Brief Overview:
Students are interested in clouds and the overall part that clouds play in determining atmospheric conditions .   This lesson may lead to an understanding of what clouds are made of, how they form and the complex role that clouds  play in global climate change.   This activity may be used as a motivational lab or may be modified for demonstration purposes.   To ensure inquiry, students need to develop their own hypothesis and draw their own conclusions.
 
Notes for the Teacher Only:
For background information on clouds and good links to other cloud sites, see Cloud Background.

Materials and Equipment Needs:
Group students in small groups (3-4 each).  Issue the following items to each group.
goggles (1 per person)
plastic soda bottle /with tubing fitted caps (see special instructions on this page)
25 ml graduated cylinder (per group)
inflating pump
liquid crystal thermometer
tape
matches
water
 
Activity Procedures:
Remember this activity may be used as a motivational lab or may be modified for demonstration purposes.  If used as a lab, distribute student page to groups.
Carefully tape the temperature strip to the inside of the bottle.
Add 25-30 ml room temperature water to the bottle.
Place the cap outfit tightly on the bottle.
Read and record the temperature.
Attach the pump tip to the cap tubing.
Pump the bottle and read the temperature again. Record temperature.
Release the pressure and observe what happens to the temperature. Record.
Record all observations

How to make the cap used in Cloud Activity
Materials:
cap from a plastic soda bottle that has an easily removable inner liner
awl or other pointed object
1/4 inch drill bit
pencil or chop stick
about 2 inches of 1/4 inch (OD) nylon tubing (available from hardware store)
about l 1/2 inches of 1/4 inch inner tubing  (available from hardware store)
electrical tape

Procedures:
1.  Using the awl bore a starter hole through the center of the cap including the liner from the top of the cap.
2.  With the drill bit expand and clean out the hole from the top of the cap (use a cloth to turn the drill bit)
3.  Use the pencil or chop stick to widen the hole in the liner without cutting or tearing it. Remove the stick.
4.  Insert the nylon tubing into the liner in the same direction as above so that the inserted end extends out of the
        bottom of the liner about as far as the electrical tape is wide.
5.  Wrap the tubing and the part of the liner that overlaps it with a couple of tight round of electrical tape.
6.  Insert the untaped end of the nylon tube into the bottom of the cap and through the hole.  Orient the liner so that it is
        centered.
7.  Push on the bottom of the tubing and tightly wrap the tube right at the top of the cap with a couple of  turns of electrical
        tape.
8.  Place the piece of flexible tubing over the top end of the nylon tubing and your cap is ready for use.

        ** Note:   Gathering materials to construct the bottle top can be challenging to begin with, but once they are made, they may
                         be used repeatedly.

Extensions:       Vary the size of the container
                        Color the water
                        Increase the amount of water
                      * Allow students to choose other variables as well

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The Woodrow Wilson National Fellowship Foundation webmaster@woodrow.org
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