Composition of the Atmosphere Through Time - PowerPoint Presentation

Slide1

Composition of the Atmosphere Through Time

and the Impact on Living ThingsSlide2

Earth’s Atmosphere

The gases that surround Earth (and other planets) make up the atmosphere

These gases are like an envelope that protects us from the radiation that is caused by the sun’s raysThe functions of the atmosphere include protection from the sun, maintaining temperature, and supplying gases necessary for breathing.Slide3

Layers of the Atmosphere

The atmosphere is divided into

four

layers based on

temperature, air pressure, and other

properties

.

Troposphere (closest to Earth)

StratosphereMesosphereThermosphere (ionosphere and exosphere)Slide4

Layers of the AtmosphereSlide5

The Thermosphere

The

thermosphere

is the uppermost layer with temperatures that increase as altitude increases.

Made up of the ionosphere and exosphere

auroras happen in the ionosphere

sattelites orbit in the exosphere

Hottest of the layers

Air is very thin (the air is only about 0.001 percent as dense as the air at sea level) Slide6

The Mesosphere

The

mesosphere

is between the thermosphere and stratosphere.

Temperatures decrease as altitude increases

.

Coldest layer

Meteoroids begin to burn up in the mesosphere

.Radio waves deflected back to Earth in this layerSlide7

The Stratosphere

The

stratosphere

is between the mesosphere and troposphere.

Temperatures generally increase as altitude increases.

Ozone

(O

3

) in the stratosphere absorbs ultraviolet radiation from the sun, which warms the air.Jets fly in this layerJet streams (“rivers of air”) are found in this layerSlide8

The Troposphere

The

troposphere

is the lowest layer of the atmosphere.

Temperature generally decreases as altitude increases. Temperatures near the surface vary greatly.

The troposphere contains 80 percent of the atmosphere’s total

mass.

All

weather happens in the troposphere.Slide9

QUIZ TIMESlide10

What are the layers of the atmosphere?

How do temperatures differ with altitude in the atmosphere?Slide11

EXOSPHERESlide12

MESOSPHERESlide13

THERMOSPHERESlide14

TROPOSPHERESlide15

STRATOSPHERESlide16

THERMOSPHERE

OR THE IONOSPHERESlide17

MESOSPHERESlide18

Atmosphere Over Time

The composition of the atmosphere has changedSlide19

Earliest/First Atmosphere

It is

hypothesized that the earliest atmosphere was composed of mainly H2 and HeMost

likely these gases were lost to

spaceAs this is a hypothesis, percentages are unknownBased on this hypothesis, living things did not existSlide20

Represent with a Graph

Scatter two different colored M&Ms on your pie chartSlide21

Second Atmosphere

There is evidence to suggest that the gases that made up the second atmosphere were

H2O, CO2, SO2, CO, S

2

, Cl2, N2, H2, NH

3 (ammonia), and CH4 (methane) These gases were caused by early volcanoesThis atmosphere contained approximately 90% CO2, 5% N

2, and 2% - 5% trace gases Slide22

Second Atmosphere’s Impact on Living Things

As Earth cooled over time,

oceans formed Oceans are made of H2O (water) This

allowed for the first life

forms -- bacteria These ancient bacteria survived because they used CO2 (carbon dioxide) to photosynthesize

One of the products of photosynthesis is O2 (oxygen gas)Slide23

Represent with a Graph

90% (carbon dioxide)

5% (nitrogen gas)2-5% (trace gases)Slide24

Today’s Atmosphere

Our atmosphere contains approximately

78% N2, 21% O2, and

1% trace gases

N2 remains from the second ancient atmosphereCO

2 levels decreased to approximately 0.03%.CO2 (along with other gases) levels have a large impact on our climate because of its ability to trap heatWithout CO2, the Earth would be approximately 0

oFSlide25

Impact on Living Things

Plants and animals maintain the balance of

CO2 and O2 through the processes of photosynthesis

and

cellular respirationThis allows for the production of oxygen and the consumption of carbon dioxide Slide26

Represent with a Graph

78% (nitrogen gas)

21% (oxygen gas)1% (trace gases)Slide27

What Happens Next?

We will be looking at how human’s have impacted our atmosphere and therefore Earth.

Topics:Global WarmingGreenhouse Effect