Phase Changes
“It’s just a phase”
States of Matter
 Solid,
liquid and gas (plasma)
 Changes between states are called
“phase changes”
 Caused by a change of heat or
pressure
 HEAT and TEMPERATURE are not
the same thing
Temperature
 Measures
the average kinetic energy
of the particles in a substance.
 Is measured in Celsius or Kelvin.
 Kinetic energy is directly related to
the speed of the molecules.
 The faster the particles/molecules
are moving the higher the
temperature.
Heat
 Heat
is a measure of energy
(Joules).
 HEAT and TEMPERATURE are not
the same thing.
 Ex. A cold Lake Superior has more
heat energy than a boiling pot of
water.
 For our class, higher temperature
means more heat.
STATES OF MATTER
Solids
 Molecules
are tightly packed
together.
 High potential energy – more bonds.
 Particles vibrate in place.
 Very Dense.
 Not easily compressed.
 Definite shape and volume.
Liquids
 Particles
are not so tightly packed
(liquids flow and can be poured).
 Medium potential energy.
 Definite volume
 Indefinite shape (takes shape of
container)
Gases
Particles spread out as
the container will allow.
 High kinetic energy,
particles are moving
very quickly
 Can be compressed
 Indefinite volume and
indefinite shape

Phase Changes
When a substance changes states.
 Requires the input or the removal of
energy or change in pressure.
 During a phase change the
temperature does not change, but the
amount of energy does.

Sublimation
Transformation of a substance to a gas
from a solid state with no liquid
transition.
 Dry Ice does this.

Deposition
When a gas transforms into a solid
without transitioning through a liquid
state.
 Ex. Frost forming on windows.
