Selected activities suggested for grades 3 - 6 at schools hosting a

Electricity and Magnetism Presentation.

Each activity is referenced to appropriate grade according to the Idaho State Board of Education.  A grade level in bold indicates a required topic, with non-bold levels indicating a recommended topic.  Relevant chapters in the Houghton Mifflin Science "Discovery Works" series are also referenced.  HM 4D2.1 refers to investigation 1 in chapter 2, unit D from the fourth grade text.

REPELLING STRINGS
Principle: Electric Charge, Static Electricity Grade: 5
HM 4D2.1
    Tie about 8 to 10 nylon strings to a rod.  Rub the rod with fur or wool, and you remove electrons from the fur and deposit them on the strings.  The strings will fly apart since they are all charged, and like charges repel.

CHARGE OF THE LIGHT BALLOONS
Principle: Electric Charge, Static Electricity Grade: 5
HM 4D2.1
    Rub two balloons through your hair and you transfer some electrons to them.  Suspend them by strings to show that they repel.  You can illustrate polarization by showing that a charged balloon will attract an uncharged balloon, but once they touch and transfer charge, they repel.  You can deflect a stream of water with a charged balloon because of the polarization of the water molecules.  You can also "levitate" light strings and joke about snake charming.  Sticking them to walls and ceilings is also fun.

SPIN THE BOARD
Principle: Electric Charge, Static Electricity Grade: 5
HM 4D2.1
    Charge up a balloon or a plastic cup, and bring it close (don't touch!) to a 1x4 balanced on a bowl bottom or a lens.  You can polarize the wood, and spin it one way, then the other, all without touching.

RUB THE TUBE
Principle: Electric Charge, Static Electricity Grades: 5, 6
HM 4D2.1, HM 5F1.1, HM 2B2
    Rub a fluorescent tube with wool or fur and it will glow.  Electrons are transferred to the glass from the fur, and some electrons dislodge and fly away from the other deposited electrons and excite atoms in the gas inside the tube.  As the atoms de-excite, they emit ultraviolet radiation which is absorbed by the phosphor coating on the inside of the tube, which causes the phosphor, and the tube, to glow.

ELECTROSCOPE
Principle: Electric Charge, Moving electrons  Grade: 5
HM 4D2.1
    You can construct a simple charge detector with a glass jar, aluminum foil, and some stiff wire.  Choose a quart glass jar with straight sides and a plastic lid.  Bend a small (~ 2 cm) sideways hook into a 25 cm piece of stiff wire (a stripped piece of coat hanger will work).  Stick the unbent end of the wire through a small hole drilled in the plastic lid, and fix the wire in a position so that the hook is in the middle of the jar.  A small glob of clay will work just fine for this.  Cut the unbent end of the wire so that only a  few inches of wire sticks up out of the lid.  Once you have the wire where you want it, fix it in place and seal the hole with wax dripped from a candle.  Hang two thin (~ 3 to 5 mm) aluminum foil strips from the hook so that they touch.  Heat the jar so that it is dry and warm inside, then quickly seal the jar.  Top the protruding wire with a ball of crumpled aluminum foil, and you are done!  Bring something charged close to the ball, and the aluminum strips repel each other.  This is because the wire and foil polarize when something charged is brought near.  The opposite charge is attracted to the ball on top, and the like charge is repelled down into the strips, which then repel each other.  Remove the charged object, and the strips return to normal.  If you touch the charged object to the ball, you transfer charge, and the strips will remain deflected.  Knowing the charge of one object, you can determine the charge of other objects with this device.

CONDUCTORS?
Principle: Electric Charge, Moving electrons Grade: 5
HM 4D2.2, HM 5C1.1
    Make two 1 cm wide, 10 cm long aluminum foil wires by folding strips of foil 3 or 4 times.  Tape one end of each to opposite ends of a D battery.  Connect the other end of one wire to the side of a flashlight bulb with a clothespin.  Tap the bottom of the bulb on the other wire and the bulb will light.  You can have your students check various objects to see if they conduct by placing the objects between the loose wire and the flashlight bulb.

