Added weather_atmosphere

app/controllers/lesson_controller.rb

@@ -16,6 +16,10 @@ def rock_cycle
     @sections = []
   end
 
+  def weather_atmosphere
+    @sections = %w(solar_energy wind pressure storms humidity)
+  end
+
   def index
   end
 

app/views/lesson/index.html.haml

@@ -9,3 +9,6 @@
     %li
       %a{:href => "/lessons/rock_cycle"} Rock Cycle
       \- targeted for 5th to 8th graders
+    %li
+      %a{:href => "/lessons/weather_atmosphere"} Weather Atmosphere
+      \- targeted for 5th to 8th graders

app/views/lesson/weather_atmosphere.html.haml

@@ -0,0 +1,71 @@
+= javascript_include_tag "lesson"
+= stylesheet_link_tag "lesson/matter"
+-content_for :content do
+  %h2 Atmosphere/Weather
+
+  %p
+    The earth is surrounded by a hugh mass of gases called the atmosphere. It extends outward for approximately 100,000 miles; it consists of gases that cannot be seen; gases have volume and weight. These gases are held in place by the earth’s gravity.
+
+  %p
+    In 1752 it was found that air contained CO2, and within the next 20 years Nitrogen and oxygen were also found.
+
+  %p 
+    Composition of the atmosphere:
+
+  %ul
+    %li Nitrogen  -- 78%
+    %li Oxygen -- 21%
+    %li Carbon Dioxide -- .03%
+    %li Argon -- .93%
+
+  %p
+    (Joseph Priestly discovered Oxygen.)
+
+  %p
+    Water vapor is also found in the atmosphere; it depends on temperature; varies from 0 to 4%. Also part of the atmosphere are solid and liquid impurities called pollutants. Solid pollutants are called Particulate Matter.
+
+
+  %h3 Structure of the Atmosphere
+
+  .illustration
+    = image_tag "/assets/weather_atmosphere/structure-of-the-atmosphere.png"
+
+  %p Troposphere: 
+
+  %ul
+    %li extends upward about 7 miles.
+    %li contains 75% of gases in the atmosphere
+    %li all weather occurs here
+    %li as we go higher the temp. decreases at a rate of 3.5°F / 1000feet or 6.5 deg. F/1000 meters. This is known as the Normal Lapse Rate.
+
+  %p Stratosphere: 
+
+  %ul
+    %li about 43 miles thick
+    %li calm air  -- no storms
+    %li free from dust & water vapor
+    %li found here is the Jet Stream
+
+  %p Mesosphere: 
+
+  %ul 
+    %li contains ozone (O3)
+    %li blocks out ultraviolet light from the sun                                                                   
+    %li a small amount of UV light gets through and  gives you a sun tan.
+
+  %p Ionosphere: 
+
+  %ul 
+    %li about 250 miles thick
+    %li reflects radio waves
+
+  .illustration
+    = image_tag "/assets/weather_atmosphere/radio-signals.png"
+
+  %p
+    During the day radio signals bounce off the lower layer of the ionosphere back to earth. At night the molecules in the lower layer spread apart and the radio signal can go higher into the atmosphere. The signal will then be reflected by a second layer. This will cause the signal to travel further on the surface of the earth. This is why at night you can hear radio stations that are further away.
+
+  %p Exosphere: 
+
+  %ul
+    %li Van Allen’s Radiation belt found here; made up of charged particles. These particles come from the Sun and are trapped by Earth's magnetic field. As they fall through the atmosphere, they burn up giving rise to the Aurora Borealis (northern lights).

app/views/lesson/weather_atmosphere/_humidity.html.haml

@@ -0,0 +1,21 @@
+%h2 Humidity
+
+%p The amount of water vapor in the air is referred to as its humidity.
+
+%p
+  The direct measurement of the water vapor in a certain volume of air is called the absolute humidity.
+
+%p
+  The capacity of air to hold water vapor changes with its temperature . Warm air can hold more water vapor then cold air. The amount of water vapor that a given amount of air can hold at any particular temperature is called its saturation value.
+
+%p
+  The humidity of air is often expressed by comparing its absolute humidity to its saturation value. This method of stating the moisture content of the air compared to the amount which could be contained at a given temperature is called Relative Humidity. To measure Relative Humidity we use  a Psychrometer or hair hygrometer.
+
+%h3 Condensation
+
+%p Condensation is when water vapor changes back to a liquid or solid.
+
+%p Dew Point: the temperature at which a given quantity of air reaches 100%  relative humidity.
+
+%p
+  Dew: the ground temperature falls below the dew point and droplets of water condenses on grass, leaves, etc. If the dew point falls below the freezing temperature of water, water vapor will condense directly into ice in the form of Frost.

