Weather             

Charlene Clark                 Fulton Elementary School
                               5300 S. Hermitage Avenue
                               Chicago IL 60609
                               (773) 535-9000

Objectives:

This lesson is designed for Grade 5 science.
Each student will be able to:
     Distinguish among evaporation, condensation, and precipitation phases of 
     the water cycle.
     
Materials Needed:

 Activity 1.  two equal pieces of sponge, string, wire coat hanger, hair dryer, 
              ring stand, tap water in container to wet sponge
 Activity 2.  hot plate, pan of water with lid, mirror
 Activity 3.  chalk dust, hammer, nail, 2 lids (one that fits the jar, and one 
              that's extra large for the jar), medium-sized jelly or pickle jar,
              very hot tap water, timer, 2 ice cubes
 Activity 4.  container filled with sod and saturated with water, plastic wrap, 
              chicken wire, heat lamp (optional)
                            
Strategy:
             
  Introduction:
      Ask students to think about the word "cycle".  Bring out the concept that 
  a cycle is round.  Then introduce the subject of the water cycle, which will 
  be developed further, when an understanding of evaporation, condensation, and 
  precipitation, are understood.         
   
  1.  Evaporation          
      Begin by asking questions about evaporation.  Allow students to give 
examples of evaporation and list them on paper or the board.  Demonstrate 
evaporation with Activity 1.  Tie equal lengths of string around equal pieces of  
sponge.  Wet each piece of sponge with equal amounts of water.  Attach the free 
end of the string to a coat hanger.  Balance the hook of a coat hanger on a ring 
stand.  Use a hair dryer to evaporate the water from one sponge piece.  When one 
sponge is dry (water is evaporated) the coat hanger should balance unevenly 
showing that water has weight and has evaporated from the sponge that is now 
dry.  Develop a definition for evaporation, which is water that changes from a 
liquid to a gas called water vapor which cannot be seen.  Rising warm air 
carries the invisible moisture high up in the sky. 

  2.  Condensation
      The invisible water vapor gathers together as it cools and condenses to 
form a cloud.  The droplets stick together with the help of dust particles in 
the air.  Lead students to discover that evaporation and condensation are 
opposite occurances.  Discuss various ways water vapor condenses.  With Activity 
2, show condensation of water by heating a pan of water over a hot plate and 
holding a mirror or jar lid over the steam until the vapor condenses. 
 
  3.  Precipitation
      Eventually the collection of water droplets that form a cloud gather and 
get larger and heavier.  When they get too large and too heavy to be held up in 
the air, they fall to the ground as a form of precipitation.  Precipitation is 
water in any form falling from the clouds.  It includes rain, drizzle, hail, 
sleet, and snow.  Warmer air causes droplets to fall as rain.  As the air turns 
colder, the water freezes and precipitation turns to sleet or snow.  Hail is 
freezing rain that is bounced up and down by wind currents adding layers of ice 
to form hailstones.  The inside of hailstones is similar to the rings of a cut 
tree trunk.  With Activity 3, show a demonstration for precipitation.  Fill a 
jar 100% with hot tap water.  Cover it tightly with the lid and let it stand 2 
minutes.  Remove the lid, pour out 90% of the water.  Place the large lid, with 
holes punctured in it, on top of the jar.  Cover the lid with ice cubes and let 
it stand 3 minutes.  Remove the lid and cubes.  Sprinkle chalk dust into the 
jar.  Cover the jar with the tightly fitting lid.  After 2 minutes observe the 
inside of the jar.  A cloud has formed along with precipitation falling.  By 
heating and cooling the water in the jar, it caused droplets of water to form. 
This demonstration shows that clouds are collections of tiny water droplets that 
form around particles of dust, dirt or salt.  Without tiny particles in the air, 
we would not have clouds - or rain.  
                        
      What happens?  Water is constantly recycled over and over again, since the 
beginning of time.  People and animals and plants use the same water over and 
over again.  Water in the ground, in lakes, rivers, oceans, puddles, etc. is 
used, evaporated in the air, condenses and falls as precipitation and is used 
over and over again and again.  At least 3/4  of our planet is water.  
Everything we see and use is mainly made up of water.  Even our bodies are 
mostly made up of water.     
      Show a demonstration of the water cycle with Activity 4.  Fill an aluminum 
pie tin with sod and saturate it with water.  Make a tent cover of chicken wire 
covered with the plastic wrap.  Place it in the sunlight or use heat lamp.  
After a time water droplets should appear.  Similar to a terrarium.   

Performance Assessment:

     Ongoing assessment throughout activities based on the student's 
participation and responses. 

References:

     Bramwell, Martyn. Weather. New York: Franklin Watts, 1987.
     Purvis, George and Anne. Weather and Climate. New York: The Bookwright 
Press, 1984.
     VanCleave, Janice. Chemistry for Every Kid. New York: John Wiley and Sons, 
Inc., 1989.