Weather dynamicsWeather dynamics

Notes 1 – HeatNotes 1 – Heat

Sciences 10Sciences 10

WhyWhy ??????

1.1. Pourquoi des prévisions de météo sont-Pourquoi des prévisions de météo sont-elles souvent incorrectes?elles souvent incorrectes?

2.2. Pourquoi pensez-vous qu’il fait chaud Pourquoi pensez-vous qu’il fait chaud pendant l’été et froid pendant l’hiver?pendant l’été et froid pendant l’hiver?

3.3. Pourquoi pensez-vous que les Pourquoi pensez-vous que les scientifiques prédisent que les scientifiques prédisent que les changements de climat amèneront plus changements de climat amèneront plus de conditions météorologiques sévères?de conditions météorologiques sévères?

HeatHeat

• Thermal energyThermal energy: : the energy of the the energy of the average movement of the particles average movement of the particles (atoms, ions, molecules) of a (atoms, ions, molecules) of a substancesubstance

• HeatHeat:: transfer of thermal energy transfer of thermal energy from one object to another.from one object to another.– Goes from high to low thermal energy Goes from high to low thermal energy

Heat transferHeat transfer

• There are 3 methods of heat There are 3 methods of heat transfer transfer – conductionconduction– convectionconvection

– radiationradiation

ConductionConduction

• Conduction:Conduction: heat heat transfer through transfer through collisionscollisions between between high and low energy high and low energy particlesparticles

• Usually with solids i.e. Usually with solids i.e. a a pot on the stovepot on the stove or or between a solid and a between a solid and a liquid/gasliquid/gas

ConvectionConvection• ConvectionConvection: heat transfer during : heat transfer during

which high energy particles rise. which high energy particles rise. – Hot particles rise (because they are less Hot particles rise (because they are less

dense) dense) – Cold particles fall (because they are more Cold particles fall (because they are more

dense)dense)– This movement creates convection This movement creates convection

currents.currents.

• Usually with liquids and gases – Why Usually with liquids and gases – Why not with solids? not with solids?

RadiationRadiation• RadiationRadiation: heat : heat

transfer through transfer through electromagnetic electromagnetic waveswaves. .

• These waves transport These waves transport energy energy through spacethrough space and release it only and release it only when they interact when they interact with certain types of with certain types of matter matter

• No particles are No particles are necessary for this necessary for this transfertransfer

Air heatingAir heating

• Solar radiation is the primary source of Solar radiation is the primary source of energy that heats soil and water.energy that heats soil and water.

To DoTo Do: (: (Text pText p.435, 438-.435, 438-439)439)

Notes 1A QuestionsNotes 1A Questions