Physics 123 Weeks 6 & 7 (Magnetic Fields and Forces)
**WARNING** Any demos that require a supply can "short out" the power supply easily. Please be aware of your circuits, and include a contact key switch or resistor block when necessary.
Magnets and the Magnetic Field
Assortment of Magnets
We have many different magnets in our demo room. Here are just a few of the ones you can find in the cabinets. If you want to use the iron cylinder to discuss the difference between a piece of metal and a magnet, please remember to NOT store the metal in contact with a magnet.
Seeing Magnetic Field Lines
Using an array of compasses, needles, and iron filings, you can show your students magnetic field lines surrounding different types of magnets.
Dip Needle
First, align the needle horizontally as you would a normal compass. Then, rotate the disc so that the needle is perpendicular to the ground. The angle measured from vertical is the angle at which the Earth's magnetic field comes out of the surface.
The Magnetic Force
The Magnetic Force
Using bar magnets or magnetized needles on pivots, a magnetic Newton's Cradle, or even some donut magnets on a cylinder, you can show your students the basics behind the magnetic force!
The Oersted Effect
**WARNING** Please include a resistor block, or contact key switch in series with the PSU
Use an array of compasses placed around various wires to show your students the Oersted effect.
Electron Deflection
** WARNING** X-Ray source. Limit exposure
Use the hand held high frequency generator to create an electron beam in this cathode ray tube. Cause the beam to deflect by bringing a strong magnet nearby.
Wire Deflection
**WARNING** Creates a short, do not hold switch down for long.
When you press the switch, current travels through the long piece of aluminum foil. Since it is suspended in a magnetic field, it will deflect up or down depending on polarity.
Vibrating Lights
When a strong magnet is held near the glass of a carbon bulb, the filament will begin to oscillate as the alternating current applies an alternating force on the filament.
Forces on Current Carrying Wires
Two conductors are allowed to swivel when current passes through them. Depending on how you configure the device you can show students how wires will attract or repel from each other when they are live.