Solids, Liquids, and Gasses

Ice Breaker
In your new packet, find the first section
that shows solids, liquids, and gasses (the
three boxes). Draw the structure of the
molecules in these three phases in those
boxes. Be sure to label!
Solids, Liquids, and Gasses
Miss Charney
Northville Central School
Solids, Liquids, Gasses
Recall the structure of solids, liquids, and
 Solids- more tightly packed, little
movement, in colder temperatures
 Liquids- more spread out, more
movement, in warmer temperatures
 Gasses- much more spread out, most
movement, with higher temperatures
Kinetic Theory
Kinetic theory is an explanation of how particles
in matter behave
Three assumptions
 All matter is composed of small particles
(atoms, molecules, ions)
 Particles are in constant random motion
 Particles are colliding with each other and
the walls of their container
Little movement
 Tightly packed
 Form into a
arrangement when
in a solid state
More movement
More spread out
Melting Point- temperature
at which a solid begins to
Heat of Fusion- the amount
of energy needed to move a
substance from the solid to
the liquid phase
Most movement
Very spread out
Boiling Point- the temperature
at which the pressure of the
vapor in the liquid is equal to
the external pressure acting on
the surface of the liquid
Heat of Vaporization- the
amount of energy required for
the liquid at its boiling point to
become a gas
What do the following terms mean to you?
(be sure to use the terms solid, liquid, or
 Melting
 Freezing
 Evaporation
 Condensation
Heating Properties of Liquids
Melting- solid to liquid
 Evaporation- liquid to gas
 Condensation- gas to liquid
 Freezing/Solidification- liquid to solid
 Sublimination- solid to a gas
Plasma- matter consisting of
positively and negatively
charged particles.
 These particles collide
with each other at high
speeds, causing large
amounts of light
Examples of plasma include
the Sun, neon lights,
lightning bolts, and auroras
Thermal Expansion
Thermal Expansion- As substances increase
in temperature, they increase in size
As the kinetic energy of a substance increases
(gets warmer), then the particles move farther
away from each other
As the kinetic energy of a substance decreases
(gets colder), then the particles move closer
Why Water is Interesting
The way in which water
is structured, when it
cools, there is a creation
of larger pockets
between molecules
 Compared to water,
these ice pockets are
larger, so that is why
water expands when
you freeze it
Therefore, ice becomes
less dense than water
because of these large
air pockets
That is why ice floats!
Properties of Fluids
 Why is it that very large ships have the ability
to float?
Buoyancy- the ability of a fluid—a liquid or a
gas– to exert an upward force on an object
immersed in it
 If the buoyant force is equal to the object’s
weight, the object will float
 If the buoyant force is less than the object’s
weight, the object will sink
Density and Buoyancy
Think about the following:
 Say you had a 3 cm block of wood and a
3 cm3 block of iron
 Which one would float?
Think about…
 Floating at the top of the pool vs. sinking
towards the bottom
 Which one makes it feel like there is a lot of
pressure on you?
 Driving up and down a mountain
 Your ears pop because of the change in
Pressure- the force exerted per unit area (F/A)
Pascal’s Principle
Blaise Pascal (1623-1662) stated that the
pressure applied to a fluid is transmitted
throughout the fluid
 For example, when you squeeze a balloon on
one side, the fluid (air) is transferred to the
other side
 When you squeeze one end of the toothpaste
tube, toothpaste comes out the other side
 Both examples show how pressure has been
transmitted through the fluid
Bernoulli’s Principal
Daniel Bernoulli (1700-1782) stated that as the
velocity of a fluid increases, the pressure
exerted by the fluid decreases
Challenge: taking a piece of paper in your hands
by the shorter side, attempt to lift the opposite end
The high velocity of the wind blowing across a
paper causes the pressure over the top of the
paper to become low, which results in a rising
of the paper
Ice Breaker
Describe what will happen to this object in
Viscosity- the resistance to flow by a fluid
 Having a “low viscosity” means that
the fluid can flow easily
 Having a “high viscosity” means that
the fluid cannot flow easily