earth’s atmosphere. nebraska supercell storm cloud - oklahoma
TRANSCRIPT
Interesting Facts…
• The average temp on Earth is 63F (17C)• Ice Age global temp is 54F (12C)
• Due to the Earth’s rotation, our planet bulges out at the equator
• Without plate tectonics, we would overheat– Subduction recycles carbon
Why is our atmosphere important?
• Importance– Makes life on Earth possible– Protective barrier around Earth– Maintains balance between absorbed and heat
lost– Protects life from UV rays
– If we didn’t have one…– We would be burned by the intense heat during
the day and frozen by the low temps at night
I
What is our atmosphere made of?
• Consists of FIVE layers from the surface to space
• Held in place by the Earth’s gravity• As you move upward through the layers,
atmosphere pressure and density DECREASES – Gases– Nitrogen = 78%– Oxygen = 21%– Trace gases = 1% (Argon, Carbon dioxide, ozone)
II
What is our atmosphere made of?
• Solids– Dust – picked up off of the ground– Salt – picked up from ocean spray– Pollen - produced by plants
• Liquids– Water vapor = up to 4%– Sulfuric acid from volcanoes and air pollution
II
What are the 5 layers of our atmosphere?
• Lower atmosphere– Troposphere• Layer closest to Earth• Approx 11 km high• Weather occurs here• Temperature decreases
with altitude• Contains 99% of the
water vapor and 75% of the atmospheric gasses
III
What are the 5 layers of our atmosphere?
• Lower atmosphere
– Stratosphere• Extends 10km to 50km• Airplanes fly here• Ozone layer• Temperature increases
with altitude
III
What are the 5 layers of our atmosphere?
• Upper atmosphere
– Mesosphere• Extends from 50km to 85km• VERY thin and cold• Temperature decreases
with altitude• Meteorites or shooting
stars occur here
III
What are the 5 layers of our atmosphere?
• Upper atmosphere– Thermosphere• Extends from 80km to 500km• The thickest layer• Named for its high temperature• Temperature increases
with altitude• Space shuttles fly in this area• Auroras or the Northern lights
III
What are the 5 layers of our atmosphere?
• Upper atmosphere
– Exosphere• Above a height of 500km• This is where the atmosphere merges into space• Contains very few molecules• Satellites are stationed in this area
III
How is the Sun’s energy absorbed?
• 3 things happen to the energy– About 35% is reflected back into the atmosphere – About 15% of the energy is absorbed by the
atmosphere– About 50% of the energy is absorbed by Earth’s
surface
IV
How is the Sun’s heat transferred through the atmosphere?
• Heat flows from higher temperature objects (roads, rocks, water) to objects with lower temperature (atmosphere)
• 3 ways heat is transferred– Radiation– Heat transfer through empty space– Sun’s energy waves/rays
V
How is the Sun’s heat transferred through the atmosphere?
• Radiation– Electromagnetic waves directly transport energy
through space– Travels through empty space
VI
How is the Sun’s heat transferred through the atmosphere?
• Conduction– Heat transfer between matter– Objects as molecules bump into each other– Air is NOT a good conductor of heat– Least significant is heating the Earth’s
atmosphere
VIIV. How is the Sun’s energy absorbed?
How is the Sun’s heat transferred through the atmosphere?
• Convection– Heat transfer by the movement of mass from one
place to another– ONLY takes place in liquids and gases• Warm air because it is less dense (molecules are
spread out)• Cool air because it is more dense (molecules are
closer together)
VI
What is the water cycle?
• A 3 part cycle describing the constant motion of the hydrosphere (all water on Earth Surface) between Earth and the atmosphere
– Evaporation/Transpiration - Radiation from the sun changes liquid on Earth’s surface into a gas which enters Earth’s atmosphere
– Condensation - Water vapor gas that has cooled and changes back into a liquid
– Precipitation - A collection of tiny water droplets from condensation that collide creating larger droplet which fall to Earth
VII