Ch. 13-4: Ch. 13-4: The Atmosphere The Atmosphere

Characteristics of the AtmosphereCharacteristics of the Atmosphere

• It is a blanketblanket of moisture-filled air that surrounds the earth

• It consists 78% nitrogen, 21% oxygen, 1% other gases (argon, carbon dioxide and water)

• It has ozone in its upper layers which absorb harmful UV rays from the sun

• It protects us from meteors (they vaporize due to the friction with the atmosphere)

• It keeps the earth warm enough for us to live

Layers of AtmosphereLayers of Atmosphere

Temperature GradientTemperature Gradient

• A change in temperature over a distance****In the troposphere the temperature gradient ****In the troposphere the temperature gradient

is -6.5is -6.5°°/km in altitude/km in altitude

Example: What is the temperature at the top of an 8000 m mountain if the temperature is 18°C at

the foot of the mountain?

Layers Again….Layers Again….

Layers in Order…(starting from the Layers in Order…(starting from the Earth upwards)Earth upwards)

1. Troposphere – up approx 12 km1. Troposphere – up approx 12 km• Closest to the Earth’s surface• Where all weather takes place• Air is in constant motion with both vertical and horizontal currents• Pressure decreases as altitude increases• Has very small amounts of ozone

2. Tropopause2. Tropopause• Contains more ozone than troposphere • Is warmer than the troposphere because it absorbs UV rays from

the sun

3.STRATOSPHERE3.STRATOSPHERE• 12-50 km above the

Earth’s surface• Higher levels of ozone

than any other layer

4.MESOSPHERE4.MESOSPHERE• Temperatures are very

low here• 50 to 80 km above the

earth• Very low density• Meteors from space

usually burn up in this layer due to air friction

• Temperatures are very low here

5.Thermosphere 5.Thermosphere AKA –IonosphereAKA –Ionosphere

• 80 km to 500 km from Earth’s surface

• Fewest air molecules• Also called ionosphere b/c

the Sun’s radiation causes particles to become electrically charged ions

• The Northern and Southern lights (aurora borealis) are produced by these ions

• These charged particles also reflect radio signals so they can travel around the World

6. Exosphere6. Exosphere

• Outer limits! SPACE• The thin, outermost layer• Very few particles (few hydrogen particles)

spread out very far

Work on Atmosphere graph activity

THE CARBON CYCLE

CHAPTER 2.5

A Little Background Info …Carbon is an element. Basis of living

things.Organic Substances:• Always contain atoms of carbon and hydrogen

and often contain oxygen and nitrogen atoms.• EXAMPLES:

– Proteins, sugars, and fats

Inorganic Substances:• Matter that doesn’t contain a combination of

carbon and hydrogen atoms • EXAMPLES:

– Carbon Dioxide (CO2), water (H2O), and ammonia (NH3)

CYCLING OF ORGANIC MATTER

• The materials used in building the bodies of living organisms are limited to the atoms and molecules that make up the planet.

• To maintain life, every carbon atom is recycled time and time again into new life forms.

The Cycle of Matter

CO2 + Energy

Plant Leaves

Plant Roots

Inorganic Materials Inorganic

Molecules Bacteria

Rabbit

Fox

Decomposers or Organic MatterFeed Matter

Decomposition

• Organic Carbon is stored in:– Living things

• Inorganic Carbon is stored in THREE places: – The atmosphere– The ocean– The earth’s crust

These storage places are called carbon sinks.

• Carbon is removed from the atmosphere by plants when they photosynthesize to make sugar.

Photosynthesis Reactants Products

• 6CO2 + 6H2O + light C6H12O6 +6O2

Carbon Dioxide + water + light Sugar ( Glucose) + oxygen

• Carbon is returned to the atmosphere by plants and by animals when they respire or exhale.

Respiration Reactants ProductsC6H12O6 + O2 CO2 + H2O Sugar + oxygen carbon dioxide + water

• Photosynthesis and cellular respiration are complementary processes.

• The carbon that they use is repeatedly cycled, thus the name CARBON CYCLECARBON CYCLE.

Atmosphere• Most of the carbon that forms

living organisms is released to the atmosphere or to water, as carbon dioxide from dead, decaying organisms.

Earth’s crust• If decomposition doesn’t

happen, matter may be converted into rock or fossil fuels such as coal, petroleum and natural gas.

• This carbon is not released until the combustion process takes place through burning the fossil fuels.

The Ocean• Carbon is found in sea shells

and bones. When these fall to the bottom of the oceans and get covered with sediment, they decompose over millions of years to form oil (one of the fossil fuels).

•

Shells and Bones (Millions of tonnes of soil)

Sink to the bottom of the ocean

Covered by sediment (Millions of years)

Form oil (example: Offshore drilling NFLD)

Reservoirs for Organic Carbon• Organic carbon is also held in

reservoirs – the bodies of living things.

• All living things die and decomposition eventually returns the carbon to the cycle in inorganic form.

One Important Exception• Bogs – store huge quantities of

carbon in organic form• Bogs have very little oxygen,

therefore decomposition is very slow

• Carbon atoms may remain locked away in dead plant matter (peat) for many years in a bog.

• When plants decompose in a bog, they form peat that can get trapped under sediments over millions of years and form coal (another form of fossil fuel)

PLANTS

Die in a bog and form Peat

Millions of years and tonnes of pressure

form coal

HOMEWORK• QUESTIONS:• Page 65• #1,2,4,5,6a,7ad