Composition Earth Science / Mr. Bimber Earth’s Atmosphere Composition Earth Science / Mr. Bimber
What’s in the air? The atmosphere is: 78% nitrogen 21% oxygen 1% argon 0.04% carbon dioxide Varying amounts of: water vapor pollutants dust
What are the different layers? Outer Space (Exosphere) Thermosphere Mesosphere Stratosphere Troposphere Solid earth
Troposphere Has most of the air Higher it’s cooler Most clouds are here Storms happen here 9-16 kilometers high Bottom layer
Stratosphere Second lowest layer 10-50 kilometers high Has cool, dry air Above the clouds Higher its warmer Ozone layer heats it Some planes fly here
Mesosphere “meso” means middle 50-90 kilometers high Higher it’s cooler again Top is -110 Fahrenheit
Thermosphere Above Mesosphere About 100 kilometers Friction with solar wind causes “northern lights” Higher it’s warmer again “thermo” means hot Top is 1,800 Fahrenheit
Exosphere Top layer Above 100 kilometers Fades out to nothing
How was our atmosphere formed? Comets and meteors Earth melted inside Volcanoes erupted Gases Steam Rivers, lakes, oceans Plants Released oxygen First animals Life possible on land
Is our atmosphere changing? Big meteors Fires, tidal wave Dust Block sunlight Cools the planet Extinction Dinosaurs Us? Industry (humans) CFCs Ozone hole Acid rain Smog Carbon dioxide climate change
Why are there layers? Temperature changes: Outer Space Cooling Heating Solid Earth
How does heat move? Conduction Convection Radiation Atoms bump each other. Convection Hot atoms expand and flow upward Radiation Waves travel through space
Conduction Heat = energy of atoms vibrating. When fast moving atoms speed up their slow neighbors, that’s conduction. Mostly solids, liquids Metals conduct heat faster than wood.
Convection Hot gases and liquids expand and float up. Cold gases and liquids shrink, and sink. Heat travel by flowing atoms is called convection. “Heat rises” - that’s why flames point upward.
Radiation Heat can travel in waves, like light. This is called radiation. Radiation from the sun is called insolation (short for INcoming SOLar radiATION ) Earth radiates some heat out to space.
Heat flows through the atmosphere Temperature changes differently in each layer. The air is heated: At ground level In the Ozone layer By friction with solar wind
Heat in the Atmosphere The balance and flow of heat energy in the atmosphere Causes weather Protects life on earth