atmosphere • definition: the layer of gases that surrounds the Earth • weather: the condition of Earth’s atmosphere at any given time or place
What gases are in our atmosphere? • nitrogen (N2) = 78% • oxygen (O2)= 21% • trace gases= 1% • argon • CO2 • neon • methane • krypton • hydrogen
What are some sources of carbon dioxide (CO2) in our atmosphere? • burning fossil fuels releases CO2 into the atmosphere • Greenhouse Effect- CO2 and other gases act as a blanket to hold in heat close to Earth
What else is in our atmosphere? • Water vapor- from evaporation and transpiration (1 tree gives off 40,000 gallons of water vapor in a year!) Solid particles (particulate matter)- dust, smoke, pollen, salt, NOX, VOX- from car exhaust, burning and volcanic eruptions
ozone • O3- a form of oxygen with 3 atoms of oxygen instead of 2 • the layer of ozone in the atmosphere absorbs UV radiation from the sun and heats the Earth
Learn more about the ozone layer: • http://www.brainpop.com/science/earthsystem/ozonelayer/
air pressure • definition- the weight of a column of air pushing down on an area • More dense air has higher air pressure than less dense air. • barometer- an instrument used to measure air pressure
air pressure animation • http://www.classzone.com/books/earth_science/terc/content/visualizations/es1901/es1901page01.cfm?cha
units for measuring air pressure • inches of mercury- used with a mercury barometer • millibars- used on National Weather Service maps
altitude • definition- the distance above sea level • The higher the altitude the lower the air pressure. • animation: http://www.phschool.com/webcodes10/index.cfm?fuseaction=home.gotoWebCode
properties of air: 1. mass- even though you can’t see it, air has mass How much mass did our balloon have? How much mass did it have with air blown inside? How much was the mass of the air only? 2. density- the density of air near Earth’s surface is greater than its density at high altitudes 3. pressure- air exerts a force called pressure
Notes Quiz • What is the most abundant gas in our atmosphere? • 2. What are some trace gases that are in our atmosphere? (name 3)
3. What is ozone?a) liquid oxygenb) oxygen molecule with 3 atoms of oxygen instead of 2c) a form of rust 4. What are some of the solid particles in air? (Name 4)
5. Why would there be more water vapor in a tropical rain forest than in a desert?a) the climate is wet in a rain forest and a lot of water would evaporateb) there would be a lot of transpiration from the treesc) both a and b
6. What is air pressure? • 7. In what 2 units is it measured? • 8. How is air pressure affected by density?
9. How is air pressure affected by altitude?10. Does air have mass? How do you know?