FOIL JOULE HEATING
Principle: Electric Charge, Moving electrons  Grade: 5
HM 4D2.1, HM 4D3.2, HM 3C2.2
    You can have your students take a thin aluminum foil wire and connect it directly across a AA battery.  The foil will warm quickly.  Moving electrons scatter off of imperfections and impurities, transferring energy to the foil in the form of heat.  This is called Joule heating.  You can use this to illustrate how a stove or electric heater works.  

POCKET CURRENT METER
Principle: Moving electrons, Magnetism Grade: 5
HM 4D3.1, HM 4D3.2
    Wrap a long (1 m) aluminum foil wire, or any insulated wire with exposed ends, several times about a compass.   Connect the ends of the wire across a battery and the compass will deflect. This is because moving charges create a magnetic field.  In fact, all magnetic fields can be traced back to the motion of charges.

A CURRENT IS A MAGNET, A MAGNET IS A CURRENT
Principle: Moving electrons, Magnetism  Grade: 5
HM 4D3.1, HM 4D3.2
    Poke a hole in the middle of a piece of poster board and run a straight 60 cm large gauge solid wire (not twisted) through the hole.  Support the wire and poster board so that the board is horizontal and at the mid point of the wire, with the wire perpendicular to the board.  Place several small compasses on the poster board in a circle about the wire.  Connect the wire to a 12 V lantern battery with allegator clip wires, and watch the magnets!  Moving charges create a magnetic field in the form of circular loops perpendicular to the direction of their motion.  For large classes, it might be more convenient to set the wire horizontal pointed towards the class, and trace the magnetic field loops with a dip compass.   

ELECTROMAGNET
Principle: Electric Moving electrons, Magnetism Grade: 5
HM 4D3.2
    Magnetic fields can be much stronger in materials than they are in air.  Wrap an aluminum foil wire several times about a nail, and connect the wire to a D battery, and you have an electromagnet!  With the wire looped, the "loops" of magnetic field produced by the moving charges all add up in the center of the wire loop, creating a much stronger field than what a single wire could produce.

MAKE A MAGNET, BREAK A MAGNET
Principle: Magnetism Grade: 5
HM 4D1.1
    Magnetize a hacksaw blade by rubbing it in one direction with a strong permanent magnet using firm slow strokes, with the orientation of the permanent magnet the same at all times.  Twenty to thirty strokes should suffice.  Use iron or metal filings to show the location of the magnetic poles at the ends of the blade.  Also demonstrate that the filings do not stick to the blade in the middle.  Break the hacksaw blade in half, and now you have two magnets, each with a pole at each end!  You can keep this up until you are bored, and you will never get just one pole.

TOTALLY TUBULAR MAGNETS
Principle: Magnetism Grade: 5
HM 4D3.1, HM 4D3.2
    Magnetic fields affect moving charges, but not stationary ones.  Similarly, a moving magnet (or a simply a changing magnetic field) can affect a stationary charge.  Only relative motion is important (this is what got Einstein going).   In other words, a changing magnetic field creates an electric field, and a changing electric field creates a magnetic field.  As a general rule, the electric field created by a changing magnetic field will be oriented so that it could cause nearby charges to move in a manner that would create a second magnetic field directed to oppose the change in the original magnetic field.  Electric currents created from this effect are called "eddy currents" due the circular motion of the charges.  In other words, a moving magnet will create a "virtual magnet" if it moves near a conductor.  The virtual magnet will be oriented to slow the moving magnet down.  To illustrate this, drop a strong magnet down a copper tube, and show that it takes a lot longer to drop out the end than anything else of similar size and weight.  You can also move a strong magnet past a non-magnetic conductor (copper is best) and feel the resistance.

SIMPLE BATTERY
Principle: Moving electrons, Chemical reaction Grades: 5, 6
HM 4D3.1
    Clean or brighten an iron washer and a copper penny.  Soak a 1 inch square piece of heavy blotter paper or folded paper towel  in vinegar.  Press the soaked paper between the washer and the penny to form a simple battery.  Measure the current with wires connected to the pocket current meter, with one wire pressed against the washer and the other pressed to the penny.  This battery will not be strong enough to light a flashlight bulb.  The vinegar induces a chemical reaction between the copper and the iron.  Charged "ions" will flow through the vinegar from the copper to the iron.  The reaction continues as long as one piece of metal can get rid of its excess electrons through the wires to the other piece of metal to balance the natural flow of charge through the blotter paper.