Heat Energy and Changes of State

and Earth’s Energy Supply

PHASE CHANGE NAME PROCESS MATERIAL GAIN OR RELEASE ENERGY?

EXAMPLE

Melting Changing of a solid to a liquid

Gained Left out ice cream

Solidification (Freezing) Changing of a liquid to a solid

Released Making ice cubes

Crystallization Changing to a solid with an ordered pattern

Released Rock candy

Evaporation (Vaporization) Changing of a liquid to a gas or vapor

Gained Vaporizer used when sick

Condensation Changing of a gas or vapor to liquid

Released Foggy mirror after shower

Sublimation Changing of a gas directly to a solid or from a solid directly to a gas

Gain if going to gas, released if going to solid

Dry ice

Types of Change of State *Note: Properties of water on ESRT page 1

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 StateA 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 conceptEUREKA!!!

Stored Heat and Changes of State of Water

Freezing point of water= 0 degrees CBoiling point of water= 100 degrees CWhen 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 EnergyEarth 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 EnergyHeat 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 PASSIn groups of 3-4…Write ONLY the process. Be sure all names are on your

paperDetermine the change in state occurring in each of

these examples:Example: Water turning into ice: liquid->solid

(solidification)

a. Dew on a car windowb. 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 daysc. A smoke machine at a danced. Breathing on a mirror and fogging it up