Phase Changes

Slide Show #2

Skip #1 & #2

• We’ll get to these later.

Review: Kinetic EnergyNot on notes

• Kinetic Energy is the energy of motion. • If an object is moving, or not, it has kinetic

energy. • Particles that make up an object move.

Temperature and Average KENot on notes

• Temperature is the measure of how fast molecules move.

• Heat involves of how fast and how much molecules.

• Kinetic Energy is the energy of motion.

Changing States• Matter changes when heat energy is added or taken away.

• The total energy remains the same. • Law of conservation of energy!!!

Phase Change Terms

• Evaporation – Liquid changes to Gas • Condensation – Gas changes back to liquid. • Freezing – Liquid changes to solid. • Melting – Solid changes to liquid. • Sublimation – Solid changes directly to gas• Deposition – Gas changes back into a solid.

PHASE CHANGES

What’s your point?

• Melting point is the temperature at which a substance melts.

• Freezing point is the temperature at which a substance freezes.

• It is the same temperature!!! (just depends on + heat or –heat).

• Water freezes & melts at 0 degrees Celsius!!!!

What’s your point?• The boiling point is the temperature at which a

substance evaporates. • The condensation point is the temperature at

which a substance condenses.

• Water boils and condenses at 100 oC. (depends on +heat or –heat).

An easy way to remember

Watch it in Action!!!

The Hot Plate!