Cool Tools for Electricity & Magnetism
Workshop Overview
Buzz Putnam, Physics Teacher, Whitesboro, New York
Buzz is a 25 year veteran Physics and Nanotechnology teacher who has served as Whitesboro High School’s Science Department
Chair since 1997. Buzz also conducts Teaching Methods classes for science teachers at Utica College of Syracuse University.
Electrostatics
Concepts/Standards
Demonstrations
Materials/Apparatus
The excess or shortage of electrons
produces a net electric charge.
Turn the crank to move electrons onto the dome. Place the
discharge electrode near the dome and watch the spark!
The strength of an electric field depends
on the strength of the charge and the
distance from the charge.
Hold the discharge electrode at different positions and feel the
force on it grow as it gets closer to the dome (and as the dome
gains more charge).
Accurately determine positive or
negative static charge
Works with charged rods and electroscopes for determining the
final charge type after experimentation. Uses two LED’s to
indicate positive or negative charge.
Static Charge Indicator
Explore charging by friction, positive
and negative charge, and attraction and
repulsion.
Use the Friction Rods components to show charges: Rubber (-)
with fur (+) Glass (+) with silk (-) Rub the rubber rod with fur and
touch to negative charged electroscope. Discharge with finger.
Friction Rods, Fur, and Silk
Explore charging by contact
Just touch the top of the knob with a charged object, and the
needle will deflect away from post. Bigger charges cause more
deflection.
Explore Charge
These coated pith balls are for use with our Electroscope, or can
be use separately in other electrostatic experiments.
Coated Pith Balls
The excess or shortage of electrons
produces a net electric charge.
Turn on the levitation wand and toss one of the flying toys into
the air. Touch the wand to the toy once and shake it off. You now
have complete control over the flying toy.
Levitation Wand – a “mini
Van De Graaff” - toy
Hand Crank Van de Graaff
Generator
Demonstration Electroscope
The strength of an electric field depends
on the strength of the charge and the
distance.
Electric Current and Circuits
Concepts/Standards
Demonstrations
Direct Current always moves in
one direction. Alternating current
regularly reverses direction.
To model how energy can be transferred in both types of current, ask
students to rub their hands together to produce heat.
Ohm’s Law: Increasing the
voltage increases the current.
Keeping the same voltage and
increasing the resistance
decreases the current.
Use a hand crank generator to produce voltage through one bulb.
Turn faster to increase the voltage, and measure the current. Add a
bulb and produce the same voltage as before. Now what is the
current?
Materials/Apparatus
Hand Crank Generator
Store Electrical Energy
Show the relationship between
energy and wavelength
A series circuit has only one
path for current to follow. A
parallel circuit has more than
one path.
Attach a hand crank generator to the Capacitor.
Crank it, disconnect the capacitor and then connect it to a bulb.
Attach a hand crank generator to the Energy of a Photon apparatus.
Crank the generator slowly then increase the energy of the electrons by
increasing the voltage across the LEDs and you will see that the red LED
comes on at the lowest voltage, then the green, and finally the blue at the
highest voltage.
Five mini bulbs can be quickly arranged in series, parallel or complex
circuits, simply by adjusting the buss bars.
Capacitor
Energy of a Photon
Apparatus
Series/Parallel Bulb Board
Magnets and Magnetic Fields
Concepts/Standards
Demonstrations
The earth’s magnetic field is
parallel to the surface at the
equator and perpendicular at
the poles
Move the probe around the Magnetic Globe. Observe the field direction
and strength at different locations. Place Magnetic Chips on the globe for
a map of the earth’s field.
Magnetic fields are threedimensional.
Magnetic poles that are alike
repel one another, and
opposite magnetic poles
attract one another.
Magnetic fields are strongest
near the poles of a magnet.
Materials/Apparatus
Magnetic Globe
Magnaprobe
Let students observe the three-dimensional magnetic field with the.
Magnaprobe
Arrange clear compasses around a bar magnet (or other magnet) on the
overhead projector. Observe the positions of the needles.
Clear Compasses
Bar Magnet
Sprinkle iron filings or magnetic chips around a bar magnet to observe the
magnetic field lines. Lines close together indicate a stronger field.
Neodymium Magnet
Magnetic Chips
Iron Filings
Electromagnetism
Concepts/Standards
Demonstrations
Materials/Apparatus
Changing magnetic fields
create electric current. Moving
electric charges create a
magnetic field.
Drop a magnet through a copper tube. The moving magnet causes eddy
currents in the copper, which create an opposing magnetic field and slow
the magnet’s fall.
An electromagnet allows you
to turn a magnetic field on and
off.
Use a hand crank generator or a battery to power an electromagnet. How
much voltage is needed to hold up weights?
Electromagnet
Electric motors and electric
generators perform opposite
energy transformations.
Connect a hand crank generator to another. Use one as a generator and
watch the other turn as a motor. Investigate efficiency by counting the
times each handle turns.
Hand Crank Generator
Electron movement causing
the production of an ensuing
magnetic field
Using DC (Direct Current), electrons flow through a bulb’s filament in one
direction.
E&M Bulb Demo
Lenz’s Law Apparatus
Electromagnetic Flashlight
Neodymium Magnet
Using AC (Alternating Current), electrons flow through a bulb’s filament in
a two directions.
A magnetic field is produced when electrons flow through a conductor.
When magnets are placed near wires that carry electric current, a force is
exerted on the wire. When a wire carrying an electrical current is placed in
a magnetic field, each of the moving charges (electrons), which comprise
the current, experiences the Lorentz force, and together they can create a
macroscopic force on the wire.