How Smart Are You About Electricity, Batteries And Conductors?

Lorraine Epps                  Douglass Math and Science Academy
                               543 N. Waller Street
                               Chicago IL 60644
                               (312) 543-6176

Objectives:

Students will:                           
  
- identify a battery and how it works.
- identify how a flashlight works. 
- understand the relationship between a battery and electrons.
- conduct a test to determine what materials are the best conductors.
     
  (This unit will take two to three weeks)       Grades 3-8

Materials:
   
Overhead projector and transparencies of all activities.
Activity 1.  pennies and dimes or aluminum foil, paper towels, water, salt, 
vinegar, lemon juice and an ammeter
Activity 2.  signs and small pieces of colored paper
Activity 3.  D-batteries, 1.5 V bulb, masking tape, wire, aluminum foil and
materials for decorating
Activity 4.  batteries (1.5 or 6 V), bulb (1.5 or 6 V), wood(2 by 6 ins.),
4 feet of insulated copper wire (2 feet for each side), two pencils with 
eraser tips, two clean head thumbtacks, and a number of objects to be tested  

Strategy:
   
Activity 1:            MAKE A BATTERY

Students will identify a battery and how it works.                  
Teacher will demonstrate how to make a "VOLTAIC PILE" (named after the inventor  
of the battery). 
Students will fold some paper towels about 1 inch square, soak them in one of 
the solutions with a 1.5 glass of water, by placing a dime, foil and penny on 
each side of the moistened towel, making a single cell, then connect your cell 
with wire on both ends of coins to ammeter.  Students will notice needle moving 
thus indicating that there is a flow of current.
Next, students will make more cells piles, connecting them together to see how 
great the voltage will become.  Students will record data as they add cells and 
take piles apart when finished so coins will not corrode. 

Activity 2:            GAME:  PATH OF ELECTRONS

Students will stand in a circle to show how electrons work in a battery called a 
circuit, (a drawing of a battery showing the path electrons flow).  At the top 
of the circle, one student will be marked negative (-), another will be the 
positive (+) end of the battery.  A third student will be the switch, another 
one the bulb, and the rest of the students will be the conductors.  They will 
have pieces of paper marked electrons.  Students will start passing the pieces 
of paper around as shown on drawing.  When the switch goes out of the circle, 
the light will go out.  (This will show the current of electrons flow around and 
around the circuit as long as the switch is on.  When the switch goes off, the 
current stop and the flow of electrons will stop and the light bulb will stop 
glowing.) 
                                                  
Activity 3:            MAKING A FLASHLIGHT

Students will make a flashlight to see the relationship between a battery and 
conductors.  Each students will be given materials needed to make a flashlight. 
First, cut tubes length-wise to fit batteries, then cut a piece of wire (strip 
bare the insulation), the wire should also be cut longer than the tubes.  Make 
sure wire is connected to the battery and the bulb.  Then use the aluminum foil 
as a conductor.  If all connections are correct, current is complete and the 
bulb will light up.  Students can decorate flashlight any way they choose. 

Activity 4:            CONDUCTIVITY TESTING

Students will construct a conductivity tester.  They will learn how to connect 
one of the terminals of the battery to the bulb assembly (a flashlight bulb in a 
socket mounted on  a piece of wood).  One wire from the battery terminal and the 
other wire to the bulb assembly are to be connected to become the test probes.    
Wrap the wire around two clean-head thumbtacks (six times).  Push them firmly 
into the erasers of the two pencils.  When you apply testing probes to each 
object, the bulb will light up to show you that all metal objects are conductors 
of electricity.  The bulb will not light up if objects are not good conductors. 
Students will make a chart to list and show good, poor and non conducting 
objects.  Then list each object on different color pie-shaped papers.  Mount 
them on a wheel to visualize the percentage for each category. 
 
References:
    
Graf, Rudolf F., Safe and Simple Electrical Experiment
Strongin, Herb, Science On A Shoestring
Introduction to Physical Science:  Addison-Wesley (1988).