app/views/lesson/weather_atmosphere/_pressure.html.haml

@@ -0,0 +1,32 @@
+%h2 Pressure
+
+%p
+  Since the Earth is surrounded by an atmosphere that is about 100,000 miles thick, it exerts a pressure on the ground and the objects on the ground. For each square inch of surface near sea level, air pressure exerts a force of 14.7 lbs. As you rise higher in the atmosphere the air pressure decreases. 
+
+%p
+  We say that water boils at  212°F. But this is only at sea level. As you go higher in the atmosphere water boils at a lower temperature. Denver, Colorado is called the mile high city because it is 5,280 feet above sea level (exactly 1 mile). In Denver, water boils at 202°F.
+
+%p
+  An instrument which measures air pressure is called a Barometer.
+
+.illustration
+  = image_tag "/images/mercury-barometer.png"
+
+%p
+  As the air pushes down on the mercury, the mercury rises in the glass tube. You could use water rather then mercury but the tube would be much longer. (water 34 ft; mercury 3ft)  
+
+%h3 Activity
+
+%p
+  Take an empty 2 liter pop bottle and put about 1 inch of hot water in it. Put you hand over the opening and shake vigoressly for a second or two. Take your hand off and screw the cap on tight. Place the bottle on a table and watch. It may take a few minutes, but the bottle will begin to be crushed. Have the students explain why the bottle got crushed.
+
+%p
+  When you put the hot water into the bottle, the air inside the bottle heats up and expands. The expanding air pushes some of air out of the bottle. When the cap is screwed on, no air can get in or get out of the bottle. As the bottle cools, the air inside the bottle cools and begins to shrink. Atmospheric pressure on the outside of the bottle is 14.7 lbs/sq in (this is at sea level). On the inside of the bottle, it is much less. Since the outside pressure is so great, the bottle is being pushed inward (crushed) by the air pressure. This not only works for 2 liter pop bottles but also for 55 gallon drums.
+
+%h4 Aneroid Barometer
+
+.illustration
+  = image_tag "/images/aneroid-barometer.png"
+
+%p
+  As the air pressure changes, the air inside of the jar tries to get out or the outside air pushes to get in the jar. This causes the straw to move up or down. If the straw moves up, this tell you that a High pressure system is here. If the straw moves down, a Low pressure system is here. A High tells you fair weather is coming; a Low tells you poor weather (cloudy, rainy --snow if it’s too cold) is coming.

