Introduction To Weather Introduction To Weather DynamicsDynamics

What do you know about weather?

• Key terms?

• Why is it important?

• How does it affect us?

• How does it affect other animals/plants?

MeteorologyMeteorology

The study of The study of the Earth’sthe Earth’s

atmosphereatmosphere

and weatherand weather

systemssystems..

WeatherWeather

The day to day The day to day changes in thechanges in the

atmosphereatmosphere

at a particularat a particular

locationlocation

on Earth.on Earth.

ClimateClimate

AA

widespreadwidespread,,

long-lasting and long-lasting and recurring recurring

conditions of theconditions of the

atmosphereatmosphere..

AtmosphereAtmosphere

The layer of The layer of gasesgases that surrounds that surrounds planet Earth.planet Earth.

The gases are held The gases are held in place by in place by

gravitygravity..

Heat and Temperature

• To understand weather and climate we must understand temperature and heat!

• What happens when you hold a chocolate bar in your hand?

• THIS IS NOT PART OF THE JOURNAL…

Different ways that heat “moves”

• There are 10 pictures• For each picture determine the following

answers:• A) What makes you think that heat is

moving; is there any evidence that you see showing heat transfer?

• B) Where does the heat come from and where does it go?

1. Your breath on a cold day

2. Hot chocolate

3. Hot soup in a bowl

4. Geysers in Iceland

This whole area is a geothermal park sitting on top of a huge, boiling cauldron. Steam and gas escape from the geothermal system. There are hot springs and mud pots. Mud pots are

often around 70-80’C.

5. Chicks are happy in the winter until their heat lamp

6. The Desert – heat waves create a mirage

7. Baking and Cooking

8. Melting Ice Cream

9. Fireplace

10. Boiling Water

Heat can be transferred in Heat can be transferred in three ways:three ways:

1.1. ConductionConduction

2.2. ConvectionConvection

3.3. RadiationRadiation

1. Conduction – the easy definition1. Conduction – the easy definition

Heat is Heat is transferred transferred through a material through a material

without the material without the material moving. moving.

Only the Only the energyenergy moves. moves.

1. Conduction - complicated1. Conduction - complicated

Heat is transferred from one Heat is transferred from one object to another. object to another.

As one molecule is heated it As one molecule is heated it begins to move and shake begins to move and shake

rapidly. rapidly. It passes some of its heat It passes some of its heat energy to other molecules energy to other molecules

around it. around it. All the molecules of an object All the molecules of an object

pass heat from one to pass heat from one to another, until they are all another, until they are all

hot.hot.

• http://www.s-cool.co.uk/gcse/physics/energy-transfers/revise-it/how-does-heat-energy-move

ConductorsConductors

• SolidsSolids are the best conductors are the best conductors• Solids have atoms that are Solids have atoms that are

closercloser together so the heat is together so the heat is transferred easier.transferred easier.

• In In gasesgases especially the atoms especially the atoms are too far apart.are too far apart.

ConductorsConductors

• MetalsMetals are the best conductors. are the best conductors.• Example: Example: Frying panFrying pan• Example: Example: The expansion joint on a The expansion joint on a

bridgebridge• GasesGases are the worst conductors. are the worst conductors.• Example: Example: AirAir• http://www.wisc-online.com/Objects/

ViewObject.aspx?ID=SCE304

2. Convection – easy defintion2. Convection – easy defintion

Transfer of heat Transfer of heat energy through energy through moving liquids moving liquids

or gasesor gases. .

ConvectionConvection

Hot air Hot air risesrises in cold air. in cold air.

Hot liquid Hot liquid risesrises in cold liquid. in cold liquid.

2. Convection2. Convection

Highly energetic Highly energetic atoms or atoms or

moleculesmolecules

movemove

from one place to from one place to another. another.

• When a liquid or gas heats up, the particles move around more.

• This makes the particles spread out, so they have more room to move.

• This lowers the density of the substance. The hotter it gets, the lower the density goes.

• It is this lower density that makes the hotter substance rise. The cooler substance has a higher density, which makes it sink.

Example of Convection

• The heat in a boiling pot of water (steam)

• The heat in a room that rises to the top of the room

• http://www.wisc-online.com/Objects/ViewObject.aspx?ID=SCE304

3. Radiation3. Radiation

Atoms or molecules Atoms or molecules emitemit

electromagneticelectromagneticwaveswaves. These waves . These waves

carry energy carry energy through space and through space and

deposit it only deposit it only when they interact when they interact with some form ofwith some form of

mattermatter..

Examples: ToastersExamples: Toasters

Sun’s energy (in the Sun’s energy (in the air) that makes us air) that makes us

hotterhotter

Radiation and Colours

• What colours are the best at radiation?– Black and dull colours

These colours absorb and emit heat.

Poor radiation colours: White and shiny colours.

These colours reflect heat.

Keeping the Heat

• Where is heat lost the most?• Why?

• Heat energy is transferred from homes by conduction through the walls, floor, roof and windows. It is also transferred from homes by convection. For example, cold air can enter the house through gaps in doors and windows, and convection currents can transfer heat energy in the loft to the roof tiles. Heat energy also leaves the house by radiation through the walls, roof and windows.

• http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/energy/heatact.shtml

• Now let’s go back to those pictures and determine what type of heat transfer is occurring!

1. Your breath on a cold day

2. Hot chocolate

3. Hot soup in a bowl

4. Geysers in Iceland

This whole area is a geothermal park sitting on top of a huge, boiling cauldron. Steam and gas escape from the geothermal system. There are hot springs and mud pots. Mud pots are

often around 70-80’C.

5. Chicks are happy in the winter until their heat lamp

6. The Desert – heat waves create a mirage

7. Baking and Cooking

8. Melting Ice Cream

9. Fireplace

10. Boiling Water

Quiz

• 1. What substances can convection happen in? – In solids and gases

In solids and liquidsIn liquids and gases

• 2. What type of radiation do all hot objects emit? – Infra-red radiation

Microwave radiationGamma radiation

• 3. What are the best absorbers of thermal radiation? – Light, dull surfaces

Black, shiny surfacesBlack, dull surfaces

• 4. What are the worst emitters of thermal radiation? – Light, shiny surfaces

Light, dull surfacesBlack, dull surfaces

• 5. How does heat pass through a single pane of window glass? – By conduction and convection

By conduction and radiationBy convection and radiation