Physical Science
Chapter 16: Solids, Liquids, and
Gases
There are 4 different states of
matter:
•
•
•
•
A.
B.
C.
D.
Solid
Liquid
Gas
Plasma
Kinetic Theory of Matter
• All matter is made of tiny particles (atoms or
molecules) which are in constant motion.
• How tightly these particles are packed together
and how strongly they are bonded will
determine what state of matter the material is.
• Think of it like a snowball. The more tightly
you pack it, the more strongly the flakes
(particles) are bonded together. Pack it
loosely, and the flakes are more likely to fly
apart (loosely bonded).
• Also, particles vibrate more or move around
more quickly if the matter is heated up.
Conversely they also slow down as they are
cooled.
• Adding and removing heat is the #1 way to
change a material from 1 state of matter to
another. (we’ll talk about this later)
• What is the relationship between the
temperature of the particles and their rate of
movement or vibration?
Solids
• Have a definite shape
and a definite volume
• Particles are tightly
packed and are
bonded together
relatively strongly
• Diamonds form under tremendous pressure,
and therefore their particles (carbon atoms)
are packed very tightly. This is one reason
why diamonds are so hard.
Crystalline and Amorphous Solids
• The particles of many solids are arranged in
definite repeating patterns. These are called
crystalline solids.
• Gemstones, minerals like salt, and safety
glass are all examples of crystalline solids.
They have a predictable pattern of particles.
• Amorphous solids have no definite
structure or arrangement of their particles.
• These materials will break in an
unpredictable manner, with no pattern.
• Examples include plastics, glass, and wax.
Liquids
• Have a definite volume, but no definite shape
(they take the shape of their container)
• Particles move around freely within the liquid.
Viscosity in fluids
• Viscosity is the property of a fluid which
describes how well it will flow
• Low viscosity flows easily, high viscosity is
much thicker.
Gases
• Gases have no definite
volume and no definite
shape (but do have mass).
They simply take the
shape of the container
they are in.
• Gas particles are very
loosely bonded and move
around freely.
• Gases, unlike solids and liquids, are fairly
easy to compress and also readily expand.
That is why we say they have no definite
volume.
• Expansion and contraction of gases explains
why warm air rises and cold air sinks.
• Why does it hurt more to jump onto a
water bed than on an air mattress?
• Plasma, the 4th state of matter, is the most
common state of matter in the universe. It is a
gas-like mixture of positive and negatively charged
particles.
These particles make plasma a high energy state
of matter.
• A plasma TV has a large number of tiny cells
containing xenon and neon gases. When an
electric current is passed through these individual
cells, they give off energy which causes phosphors
inside the cell to give off light. These tiny lights
combine together to produce an image.
Changes of state
• By adding or
removing thermal
energy from a sample
of matter, it is often
possible to cause it to
change from one
state of matter to
another.
Melting and Freezing
• Adding thermal energy
can change some
materials from a solid to
a liquid (melting)
• Removing thermal
energy may change
some materials from a
liquid to a solid (freezing)
• Let's say an ice storm knocks out your
power so you light some candles.
As the melted wax drips off, it solidifies as
it cools. Is this considered freezing?
Condensation & Evaporation
• Changing a gas to a liquid
is called condensation
(loses heat)
• Ex.: breathing on a cold
window, warm air rising and
forming clouds, droplets on a
cold glass, dew
• Evaporation is where a liquid changes to a
gas (gains heat).
• Ex.: steam rising from a hot liquid, sweat
cooling your body, a steam locomotive
• Is boiling the same as evaporation?
• How do the bubbles magically appear
in a pot of boiling water?
Sublimation
• Changing a solid directly to a gas is called
sublimation.
• Examples: dry ice, frost on a window
• This is why you don’t make dry ice bombs!
Thermal Expansion

The volume of an object will
increase as it's temperature
increases, and vice versa (directly
proportional)
Examples of thermal expansion:
Shrink Fitting
Laws and Principles
Boyle's Law - for a gas at a constant
temperature, if you increase the pressure
on the gas, the volume will decrease,
and vise versa (ind. prop.)
Ex.: -step on a Pringle's can
-squeezing a balloon
A whoopie cushion utilizes Boyle’s Law.
Charle's Law
• For a gas at a constant pressure, if you
increase the temperature, then the
volume will increase, and v/v.
• Ex.: Hot air balloon, car tires
• Charles Law is similar to what other
concept which we have discussed this
chapter?
Pascal’s Principle
• Pascal’s Principle states that pressure exerted
on a fluid is transmitted equally throughout the
fluid.
• As a downward force is applied to the piston,
the increased pressure is transmitted
throughout the entire system.
P = F/A
and
P=
F/A
10 Pa = 50 N/5 m2 and 10 Pa = 500N/50 m2
Examples:
-squeezing a tube of toothpaste
-The Blob
-Pressurizing the cabin of an
airplane
• Carlos made a balloon rocket as shown in the
picture. According to Pascal’s Principle, what
would happen if the rocket had an opening on
both ends instead of just the one. Explain.
Bernoulli's Principle
• If you increase the speed of a
fluid moving over the surface
of a material, the pressure will
decrease as a result (i.e. fluid
velocity and pressure are
indir. prop.)
• Ex.: Airplane wing, frisbee,
fan blade, treading water
Venturi Effect
• If a moving fluid is forced to travel in a
narrower path, the velocity of that fluid will
increase
• Ex.: Spitwad, nozzle on hose, sand blasting
Archimede's Principle
• The buoyant (upward) force on an object
submerged in a fluid is equal to the weight of the
fluid displaced by that object.
