Homework from last Homework from last class:class:Complete “Thermal energy, kinetic energy,

and potential energy” worksheet (p. 181 in BC Science 10 workbook)

Complete “Thermal energy transfer” worksheet

(p. 182 in BC Science 10 workbook)

Read over class notes and check out the class blog: http://msoonscience.blogspot.com/

The Earth’s The Earth’s AtmosphereAtmosphere

Chapter 10.2 pp. 436-443

Reveal Earth’s Reveal Earth’s AtmosphereAtmospherehttp://www.youtube.com/watch?v=1YAOT92wuD8

Note:Note:Terms in green are definitions

– these are key terms to know

Terms in blue are important words or concepts – please make note

What is an atmosphere?Atmosphere: layers of gases that extend above a planet

p. 436

Energy Transfer in the Energy Transfer in the AtmosphereAtmosphere

The Earth’s atmosphere is a key factor in allowing life to survive on the planet.

◦ The narrow band of air of the atmosphere has the right ingredients and maintains the correct temperature, to allow life to form and survive.

The Earth’s atmosphere originally contained no oxygen and consisted of gases released from volcanic eruptions.

p. 437

Origin of the Earth’s Origin of the Earth’s AtmosphereAtmosphere

Scientists think that oxygen first came from the breakdown of water by sunlight, then later from photosynthesis by micro-organisms and plants.

◦ Eventually, the balance of CO2 to O2 stabilized

o The atmosphere likely contained > 50% water vapour, carbon dioxide gas, sulfur-containing gas, and hydrogen gas

What is air?What is air?Air: a combination of gases in the lower atmosphere, near the Earth’s surface.

Air = 99% nitrogen and oxygen The remaining 1% consists mostly of argon gas and carbon dioxide gas

The density of the atmosphere decreases with altitude. Example: If you climb a mountain, the air becomes thinner the higher you climb hard to breathe in enough O2 p. 437

The composition of Earth’s atmosphere

The Layers of the The Layers of the AtmosphereAtmosphereThe Earth’s atmosphere is made up of 5

layers.

1) Troposphere: the lowest layer of the Earth’s atmosphere, 8 km to 16 km thick Highest density layer (all other layers compress it). Almost all water vapour found in troposphere

location of weather Solar energy and thermal energy from Earth keep

air moving

p. 438

Temperature range:

+15ºC at the bottom to –55ºC at

the top

Bill Nye the Science Guy - Bill Nye the Science Guy - AtmosphereAtmospherehttp://www.youtube.com/watch?v=gGNxYtT_36I

The Layers of the The Layers of the AtmosphereAtmosphere2) Stratosphere: the second layer, above the

troposphere• 10 km to 50 km above Earth, warming from –55ºC

as altitude increases The air is cold, dry, and clean in the stratosphere. Strong, steady winds planes often fly at the

bottom of the stratosphere to avoid turbulent convection currents in the troposphere.

p. 438-439

Ozone layer: located in the

stratosphere; blocks harmful UV radiation from the sun.

The Upper The Upper AtmosphereAtmosphere

3) Mesosphere: 50 km to 80 km above Earth Temperatures are as low as –100ºC This layer is where space debris burns up

when it begins to hit particles. (ex: meteors)

4) Thermosphere: 80 km to 500 km above Earth

Temperatures can reach +1500ºC to +3000ºC Location of the Northern Lights (aurora

borealis) charged particles in Earth’s magnetic field collide with particles in the thermosphere.

5) Exosphere: 500 km to 700 km above Earth where the atmosphere merges with outer space.

The layers of Earth’s atmosphere p. 439

Almost all of the thermal energy on Earth comes from the Sun.• This is only a small fraction of the solar radiation that

reaches Earth.• Most thermal energy is transferred near the equator,

which receives a more direct source of solar radiation.

Radiation and Conduction in Radiation and Conduction in the Atmospherethe Atmosphere

pp. 440 - 441

Angle of incidence

Insolation: amount of solar radiation an area receives, measured in W/m2

Insolation decreases if there are particles of matter (dust, smoke) in the way or if the angle of incidence of the solar radiation is too great.

Solar radiation does not heat the atmosphere directly. The Earth’s surface absorbs solar radiation, heats up, then

radiates the thermal energy into the atmosphere. This provides 70 percent of the air’s thermal energy.

Convection currents in the air spread the thermal energy around.

pp. 440 - 441

The Radiation Budget and The Radiation Budget and AlbedoAlbedoRadiation budget: Earth’s balance of incoming and

outgoing energy

Earth’s radiation budget = heat gained – heat lost

• Incoming short-wave solar radiation is reflected and absorbed to various degrees (see p. 441)

pp. 441-442

The Radiation Budget and The Radiation Budget and AlbedoAlbedoAlbedo: refers to the amount of energy reflected

by a surface.

• Light-coloured surfaces (snow, sand) have a high albedo and reflect energy.

• Dark-coloured surfaces (soil, water) have a low albedo and absorb energy.

p. 442

Homework for next class:Homework for next class:Complete “Layers of the Atmosphere”

worksheet

Complete the Reading Check questions 1-5 on p. 443

Read over class notes and check out the class blog: http://msoonscience.blogspot.com/

Works CitedWorks CitedImages taken from the following sources:http://oilismastery.blogspot.com/2009/12/scientists-admit-earth-

grows.html

http://www.geraldinerichard.com/Digital_Art/Learning_Curve/Entries/2004/12/14_AtmosphereSX.html

http://www.esrl.noaa.gov/gmd/outreach/carbon_toolkit/basics.html

http://www.astrobio.net/amee/summer_2008/Features/PluckingDaisyworld.php

http://www.organiclightsculptures.com/NNP/files/tag-renewable-gasoline.php

http://thisistheendoftheworldasweknowit.com/archives/tag/volcanic-eruptions

http://globalgreenpals.com/2010/08/clean-air-kate-learns-about-ozone-action-days/

http://www.topnews.in/tree/Dubai/Dubai

http://my.opera.com/nielsol/blog/2009/02/13/ice-albedo-feedback