Electrostatics

Alyce Glauner                   Grant Community Academy
                                145 S. Campbell Ave.
                                Chicago IL 60612
                                (773) 534-7275

Objectives:

     The main objective of the Mini-teach is to show Primary students that      
there is electricity in all matter. 

Materials Needed:

    Van DeGraff Generator             5 Balloons
    Rabbit's Fur                      Glass Rod 12-18 inches long
    Plastic Rod 12-18 inches long     Piece of String 15cm long
    Tape                              3 Pieces of String 35cm long
    Small Paper Scraps                Salt and Pepper
    Puffed Rice                       Mashed Potato Flakes
    Electroscope      
    Small stream of running water (if available)
    Enough for the class or group-pop cans, 1 in x 1/2 in, aluminum foil strips
    combs, foam plates, foam cups, pie plates.

Strategy:

    Using the Van DeGraff generator place the pie pans face down on top.  Put 
the generator on have students stand back and watch the plates sail off.  If you 
have older students, they can form a chain to see how far out the charge will 
travel.  Always discharge the generator with a stick when you turn it off.  The 
students can also try one at a time to place their hand on the generator, while 
they stand on a milk-crate to insulate them from the ground.  See what happens 
to their hair. 
    After the demonstration, the students go to stations.  Your options to set 
this up: 
    
    1) Balloons-Tape one end of 15cm string to a table top.  Charge a balloon by 
rubbing it with the fur.  Hold the balloon over the thread, don't touch, the 
thread should move towards the balloon.  Tie a 35cm string to one balloon, hang 
it on something freely, tie the other string around another balloon, and hang it 
about 5 cm. away from the first.  What happens?  Charge one of the balloons, 
what happens?  Charge the other balloon, what happens?  The first time they 
should attract, the second time they should repel.  Charge a balloon and see if 
you can get it to attract to the wall.  Tie the last 35cm string around a 
balloon and hang it up or tape it to a table.  Charge the balloon and place your 
hand close to the balloon, don't touch, it should follow your hand. 
  
    2) Combs-Comb your hair very hard.  Place the comb near one of the above 
items.  The static electricity will make the item attracted to the comb.  Try 
with a number of different items.  Come up with your own ideas.  Comb your hair 
again and place the comb near the running water.  The stream of water will 
either repel or attract (the water really moves). 
    
    3) Electroscopes-Rub fur on the bottom of the foam plate, place a pie pan on 
to the foam plate.  Lightly touch the pan to charge it.  Bring the charged pan 
over to the Electroscope.  The leaves of foil will repel because of like 
charges.   
    
    4) Make Electroscopes and Electrophorous-Glue a foam cup on top of a pie 
pan, as a handle.  Use two foam plates, turned upside-down, to rub the pan on to 
charge it.  Tape a pop can to the top of a foam cup.  Take the foil strip and 
loop it loosely over the tab of the can. 

Performance Assessment:

     The assessment would probably be teacher observation.  Did the student
follow directions?  Did the student participate in stations?  To what extent was
his participation?  You could also have them record their observations and 
results in their journals.  A rubric would be easy to make for this exercise
using:  
    4=followed directions, used all stations provided, recorded all
      information requested.  
    3=followed directions, used most of the stations provided, recorded most of 
      the information requested.  
    2=followed most of the directions, used some stations, recorded some 
      information.  
    1=followed some directions, used few stations, recorded little information.  
    0=nothing done.