The Atmosphere Chapter 17 Ch. 17
Today we will be studying our atmosphere, so let’s tie it together with our old content Ch. 17 When Earth first formed ____ billion years ago during the ________ Eon, no ________ was in our atmosphere, therefore there were no living organisms!
Ch. 17 Today we will be studying Earth’s atmosphere the atmosphere is made of air the composition of our air varies, but it is mainly 99% Nitrogen and Oxygen
The other 1% of our air is made of Argon, Carbon Dioxide (CO2), and other gases Ch. 17
There are often small amounts of other substances in our atmosphere, these include: • Water vapor (depends on clouds/precipitation) • Dust • Ozone • Sea salts • Fine soils • Smoke and soot from fires • Pollen • Ash and dust from volcanoes Ch. 17
Sometimes humans even can impact what our atmosphere is made of Ch. 17 Can you think of any ways humans impact what is in our air? • Emissions from vehicles • Sulfur dioxide from generation of electricity
Ozone (O3) vs. Oxygen Gas (O2) Ozone is a gas that protects life on Earth from harmful UV radiation from the Sun it is mainly found in the stratosphere, 6-30 miles above Earth’s surface Ch. 17
How is Ozone made? sunlight splits O2, into two separate atoms 2. One new O atom collides with an O2 molecule 3. New O3 molecule formed
Structure of the Atmosphere Earth’s atmosphere gradually thins to outer space…noclear boundary Ch. 17
Pressure & Temperature as the altitude increases, the pressure decreases Ch. 17
Pressure & Temperature there are 4 layers based on temperature changes Ch. 17 Is this something I should remember? Troposphere Stratosphere Mesosphere Thermosphere
1. Troposphere • Temperature decreases as altitude increases • Layer of atmosphere where weather occurs • Thickness ~ 0-7.5 miles • Temperature goes from ~ 70° F to -70° F Ch. 17
2. Stratosphere • From 7.5-12.5 miles the temperature is constant, then from 12.5- 31 miles temperature rises • Temperature goes from ~ -70° F to 32° F Ch. 17 Hey Mom, why does temperature rise? Temperature rises because this is the layer where we find the Ozone layer…and remember, Ozone absorbs UV radiation from the Sun
3. Mesosphere • Temperature decreases as altitude increases • Thickness goes from 31-50 miles • Temperature goes from ~32° F to -140°F Ch. 17
4. Thermosphere • Temperature rises in this layer because absorption of solar radiation • Thickness≥50 miles • Temperature goes from ~ -140° F to 120° F as altitude increases Ch. 17
Today’s Assignment Today you will be creating in groups of four. You need to: • create a model of Earth’s atmosphere that is to scale (within the best of your ability) • The model needs to include altitude, temperatures, names of layers, and any other identifiable features • Be creative and everyone needs to be working in your group!