app/views/lesson/weather_atmosphere/_solar_energy.html.haml

@@ -0,0 +1,109 @@
+%h2 Solar Energy
+
+%p
+  Almost all of the earth’s heat comes to us from the sun. This energy is called incoming solar radiation or insolation.
+
+%p
+  Of the insolation reaching the earth from the sun, only between 15% & 20% is captured by the atmosphere. The atmosphere and the earth’s surface reflect 40% of the insolation back into space. The remaining 60% is absorbed. The rocks, soil, and the water retain most of this energy. This energy is the re-radiated back into the atmosphere. This is what heats up the atmosphere. The atmosphere actually heats up from the bottom up. This is why when you are on the top of a mountain, even though you are closer to the Sun, the temperature is cold.
+
+%p
+  Two gases -- water vapor and carbon dioxide play the most important role in this function of keeping the earth warm.
+
+%h3 Temperature
+
+%p
+  Temperature does not measure the amount of heat energy the substance has. It is only a measure of the hotness or coldness of the substance. When something is hot its particles are moving more rapidly then when it is cool.
+
+%p
+  Temperature is measured in degrees
+
+%p
+  Fahrenheit degrees : used in weather forecasting
+
+.illustration
+  = image_tag "/images/freezing-point.png"
+
+%p
+  In the troposphere the atmosphere warms up from the ground upward. The higher up that you go the colder that it gets. The rate at which the temperature decreases vertically in the atmosphere is called the Normal Lapse Rate
+
+%p
+  If the atmosphere gets colder the higher you go,it is said to be Unstable; if it gets warmer it is said to be Stable
+
+%h3 How  Heat Travel
+
+%p Radiation:
+  %ul 
+    %li Heat traveling in waves coming from the Sun.
+    %li Same effect as heat coming from a fireplace.
+
+%p Conduction:
+  %ul 
+    %li Heat traveling from molecule to molecule. This is why the handle of a pot on the stove get hot even though it is not touching the fire.
+
+%p Convection:
+  %ul 
+    %li warm air rising ( this is due to the air expanding and becoming less dense then the surrounding air) and cold air sinking (becoming more more dense).
+
+%p
+  The atmosphere that  is not in direct contact with the surface of the  earth becomes heated only slightly by conduction. Instead, convection currents are established that circulate through the atmosphere.
+
+%p
+  Convection is a major way the atmosphere is heated -- especially in the Tropics.
+
+%p
+  Before we discuss the convection currents for transferring heat in the atmosphere, we must understand how a cloud is made. Adiabatic refers to temperature change by expansion or compression of air in the atmosphere.
+
+.illustration
+  = image_tag "/images/adiabatic-cooling.png"
+
+
+%p
+  This type of cooling occurs when air rises or is pushed upward from the earth’s surface. As the air rises, it expands. This is due to the atmospheric pressure decreasing with height. The expanding of the air causes the air to cool.
+
+%p
+  If the air is moist and the air is cooled sufficiently (below the dew-point), a cloud is formed. The dew point is the temperature at which the air becomes saturated. The warmer the air the more water vapor it can hold. So as the air rises, the temperature declines causing the air to become saturated (it can hold no more water vapor). The water vapor goes from a gas to droplets. A cloud is formed. It's like seeing your breath on a cold winter day.
+
+%p
+  The Hadley Cell shows us the atmospheric circulation in the tropics. As the Sun moves north or south of the equator, the Hadley Cell follows. If you look at the drawing below, keep in mind that it migrates north and south.
+
+%h4 Hadley Cell
+
+.illustration
+  = image_tag "/images/hadley-cell.png"
+
+%h3 ICZ : Intertropical Convergence Zone
+
+%p
+  Air rising at 10° latitude is warm & moist ; as it rises it cools (adiabaticly); clouds will form and it will rain: at this latitude is where we find the rain forest; air coming out of the top of the clouds reaches the top of the troposphere, it splits apart (diverges) ; some of it goes to the 30° latitude and the rest goes to the equator; at the equator the air cools converges (comes together) and descends; as it descends it is compressed and warms (this air is dry); the air going toward 30° latitude is cooled and sinks; as it sinks, it is compressed and warmed; when it strikes the Earth's surface, it diverges; the air going back toward the tropics is called the Trade Winds; air moving vertically is not a wind; sailing ships would get stuck at sea at the 30° latitude.
+
+%p
+  10° latitude is called the Doldrums
+%p
+  30° latitude is called the Horse Latitudes. At this latitude we find deserts from the hot dry air that is descending onto the surface of the Earth.
+%p
+  When the rises , it produces what is called a low pressure (L). Lows produce clouds and rain. When the air is falling, it produces what is called a high pressure (H). High pressure  areas have fair weather -- little or no clouds.
+
+.illustration
+  = image_tag "/images/divergence-convergence.png"
+
+%p
+  In a High (H) the air flows away from the High and turns Clockwise. In a Low (L) the air flows toward the Low and turns Counter Clockwise.
+
+%p
+  The sun migrates from 23 1/2° N to 23 1/2°S latitudes.
+
+%p The whole system follows the moving sun.
+
+%p
+  Between 23 1/2°N & 23 1/2°S the earth receives more radiant energy than in any other region. The earth’s atmosphere is not heated uniformly. This is due to the Earth being a sphere and the tilt of the earth.
+
+.illustration
+  = image_tag "/images/suns-rays.png"
+
+
+%p
+  The Earth's surface receives the maximum solar radiation when the sun-rays are perpendicular to the surface of the Earth. The closer your area is to 90 degrees the more radiation you receive. This is what happens in the summer time. In the winter time, the Sun's rays are at a low angle and rays are spread out giving us minimum amount of radiation.
+
+
+%p
+  If the earth did not rotate all wind would be north-south. But because the earth does rotate, all objects moving over the earth’s surface tend to veer off to the right(clockwise) in the northern hemisphere and to the left(counterclockwise). This is called the Coriolis Effect.