1. Mr. Fetch's Earth Science Class
Ch 17.1: The Atmosphere
Meteorology
Mr. Fetch's Earth Science Class A+

2. 17.1 Atmosphere Characteristics
Composition of the Atmosphere
17.1 Atmosphere Characteristics
Weather is the condition of the atmosphere measured over a short period of time
Is constantly changing
Climate is based on observations of weather that have been collected over many years.
Climate helps describe a place or region.

3. What is measured regularly?
Temperature
Humidity
Cloudiness
Precipitation
Air Pressure
Wind speed and direction
Weather Bug

4. Mr. Fetch's Earth Science Class
The Atmosphere
A layer of gas that surrounds Earth.
Created long ago by volcanic eruptions.
Held around Earth by gravity.
Regulates Earth’s temperature.
Gravity hold
air around Earth A+
Mr. Fetch's Earth Science Class
Mr. Fetch’s Earth Science Classroom

5. Mr. Fetch's Earth Science Class
The Early Atmosphere
Much different than our atmosphere today.
Not suitable for life: No Oxygen to breathe and no Ozone to protect from sun’s rays.
Lots of Carbon Dioxide
Very little Oxygen
Early Atmosphere
Lots of Oxygen
More suitable for
Current Atmosphere
Mr. Fetch's Earth Science Class
Mr. Fetch’s Earth Science Classroom

6. Mr. Fetch's Earth Science Class
Eventually, organisms called Cyanobacteria started making Oxygen photosynthetically.
That oxygen was used to create Ozone.
Ozone blocked harmful rays from the sun allowing plants to survive on Earth’s surface.
Plants produce Oxygen allowing you and I to live and breathe on Earth.
The Process
Mr. Fetch's Earth Science Class
Mr. Fetch’s Earth Science Classroom

7. Mr. Fetch's Earth Science Class
Composition of the Atmosphere
Components of
the atmosphere
The most abundant gasses in our atmosphere are:
Nitrogen
Oxygen
Argon
Carbon Dioxide
The atmosphere also contains some solids and liquids: Dust Acids Ash
Salt Water Vapor
Mr. Fetch's Earth Science Class
Mr. Fetch’s Earth Science Classroom

8. Mr. Fetch's Earth Science Class
Layers of the Atmosphere
Atmosphere is divided into different layers based on temperature.
Temperature changes as you go up.
Sometimes it INCREASES
Sometimes it DECREASES
Sometimes it STAYS THE SAME
There are 5 layers to our atmosphere, each with different characteristics:
1. Troposphere
2. Stratosphere
3. Mesosphere
4. Thermosphere
5. Exosphere
Mr. Fetch's Earth Science Class
Mr. Fetch’s Earth Science Classroom

9. Mr. Fetch's Earth Science Class
Layers of the Atmosphere
Thermosphere Temperature INCREASES High temperatures Thin air. Feels cold.
Mesosphere Temperature DECREASES
Stratosphere Temperature INCREASES Contains ozone O3 absorbs bad rays Absorption = Warm
Troposphere Temperature DECREASES. Weather occurs here.
ATMOSPHERE
Mr. Fetch's Earth Science Class
Mr. Fetch’s Earth Science Classroom

10. Mr. Fetch's Earth Science Class
Air Pressure
Air pressure is the weight of air pushing down from above.
As you go up, pressure DECREASES.
Air pressure makes air near Earth’s surface DENSE.
Mr. Fetch's Earth Science Class
Mr. Fetch’s Earth Science Classroom

11. 17.1 How do Humans influence our Atmosphere?
Composition of the Atmosphere
17.1 How do Humans influence our Atmosphere?
 Human Influence
Human depletion of ozone by use of chloroflorocarbons (CFCs)
Emissions from transportation vehicles account for nearly half the primary pollutants by weight.

12. Primary Pollutants
Makes no sense without caption in book

13. 17.1 Earth-Sun Relationships
What are two major motions of Earth?
Rotation – Spinning on axis
Revolution – Moving around the sun
Click on Globe!

14. Tilt of Earth’s Axis What creates the Earth’s seasons?
The Earth’s tilt relative to the position to the sun.
This also changes the length of daylight.
Makes no sense without caption in book

15. 17.1 Atmosphere Characteristics
Earth-Sun Relationships
17.1 Atmosphere Characteristics
 Solstices
• The summer solstice is the solstice that occurs on June 21 or 22 in the Northern Hemisphere and is the “official” first day of summer.
The winter solstice is the solstice that occurs on December 21 or 22 in the Northern Hemisphere and is the “official” first day of winter.
 Equinoxes
The autumnal equinox is the equinox that occurs on September 22 or 23 in the Northern Hemisphere.
The spring equinox is the equinox that occurs on March 21 or 22 in the Northern Hemisphere.

16. Solstices and Equinoxes
Makes no sense without caption in book