9) Electrical Devices
a) AC-Devices
-
Flickering Neon Bulb on Wire
Shows AC current flickering on and off at 60 Hz as the
bulb is swung in a circle
Uses four AC solenoids to produce eddy currents in a
beer can causing it to spin.
-
Take-Apart Transformer with Iron Kernel
Shows the effect how the numbers of wire turns effect
a step up or step down transformer.
It can also be taken apart to show parts.
-
Mutual Induction Coils (Solenoids)
Shows Faraday’s law as current is passed through one
coil and current is induced in a
second coil. An iron core can be inserted to increase
the effect.
-
Self Inductance with Neon Bulb
A small neon bulb flashes when a battery is disconnected
from the inductor
causing the field to collapse
Shows energy stored in a capacitor that pops loudly
when discharged.
-
LR Circuit with Lamps & Coil
A light bulb and inductor are connected in series. A
second light bulb is connected in
parallel to them. When an iron core is inserted in the
inductor it changes the inductance and
the bulb in series with it dims, while the bulb in parallel
is unchanged.
-
LRC Resonance Circuit with red Light
An Inductor, resistor (red light bulb), and capacitor
are connected in series.
As an iron core changes the inductance the circuit is
tuned until the light bulb glows.
Shows a trace by audio frequency AC generator or an
oscilloscope.
The scope is a standard size 3"x4" screen so it is suited
for large classes, but can be seen using the multiledia system.
b) DC-Devices
-
Series Vs. Parallel Demonstration Box
Three light bulbs can be connected in series, in parallel,
or in combination for students to
see the results.
-
Earth Magnetic Field Generators
A very large coil of wires is hand-cranked in the earth’s
magnetic field to generate AC and
DC current.
A lecture hall sized example of a motor.
It uses electromagnets instead of permanent magnets.
An example of a simple DC motor using two bar magnets.
This is too small for large classes to easily see. Unless
you use the multimedia system.
-
Hand-Cranked Generator with Magnets
Example of power generation and transformation of energy.
-
DC Discharging Capacitor with Pasco Science Workshop
The decay of a capacitor discharging through a resistor
that can be displayed by the
Computer.
-
Ohm’s Law Resistor with Pasco Science Workshop
Shows a plot of voltage Vs current on the screen.
The instructor must slowly change the voltage and press
a key to measure the data.
This experiment will take about 10 min to perform and
I need 1 hour to get it ready.
-
Electro-Chemical Batteries
Simple take-apart electrolytic cell.
c) Meters
-
Digital Multimeter
-
Galvanometer (big) can be used as Ammeter or Voltmeter
-
Ballistic Galvanometer
-
Thompson Clock Face timer
d) Other
-
Jacobs Ladder (Climbing Spark)
The classic Frankenstein high voltage climbing spark
High voltage, high frequency coil used to excite gas
spectrum tubes.
Shows how high voltage, high frequency electricity can
be transmitted through air without
using wires.
A fluorescent tube held near the coil will glow nicely.
It also creates dramatic sparks and a lot of noise.
-
Alternating Copper / Steel Resistivity Wire
120 Volt AC current runs through a wire made of copper
and steel pieces.
The steel glows red hot while the copper remains cold.
-
Wooden Board for Demonstration of Electronic Drift
Shows the idea of electronic drift in a wire carrying
current using a marble bouncing down
A board of atoms (nails) or rolling down a superconductor
(No nails in its path). The idea of
Potential gradient can also be discussed based on relating
voltage potential to gravitational
Potential.
-
Solution Conduction Tester
A light bulb with two electrodes that are inserted in
a solution if the solution conducts
Electricity the light will glow.
A high-tech 5 volt 1 farad capacitor that is the size
of a half-dollar
-
Sample Capacitors, resistors, and Inductors
-
Millikan Oil Drop Experiment
Classical experiment of floating a charged oil drop
in an electric field to find the
fundamental unit of charge.
However this is unsuitable for large classes.