Heat Energy and Changes of State
and Earth’s Energy Supply
Types of Change of State *Note: Properties of water on ESRT page 1
PHASE CHANGE NAME
Melting
Solidification (Freezing)
Crystallization
PROCESS
MATERIAL
GAIN OR
RELEASE
ENERGY?
Changing of a solid to a Gained
liquid
Changing of a liquid to a Released
solid
Changing to a solid with Released
an ordered pattern
EXAMPLE
Left out ice cream
Making ice cubes
Rock candy
Evaporation (Vaporization) Changing of a liquid to a Gained
gas or vapor
Vaporizer used when sick
Condensation
Changing of a gas or
vapor to liquid
Foggy mirror after
shower
Sublimation
Changing of a gas
Gain if going to Dry ice
directly to a solid or
gas, released if
from a solid directly to a going to solid
gas
Released
It takes much more energy to go from
liquid->gas or gas->liquid than from
solid ->liquid or liquid ->solid
Stored Heat and Changes of State
 A material’s temperature rises as heat is
added to it unless the material is in the
process of changing state, then the
temperature will remain the same as it is
heated
A cheesy 80s video to help explain the concept
 EUREKA!!!
Stored Heat and Changes of State of Water
 Freezing point of water= 0 degrees C
 Boiling point of water= 100 degrees C
 When water reaches 0 degrees C or 100
degrees C, it will remain at that
temperature for a period of time during the
change in state
 This is due to the fact that the heat that is
being added is being changed to stored heat
(potential energy)
Earth’s Energy Supply
 MEMORY JOGGER:
The energy for Earth’s processes comes from mostly the sun
but also Earth’s interior
Solar Energy
 Earth receives electromagnetic energy of
varying wavelengths from the sun
 Solar energy is produced by nuclear fusion
(see notes on the sun in the astronomy unit)
Earth's Own Energy
 Heat energy from Earth’s interior is converted
into mechanical energy for mountain building,
volcanic eruptions, plate movements and other
internal movements
 Nuclear decay (aka nuclear fission): the process
by which unstable elements split to form lighter
elements, resulting in the release of high amounts
of energy
 Nuclear decay is used to produce a portion of the
nation’s electric supply (ie. Indian Point)
EXIT PASS
 In groups of 3-4…
 Write ONLY the process. Be sure all names are on your paper
 Determine the change in state occurring in each of these examples:
 Example: Water turning into ice: liquid->solid (solidification)
a. Dew on a car window
b. A pot of water on a counter going from a level of 2 liters to a level of 1
liter in a period of 3 days
c. A smoke machine at a dance
d. Breathing on a mirror and fogging it up