Earth’s Atmosphere

What newsworthy weather events have you noticed in the media?

Weatherbug

• http://achieve.weatherbug.com/Home.aspx# target1 • http://www.wnep.com/weather/regionaldop pleriiradar/

Can you describe what you see in this picture?

In this chapter you will learn about Earth’s atmosphere, and the gases that support life.

Size of the Earth

• 1. Diameter = from the north pole to the south pole it’s ~ 7916 miles • 2. Circumference ~ 24,901 miles •

Equator-

imaginary line that divides the earth into hemisphere’s (north and south)

Tell the person next to you what the 3 most important features of earth

• 1. land lithosphere • 2. air atmosphere • 3. water hydrosphere

Viking---astronomy connection

5-2 Development of Earths atmosphere

Past Atmosphere 4 billion yrs ago

Methane Ammonia

Water

Atmosphere at 3.8 billion yrs. old

New gases

Methane

water water water Water water H H H H 2 0 0 0 0 0 Ozone= 3 oxygen atoms combined together to form a protective layer

• •

Due to the ozone

Blue-green bacteria started to become more abundant • used sunlight, carbon dioxide (co2) and water to make food, their byproduct was oxygen

Present Atmosphere

5-3 Layers of the Atmosphere

What do mountain climbs have to carry as they climb higher into the atmosphere?

La Rinconada, Peru

Layers of the atmosphere depends on

temperature

changes

Troposphere

56 mi.

1. Almost all weather occurs here 31mi.

11 mi.

2. Extends 11miles high 3. Jet stream

Convection currents

Currents of air are produced as warm air rises and cool air replaces it.

Convection currents

• Movement of air caused by a difference in temperature • What’s really happening • Cool dense air is sinking and warm, less dense air is rising, causing a movement of air

Stratosphere

• Lower stratosphere temp. = extremely cold

Stratosphere

• Jet stream winds- strong eastward wind that blows horizontally around the earth

Stratosphere

• Ozone layer Warm = 64° f Cold = -76°f • Ozone ( a form of oxygen, O3) reacts with the uv light to warm the air • Protects earth from harmful uv radiation

Stratosphere

 Temperatures increase as you ascend. Why?

 The Ozone Layer absorbs ultraviolet rays, giving off heat.

 The Jet Stream

Video-15 min

• http://www.youtube.com/watch?v=L4CX7 GL_DPo

Mesosphere

•  coldest area of the atmosphere  Shooting Stars what are they?

Protect us from falling meteoroids

Meteoroids, meteors and meteorites

•

Meteoroid:

An object in space no smaller than a speck of dust and no larger than an asteroid. Most are thought by scientists to be pieces of asteroids or comets.

•

Meteor:

The streak of light that forms when a meteoroid burns while traveling at high speed through Earth's atmosphere (a "shooting star" or "falling star").

•

Meteorite:

The remnants of a meteoroid that has passed through the atmosphere and struck the Earth.

Thermosphere

• • No definite Limit Very Hot? Why • • Nitrogen and Oxygen absorb a lot of UV radiation and convert it to heat Thin air makes seeing objects in space more easily.

• •

Ionosphere

Lower layer of the thermosphere Gas molecules are electrically charged • Radio waves bounce back • Brilliant light displays of aurora borealis occur here

Exosphere • •Outer layer of thermosphere

Thermosphere

•Communicate long-distance telephone and television signals No definite upper limit

Magnetosphere

• • •

Extends above Earth

Magnetic field that traps charged particles from the sun Particles follow the lines of magnetic force and bounce back and forth from one pole to the other • Sometimes breaking through into the ionosphere to produce auroras

Aurora Borealis, Northern Lights