Sunday, November 29, 2009

Phy Science - Weather Review

Check this link to review cloud types. Remember fog is really a ground level cloud.

Middle-latitude cyclone/wave-these are the weather producers in the United States. Every storm system we looked at in Michigan has been associated with these weather producing systems. 

Processes that lift air- be sure to also look at your notes
  • orographic lifting- air rising/dropping over mountains
  • localized convective lifting- clouds forming on warm summer days
  • convergence- Florida peninsula
  • frontal wedging- warm air forced up over colder air

Phy Science - Weather Review

Water Vapor - water vapor is the gas that that drives atmospheric processes. When water vapor condenses around dust, smoke, salt particles (condensation nuclei) clouds can form along with precipitation- rain, snow, sleet hail, etc.
Phase Changes- water can undergo phase changes at the Earth's surface.
  • melting- solid to liquid,
  • evaporation - liquid to gas
  • condensation- gas to liquid
  • freezing- liquid to solid
  • latent energy- the energy that is stored in water, see notes.
Relative humidity- indicates how close the air is to saturation. Warm air can hold more water vapor than cold air. Check notes.
Dew Point- the temperature at which the air needs to be cooled to reach saturation/ clouds can form.
Adiabatic- the cooling/heating of air due to a change in pressure. When air is compresses (higher pressure) it  will warm. When air expands (lower pressure) it will cool.
Wet adiabatic rate-is less than the dry adiabatic rate because of latent heat.

Sunday, November 15, 2009

Phy Science- Temperature Controls

Prevailing Winds.
In the continental United States the prevailing direction of the wind is from west to east. Cities on the west coast/windward side of the continent will have their temperatures moderated by the wind coming off the Pacific Ocean and will have cooler summers and milder winters. Cities on the east coast/leeward side are not influenced as strongly by the Atlantic Ocean as the prevailing wind is blowing offshore.

Below is a map showing lines that connect equal temperatures in the United Sates. These lines of equal temperature are known as isotherms.

Cloud cover also acts as a temperature control. On a cloudy night the clouds act like a blanket absorbing outgoing radiation from the surface of the Earth. The clouds help keep the air temperature higher than on a clear night.

Phy Science- Tepmerature Controls

When looking at the Earth notice that the southern hemisphere is covered with much more water than the northern hemisphere. Due to this large difference in the area covered by water the annual temperature ranges in the southern hemisphere are generally smaller than those in the northern hemisphere. It is interesting to note that cities at the same latitude north and south of the equator, at the same altitude, the southern city will have a smaller temperature range.

Phy Science- Temperature Controls

Temperature controls on Earth are influenced by three factors: altitude, location and heat capacity. If you have had the opportunity to visit the Rocky Mountains in the summer you may see snow on the tops of mountains. This is due to the fact that temperature decreases with altitude. We have discussed in class that water takes a long time to heat up and a long time to cool down, whereas the land heats up and cools down quickly. This ability to absorb heat by an object is referred to as heat capacity. Omaha Nebraska (top graph) is located in the interior of the United States not near a large body of water. Omaha will have extremes in temperatures during the year due to the fact that the land will not retain its heat. The graph below of London, near the ocean will have smaller temperature ranges because of the moderating influence of the ocean. We see this effect in Michigan with temperatures on the Lake Michigan shoreline versus those cities inland.

Phy Science - Transfer of Heat

Heat can be thought of as the motion of particles within a substance. This energy of motion is known as kinetic energy. Heat, energy, always moves from areas of high concentration to areas of low concentration (differences in temperature). The troposphere is heated from the ground up by the re-emitting of solar energy. This heat emitted from the ground is absorbed by gases in the troposphere known as the greenhouse effect.

Energy (heat) is transmitted by three processes:
  • radiation- energy from the sun reaches the Earth through this method.
  • convection - the transfer of heat by the movement of mass in a fluid (water or air).
  • conduction- transfer of heat by molecular movement- one molecule hitting another.

Phy Science - Atmosphere

The Earth's atmosphere is a mixture of gases. The most abundant gas in the atmosphere is nitrogen 78% with oxygen the 2nd most abundant at 28%.

Troposphere- (lowest layer) this is where we live and weather occurs, temperature decreases.
Stratosphere- temperature increases, this layer contains the ozone layer. Ozone is three atoms of oxygen combined and the ozone protects from UV radiation.
Mesosphere- temperature decreases, meteors burn up in this layer.
Thermosphere- temperature increases, beginning of outerspace.

Pauses- these are the boundaries between layers of the atmosphere, see diagram.

Sunday, November 1, 2009

Mid-Term Review

  • centripetal acceleration- is towards the center of the curve
  • acceleration of gravity - is constant
  • gravity caused the formation of the Sun and the planets from a nebula
  • speed=distance/time
  • KE=1/2mv2
  • GPE= mgh
  • terrestrial planets have a solid iron core due their closeness to the Sun (gravity)
  • review phases of the moon material

Mid- Term Review

  • elliptical orbits- to calculate, eccentricty= distance between foci/length of major axis
  • transverse wave- particles move perpendicular to the direction of travel
  • compressional wave- particles move parallel to the direction of travel
  • refraction- the bending of light as it moves from one substance to another
  • diffraction- the bending of a wave around an object
  • EM waves- have an electric and magnetic field
  • distance- how far the route is you take to get some somewhere
  • displacement- how far one travels as "the crow flies"

Mid Tem Review

  • Remember seasons are caused by the Earth's tilt NOT how far the Earth is from the Sun. In the diagram the first day of winter in the northern hemisphere would be on the far left- northern hemisphere is tilted away from the Sun.
  • Blue shift/red shift- red shift is evidence of an expanding universe where a blue shift would indicate a contracting universe.
  • eclipses- review diagrams, lunar eclipse ( Sun-Earth-Moon), solar eclipse (Sun-Moon-Earth).
  • review contour maps
  • amplitude- for a light wave this is brightness, for sound loudness
  • wave speed= frequency X wavelength
  • Doppler effect/shift
  • mass- does not depend on gravity, mass is a property of the object
  • weight- depends on distance from the center of gravity