PHASE CHANGE

Melting

Boiling

Deposition

Condensation

Evaporation

Freezing Sublimation

Graphic Organizer

PHASE CHANGE

Phase change happens as the temperature

changes.

All matter can move from one state to another.

It may require extreme temperatures or extreme

pressures, but it can be done.

POINTS OF CHANGE

Phase changes happen when certain points are reached.

Scientists use freezing point or melting point to measure the

temperature at which a liquid turns into a solid.

There are physical effects that can change the melting

point.

Pressure is one of those effects. When the pressure

surrounding a substance increases, the freezing point and

other special points also go up.

EXEMPTIONS! -POINTS OF CHANGE

Generally, solids are more dense than liquids because their molecules

are closer together.

The freezing process compacts the molecules into a smaller space.

There are always exceptions in science!!!!

Water is special on many levels. It has more space between its

molecules when it is frozen.

The molecules organize in a specific arrangement that takes up more

space than when they are all loosed in the liquid state. Because the

same number of molecules take up more space, solid water is less

dense than liquid water.

PHASE CHANGE

Phase change requires energy. Heat is

easiest energy that can change the

physical state of matter.

The atom in a liquid have more energy

than the atoms in a solid.

PHASE CHANGE

MELTING

Solids substance turns to Liquid.

When a solid reaches the temperature of its melting point, it can become a liquid. For water, the temperature needs to be a little over zero degrees Celsius (0oC) for it to melt.

LATENT HEAT OF FUSION

It is the change in state

resulting from heating a

given quantity of a

substance to change its

state from a solid to a liquid.

The temperature at which

this occurs is the melting

point.

PHASE CHANGE

FREEZINGLiquid to Solid

The reverse of the melting process is called freezing.

Liquid water freezes and becomes solid ice when the molecules lose energy.

Water turns to ice at 32 degrees Fahrenheit or at 0 degrees Celsius

PHASE CHANGE

BOILING

A liquid boils at a temperature at which its vapor pressure is equal to the pressure of the gas above it.

The lower the pressure of a gas above a liquid, the lower the temperature at which the liquid will boil.

LATENT HEAT OF VAPORIZATION

heat of evaporation, is

the change required to

transform a given quantity of

a substance from a liquid

into a gas at a given

pressure (often atmospheric

pressure, as in STP).

BOILING

PHASE CHANGE

CONDENSATIONthe change of water from its gaseous form

(water vapor) into liquid water.

Condensation generally occurs in the atmosphere when warm air rises, cools and looses its capacity to hold water vapor.

As a result, excess water vapor condenses to form cloud droplets.

CONDENSATION

PHASE CHANGE

SUBLIMATIONSolid become a gas.

The easiest example of sublimation is dry ice.

Dry ice is solid carbon dioxide (CO2). Amazingly, when you leave dry ice out in a room, it will not melt into liquid but it turns into a gas.

Coal is another example of a compound that will not melt at normal atmospheric pressures. It will sublimate at very high temperatures.

SUBLIMATION

PHASE CHANGE

DESUBLIMATION (Deposition)It occurs when a gas becomes a solid without

going through the liquid state of matter.

Frost on winter mornings. The frost crystals on

plants build up when water vapor from the air

becomes a solid on the leaves of plants.