2.  Invisible mixture of gases  Nitrogen & Oxygen most common in lower level  Hydrogen more common in upper atmosphere  Water Vapor & Carbon dioxide in smaller amounts  Other materials  Salt  Rock particles & dust

3.  1 st Layer (bottom) : Troposphere  Height from Earth is 7km to 16 km  Temperature around 65ºF  Air pressure & density decreases as you go up  Tropopause: boundary  2 nd Layer Stratosphere  Height 50 km from the troposphere  Temperature 55º F  Upper region contains oxygen (ozone layer)  Absorbs UV radiation

4.  Stratopause: Boundary  3 rd Layer: Mesosphere  Height from stratosphere is 80 km  Temperature 100º F  meteors burn up in this layer  Mesopause: Boundary  4 th layer: Thermosphere  Height from Mesosphere about 500 km  Some space craft orbit here  Absorbs a lot of radiation  Temperature 1000 ºF  Contains ionosphere  Electronically charged particles (ions) are in place by Earth’s magnetic field  Radio signals can be reflected

5.  Thermopause: Boundary  5 th Layer: Exosphere  Extends into outer space  Satellite orbit here  Van Allen belts found here (collects radiation from sun to protect us)

6.  Radiation: energy that travels in the form of waves (a wave is a carrier of energy)  Earth & atmosphere are heated by radiation  Is absorbed or reflected  Wavelength: distance from the crest of one wave to the crest of another wave  Waves with short wavelengths have more energy than waves with long wavelengths

7.  Radiant Energy  30 % is reflected back by the atmosphere, clouds & Earth’s surface  20 % is absorbed by atmosphere  50 % is absorbed by Earth’s surface  The surface cools, long waves of energy are given off  The surface warms, it absorbs long waves of energy (greenhouse effect)

8.  Greenhouse Effect: the rise in temperature that the Earth experiences because certain gases in the atmosphere trap energy from the sun.  Without these gases, heat would escape back into space and Earth’s average temperature would be about 60ºF colder.  Greenhouse gases: water vapor, carbon dioxide, nitrous oxide, and methane  Runaway Greenhouse Effect: could cause melting of glaciers, burns off protective atmospheric layers, rise in oceans  occurs on planet Venus

9.  As radiant energy is absorbed by the earth or atmosphere, it moves from high concentration to low concentration  1. Conduction: heat moves from one object to another while in contact with each other  2. Convection: heat energy is moved by a carrier (ex: water, wind)  Convection current: continuous movement of air (think of convection currents in Earth’s mantle)

10.  Dew point – temperature to which air must be cooled to become saturated. (it will rain)  - When relative humidity (amount of moisture in air) is high dew point is close to air’s temperature.  * Temperature doesn’t need to be lowered much for saturation.  * If relative humidity is lower; dew point is much less than air temperature  so need a large decrease in temperature for saturation

11.  The water cycle has no starting or ending point  96% of Earth’s water is in the ocean  The Sun drives the water cycle as it heats Earth’s oceans and rivers  Evaporation: water that is heated turns into a gas (water vapor) and enters Earth’s atmosphere  Sublimation: ice and snow can be directly turned from a solid into a gas

12.  The process of evaporation from plants is called transpiration. (In other words, it’s like plants sweating.)

13.  As water (in the form of gas) rises higher in the atmosphere, it starts to cool and become a liquid again. This process is called condensation.  When a large amount of water vapor condenses, it results in the formation of clouds.  You can see this at home when you take a shower and the windows and mirrors in the bathroom fog up. You can also do this by breathing on a mirror.

14.  Precipitation occurs when so much water has condensed that the air cannot hold it anymore. The clouds get heavy and water falls back to the earth.  Forms: rain, hail, sleet or snow

15.  When rain falls on the land, some of the water is absorbed into the ground forming pockets of water called groundwater. Most groundwater eventually returns to the ocean.  Other precipitation runs directly into streams or rivers. Water that collects in rivers, streams, and oceans is called runoff.

16.  Runoff, and ground-water seepage, accumulate and are stored as freshwater in lakes.  Not all runoff flows into rivers, though. Much of it soaks into the ground as infiltration.  Some water infiltrates deep into the ground and replenishes AQUIFERS (saturated subsurface rock), which store huge amounts of freshwater for long periods of time.

17.  Over time, though, all of this water keeps moving, some to reenter the ocean, where the water cycle "ends"... oops - I mean, where it "begins."

18. Process to form rain.  A. Warm-cloud process  - tiny droplets form by condensation and then grow by bumping into and combining with other droplets.  - different sizes are more likely to join than same size.  - in the cloud longer, larger droplets.  - larger droplets grow around a large salt nuclei.  ( condensation nuclei)  - droplets shrink from evaporation when falling.

19.  B. Ice process  - in upper layer of clouds  - super cooled water evaporates quickly and deposits on the ice crystal.  - larger ice crystals get heavy enough, the start to fall.  - as they fall they will melt with warmer temperatures.

20.  Clouds- water droplets and /or pieces of ice floating in atmosphere.  - most form in troposphere  - indicated direction and speed of wind and amount of water vapor by shape and position.  *For water to condense from air  1. air must contain water vapor  2. condensation nuclei (dust in air)  3. air temperature must drop to the dew point.

21.  * Air cools by:  1. Coming into contact with cool surface.  ex. Cold water  2. As heat radiates from it into space.  ex. Fog forms in early morning after clear nights temp.  near ground decreases to dew point.  ( fog is cloud near ground)  3. As air rises it cools  ex. Clouds form when air rises to dew point. Causes flat bases on clouds  Temperature changes occurring without heat – adiabatic changes.

22.  Clouds: named by shape.  1. Cumulus- heaped, fluffy clouds often flat base.  Form- warm air rises, only when temperature falls to dew point.  Found- all altitudes  Shows- fair weather  below 2km and 7km are altocumulus  above 7km are cirrocumulus.   - may extend into atmosphere this forms thunder heads- cumulonimbus  May bring violent weather. (thunder, hail, lightening and tornadoes)  * nimbus or nimbo- cloud is precipitating.

23.  2. Stratus- spread out where large body air slowly lifted.  - indicate rainy weather  - block sun for long periods of time  below 2km and 7km are altostratus.  above 7km are cirrostratus  * cirrostratus causes a halo around sun or moon.  Nimbostratus- light but steady rain or snow that lasts more than a day.  3. Cirrus- feathery at high altitudes.  thin and wispy  Form- temperature is below freezing- made of ice crystals.  Found- where air is thin  Shows- fair-weather

24.  Cirrus clouds followed by cirrostratus- rainy period, temperature increases.  Cumulus followed by Cumulonimbus- short period of heavy rain and temperature decreases.