Water Cycle - Atmosphere (2)
Pre Lab 

   
OBJECTIVES:
  • Distinguishing air.
  • Comparing the layers of the atmosphere.
VOCABULARY:
  • air
  • atmosphere
MATERIALS:

Students demonstrate that  air can move items.

 

BACKGROUND:

Air weighs over 5 quadrillion tons, but yet we can't see, smell, or feel it.  Even so, air is a powerful force on Earth.  Most organisms cannot live without air.  Astronauts that go into space must take tanks of air with them.  Divers that go under the ocean, must take air with them.  If we climb a mountain that is too high, the air becomes less and less breathable.  The downward force exerted by overlying air causes greater pressure at the bottom of atmosphere.  Air molecules are actually “squeezed” by the weight of the air above. 

The atmosphere is layered between the surface of the Earth and outer space.  The layer we live on is called the troposphere.  The air moves up and down, the winds blow, moisture builds up, and different types of weather are created.  The layer above the troposphere is called the stratosphere which is 32 kilometers thick (20 miles).   The upper part of the stratosphere contains a higher percentage of ozone. This layer of ozone is a form of oxygen that protects the surface of the Earth from the Sun's ultraviolet rays.    

The next layer is called the mesosphere which is much colder than the stratosphere.  The thermosphere is the next very thick layer which is divided into the ionosphere and exosphere.  Radio waves from Earth hit the ionosphere and bounce back to Earth   This makes it possible for you to hear a radio station.  Beyond the exosphere lies outer space. 

Each of these layers acts as a unit because they have similar characteristics including chemical composition, temperature, and pressure. 

PROCEDURE:
  1. Give students worksheet and point out the information discussed in background.  Show students the wave machine and illustrate how the clear liquid (kerosene) does not mix with the colored liquid (oil).  This is similar to how the layers of the atmosphere interact.
      
  2. If you want the students to prove that air is everywhere but is invisible, have a student put a straw into a glass of water and blow into it.  They will see bubbles form, rise to the surface and pop.  The student has caused air to move in the water. 

Other demonstrations to show students:

  1. Bernoulli’s pipe  - Blow in one side and the ball will be suspended if the ball is placed correctly over the stream of air.  You can also be more dramatic by using a ping pong ball with a hair dryer blowing air underneath it.   If placed in the correction position it will seem as the ball is suspended in air.
  2. Tour of Bubbles - When you turn the long cylinder upside down, a small bubble will form slowly and rise, pushing the heavy liquid away from its path.
  3. Puddle Jumper - When you twirl the base away from your body and let go, the design of the puddle jumper acts like a helicopter and uses the air to move.
  4. You can also prove that air is all around by using a balloon and just blow into it.  The balloon changes shape because of the air.   
  1. Use the worksheet for the students to color the different “spheres” of the atmosphere.  The troposphere ends around 17,600 meters, the stratosphere ends around 48,000 meters, the mesosphere ends around 88,000 meters, and the ionsphere goes up to 200,000 meters.  Notice that the exosphere does not fit into the scale of this diagram. 
      
  2. You may also tell students that flying through the troposphere can be “bumpy” if the weather is active.  Modern jet airplanes avoid this problem by going into the stratosphere where the air is calm. 

[Dictionary]
 [Back to Water Cycle Grid]
  [Back to Atmosphere (2)]