foldable
 We are going to complete the sides of the
pyramid in the next few minutes
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Melting
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When an object absorbs
thermal energy
The increase in thermal
energy causes the
substance to change from
solid to liquid
Amorphous solids do not
change like other solids
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They simply get softer and
moldable
See figure 10 on page 109
Freezing
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When a substance
looses thermal energy
The substance
changes from liquid to
solid
The temperature at
which a substance
freezes is known as
freezing point
Vaporization
When a liquid gains thermal energy
 Changes from a liquid to a gas
 Example: Water boiling into vapor
 2 types of vaporization
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Boiling- air bubbles form within the liquid and
rise to the surface
 Evaporation- water at the surface vaporizes,
occurs at temperatures below the boiling point
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Vaporization Demo
I will place one drop of rubbing alcohol on
the back of your hand
 In your science journal, record your
observations for the next 2 minutes
 What happened?
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Condensation
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Decrease in thermal
energy rearranges the
pattern of a gas
Causes the gas to
turn into liquid
Sublimation
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Change from solid form to
a gas state without ever
becoming a liquid
Example:
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At room temperature
carbon dioxide is a gas
Dry Ice is the solid form of
carbon dioxide
At room temperature, dry
ice instantly turns into a
gas
Pressure
Equal to the force exerted on an object
divided by the area over which the force is
exerted
 Measured in SI Unit:
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Force is measured in Newtons (N)
 Area is measured in square meters (m2)
 Therefore pressure is N/m2 or a unit called the
Pascal (Pa)
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Atmospheric Pressure
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The air around you presses on your with a great
force, you are just used to the pressure so you
don’t feel it
Atmospheric Pressure on earth is 101.3Pa at
sea level
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This is equal to 101,000 N
Air pressure enables you to drink from a straw
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Sucking on the straw eliminates the air in the straw
The air pressure then pushes the liquid up the straw
where there is no longer air pressure pushing
downward
Using a Straw
Why don’t you feel the pressure?
The atmosphere pushes with equal force
on the outside of your body as the liquid in
your body pushes outward
 As altitude increases, air pressure
decreases
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When you rise in an airplane or go up a
mountain your ears pop. Why?
Buoyant Force
An upward force that presses against an
object being pushed downward by air
pressure and weight
 If the buoyant force is equal to the
combined forces, the object will float
 Archimedes’ Principle- the buoyant force
of an object is equal to the weight of the
fluid displaced by the object
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Density
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The density of an object is crucial as to whether
it will float
Density is mass divided by the volume
An object that is less dense than the fluid will
float
An object that is more dense than the fluid will
sink
An object that is equally as dense as the fluid
will neither sink nor float, but remain in the same
position in the water
So how do things float?
If density determines the buoyancy of an
object, what two factors must be
considered to make an object float?
 How do you need to modify these factors
to make an object float?
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Effects of Volume and Temperature
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As volume decreases, pressure increases
As Temperature increases, pressure increases
also
Bernoulli’s Principle Demo- observe and record
in your science journal
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What will happen when I place the ping-pong ball on
the air current?
What will happen if I tilt the air current?
What will happen if I decrease the air pressure?
Chapter Experiment: Build a Boat
Get into your science teams
 Question: How does the volume of water
displaced by a ship relate to the mass of
cargo a ship can carry? Can you create a
ship that can float on water and carry
cargo?
 Hypothesis: If…then…because
 Procedures: Write your own procedures
for this lab
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Build-A-Boat Conclusions
A ship can only carry a certain amount of
cargo safely
 It can carry less high-density cargo than
high-density cargo
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