Ch. 13-4: The Atmosphere

Characteristics of the Atmosphere blanketIt is a blanket 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 Atmosphere

Temperature Gradient A change in temperature over a distance ****In the troposphere the temperature gradient is -6.5°/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 in Order…(starting from the Earth upwards) 1. 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. Tropopause Contains more ozone than troposphere Is warmer than the troposphere because it absorbs UV rays from the sun

3.STRATOSPHERE km above the Earth’s surface Higher levels of ozone than any other layer 4.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 AKA –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. 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 (CO 2 ), water (H 2 O), and ammonia (NH 3 )

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 CO 2 + Energy Plant Leaves Plant Roots Inorganic Materials Inorganic Molecules Bacteria Rabbit Fox Decomposers or Organic Matter Feed 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 6CO 2 + 6H 2 O + light C 6 H 12 O 6 +6O 2 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 Products C 6 H 12 O 6 + O 2 CO 2 + H 2 O Sugar + oxygen carbon dioxide + water

Photosynthesis and cellular respiration are complementary processes. CARBON CYCLEThe carbon that they use is repeatedly cycled, thus the name CARBON 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