• Buoyancy is the ability of an object to rise or float in a
fluid.
• Ex.: underwater handstand,
lifting a submerged rock,
finding your weight in a
vacuum.
• Let’s say you accidentally fill your bathtub
all the way full. So you know when you
get in, some of the water will have to
overflow.
• If you were to collect all of the water that
overflowed and weigh it (in Newtons), then
that would be the amount of buoyant force
pushing up on you in the tub.
• So if you weight 668 N (about 150 pounds), and
the water which you caused to overflow
(displaced) weighed 620 N (about 139 pounds), then
your weight as you sit in the tub would be
about 48 N (11 pounds), if you were sitting on a
scale on the bottom of the tub.
Buoyant Force h
-_______________________
Weight i
Net Force
• So if you lifted a 200 pound rock
underwater, which displaced 160 pounds
of water, how much it would make the rock
seem to weigh?
• Larry is driving down the interstate, and pulls out
into the left-hand lane to pass a semi. When he
gets right alongside the semi, he notices a strong
force seeming to pull him toward the truck. The
force disappears once he is past the truck.
What produced this force?
• Mark is not real bright. In an attempt t blow out
the candles on his birthday cake, he reasoned
that the more air he could expel, the more likely
the candles are to go out. So he opened his
mouth as wide as possible, and blew. Problem?
• Carl is going to take a hot bath after a hard
practice. He noticed that the bar of soap he
put in the tub sank to the bottom, but when he
added a lot of epsom salt to the water (used to
relieve muscle aches), the soap slowly floated
to the top. Explain why this happened.
Helicopters produce lift by forcing air to move over
their angled blades. This creates a low pressure
area over the top of the blades, allowing the copter
to rise.
Recent technology, however, has allowed designers
to create helicopters which can fly upside down.
How could that happen?
• Bud chugs a bottle of Pepsi. He knows that
he may belch some after doing this because
of the carbonation in the soda. However, he
continues to belch on and off for the next 10
min. How could such small bubbles produce
so much belching?
1. As a hot air balloon rises higher in the
atmosphere, the balloon itself will gradually
grow smaller, and as a result support less
weight.
2. A salvage ship is using a large crane to lift
the hull of a sunken ship out of the ocean.
The ship is able to lift the hull to the surface,
but is unable to lift it any further above the
water.
Iron is much denser than water, yet Bob claims
to have discovered a way to make iron float in
water without attaching anything to the iron to
help keep it afloat. Hmmm…….
• The rear opening on a jet engine where the
hot gases are expelled is usually tapered, or
narrower than the rest of the engine. Why
do you think this is so?
• For an outdoor wedding, the wedding planners
inflated the balloons the day before and put
them in place. When they came in the next
morning, the balloons were half flat.
“Don’t worry” the planners told the family, “the
balloons will be fine when the ceremony starts
this afternoon.”
Why were the
planners so sure
that everything
would be ok?
As a river flows from left to right as shown below,
which way will the water move through the
off-chute (A), clockwise or counterclockwise?
Why?
A bathtub is filled to the brim with water,
and a large chunk of ice floating in it. If
the ice were to melt, would the water level
in the tub raise, lower or stay the same?
Explain why, using a law or principle.
• Some bread doughs come in sealed tubes
which require the user to twist the tubes in
order to pop them open. Which law or
principle explains why this occurs?
• As you prepare to go scuba diving, you
have 2 tanks, one full of compressed air
and the other one empty. However, you
don’t know which is which, so you toss
them both into the water to see. What will
be the difference, and why?
• A hydrofoil is a watercraft designed to
ride up out of the water when it reaches
high speeds. How is this accomplished,
and why?
If a passenger jet
were to suddenly
have a window
break out, materials
inside would
immediately start to
get “sucked” out of
the window. Explain
why this would
happen, using one
of the laws or
principles we have
discussed.
Carl found that if
he squeezed the
sides of his juice
box, the liquid
would shoot up
out of the straw.
Explain why.
• Many people think that oxygen gas is
flammable, and that is why oxygen tanks
have a warning label on them cautioning
people that they are combustible. What is
the real reason they have this warning?
1. According to Archimedes’ Principle, the buoyant (upward)
force exerted on an object submerged in a fluid is equal to
the weight of the fluid displaced by the object. With this
being the case, explain why it is easier to float in salt water
than pure water.
2. If a passenger jet were to suddenly have a window break
out, materials inside would immediately start to get
“sucked” out of the window. Explain why this would happen,
using one of the laws or principles we have discussed.
3. As the gym bleachers were being put up, a basketball
accidentally got caught behind them and was popped.
Explain how this occurred using one of the laws or
principles we have discussed.
4. Lenny turned on his front porch light (outside light) one
morning when it was extremely cold outside. After about
30 sec., the glass of the bulb broke. Explain why.
5. A steamroller applies a force of 6,900 N over
an area of 3 m2. How much pressure is it
creating?
6. State the Venturi Effect and give 2 examples.
1.
2.
7. Helium tanks are often used to inflate
balloons. The tanks usually will have a warning
label which gives a particular temperature range
in which they are to be stored. Explain why.
8. Carl found that if he squeezed the sides of his
juice box, the liquid would come up out of the
straw. Explain why.