big ideas about phase change

Big Ideas about Phase Big Ideas about Phase ChangeChange

Phase changes happen...Phase changes happen...

• Between the three states of matter:Between the three states of matter:o Solid, Liquid and GasSolid, Liquid and Gas

• 4 Types of Phase Changes:4 Types of Phase Changes:MeltingMeltingFreezingFreezingEvaporationEvaporationCondensationCondensation

The key to starting a phase The key to starting a phase change....change....• HEAT!HEAT!• More Heat = More Kinetic EnergyMore Heat = More Kinetic Energy• More Kinetic Energy = More Particle Movement More Kinetic Energy = More Particle Movement

Particles and Kinetic EnergyParticles and Kinetic Energy

When particles have more When particles have more kinetic energy:kinetic energy:• more speedmore speed• hit other particles harderhit other particles harder• hit other particles more hit other particles more

often often • ExpandExpand

When particles have less When particles have less kinetic energy: kinetic energy: • less speedless speed• hit other particles less hit other particles less

and not as hardand not as hard• ContractContract

Let's Compare Phase ChangesLet's Compare Phase Changes

Melting - Solid to a Melting - Solid to a LiquidLiquid• Caused by heatCaused by heat• heat = kinetic energyheat = kinetic energy Evaporation- Liquid to a Evaporation- Liquid to a GasGas• Caused by heatCaused by heat• Heat = kinetic energyHeat = kinetic energy

Condensation - Condensation - Liquid to a GasLiquid to a Gas

• Caused by coolingCaused by cooling• Particles slow down & Particles slow down &

contractcontract Freezing - Liquid to a Freezing - Liquid to a SolidSolid• Caused by coolingCaused by cooling• Particles slow down & Particles slow down &

contractcontract

Melting

&

EvaporationCaused by heat---

Condensation

&

Freezing

Caused by cooling & contracting