Lecture Demos

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Diffraction Gratings

Diffraction Gratings

These items are diffraction gratings of different kinds that can be used to view the spectral patterns of light sources or to view the patterns of light diffraction

PIRA Code(s): 
6D20.10
Set up time: 
none
Physics and Science Concepts: 
Optics, Light Spectrum
Operation: 
For best results, observe the sun, moon, or fluorescent lights through the films.
Safety: 
Keep fingerprints off film.

Assortment of Glass Prisms

Assortment of Glass Prisms

This is an assortment of prisms. When light enters at an angle to the face of a prism, it is refracted. Since the index of refraction depends on the wavelength, the light is refracted at different angles and therefore it is dispersed into a spectrum of colors.

PIRA Code(s): 
6A40.99
Set up time: 
none
Physics and Science Concepts: 
Optics, Refraction
Operation: 
Shine a focused beam of light at one of the facets of the prism. Light is refracted and split into its constituent wavelengths (i.e. Colors of the rainbow). These can be used with various other optical experiments.
Safety: 
Edges and corners may be sharp

Concave and Convex Mirrors

Concave and Convex Mirrors

This is a set of concave, convex, and flat mirrors.

PIRA Code(s): 
6A20.45
Set up time: 
none
Physics and Science Concepts: 
Geometrical Optics, Reflection
Operation: 
Use the different types of mirrors to compare reflection.
Safety: 
Do not shine bright light into mirror.

Meissner Effect

Meissner Effect

This demonstrates levitation of a magnet above a high-temperature superconductor.

PIRA Code(s): 
5G50.50
Set up time: 
2 minutes
Physics and Science Concepts: 
Superconductivity, Magnetic Materials
Operation: 
A superconductor disc is placed in a styrofoam dish and liquid nitrogen is added to the dish. A small magnet is placed on top and within a few seconds it begins to levitate.
Safety: 
Liquid Nitrogen can be obtained from the machine shop.

Fluorescent Lamp Circuit

Fluorescent Lamp Circuit

Fluorescent lamp circuit mounted on a board can be used manually or automatically.

PIRA Code(s): 
5L20.14
Set up time: 
1 minute
Physics and Science Concepts: 
AC Circuits
Operation: 
Plug in the circuit. Flip the switch that says line and then put the lever to the automatic side for the whole lamp to light up. Flip the line switch again and move the lever to the middle. Put the line switch on again and move the lever to the manual side. This will heat up the filament. Then move the lever a little away from the manual side for the entire light to be lit.
Safety: 
None

Jumping Ring

 Jumping Ring

This experiment uses a coil of wire with a solid iron core inside the coil. When the switch is closed and AC current flows through the coil, the continuously changing magnetic field create eddy currents inside of metal rings place over the iron core. The rings will jump different heights depending on their thickness. Sparks can be created with a copper coil, while a light bulb attached to a coil will shine. Resistive heating can be demonstrated by holding the full rings down and feeling them heat up.

PIRA Code(s): 
5K20.30
Set up time: 
2 minutes
Physics and Science Concepts: 
Lenz law, Electromagnetic Induction, Eddy Currents
Operation: 
Set up the apparatus so that the silver pole sticks above the platform a few inches. Place a full ring around the tube and turn the apparatus on. This will make the ring jump into the air. Turn off the machine then, place the split ring around the pole, turn on the machine and this will not do anything. Resistive heating can be demonstrated by holding the full rings down and feeling them heat up. Next, turn off the machine, place the copper coil around the pole and press down on the copper rod sticking off the coil to create sparks. Also, place the light bulb circuit ring against the flat top part of the pole and watch it light up.
Safety: 
Do not place apparatus directly under a light. Do not stand above machine when the rings jump. Do not hold the full ring down too long, you may get burned.

Eddy Current Pendulum

Eddy Current Pendulum

A pendulum swings between the poles of a large permanent magnet. The full copper sheet swings a few times then stops in between the magnet. The comb copper sheet is unaffected by the magnetic and swing freely because the gaps in this sheet do not allow significant eddy currents to flow.

PIRA Code(s): 
5K20.10
Set up time: 
5 minutes
Physics and Science Concepts: 
Electromagnetic Induction, Eddy Currents
Operation: 
Set up the pole with the right angle clamp and pendulum. Place the permanent magnet so that the copper sheet is in between the two magnet sides. Swing the full copper sheet swing through the magnet. Watch as it damps out quickly. The, flip the pendulum so that the copper comb side is swinging through the magnet. Watch how it swings as if the magnet is not even there.
Safety: 
Stand to the side of the pendulum as it swings, not directly in the path.

Induction Coil, Magnet, Galvanometer

Induction Coil, Magnet, Galvanometer

A galvanometer is activated by placing a magnet near an induction coil and rotating the induction coil.

PIRA Code(s): 
5K10.20
Set up time: 
1 minute
Physics and Science Concepts: 
Electromagnetic Induction, Electricity and Magnetism
Operation: 
Hook the leads from the galvanometer to the induction coil. Place a magnet in front of the coil. Turn the crank and the needle on the galvanometer should move. The connection between the galvanometer and the loop changes polarity every half turn.
Safety: 
Magnet is extremely strong so do not place metal objects near it.

CRT with a Magnet

CRT with a Magnet

A bar magnet can deflect the electron beam in a cathode ray tube (CRT) according to the right-hand rule. This is due to the force a magnetic field has on a moving charge.

PIRA Code(s): 
5H30.10
Set up time: 
2 minutes
Physics and Science Concepts: 
Magnetic Fields and Forces
Operation: 
Plug in the cathode ray tube. Deflect the beam of the CRT by holding a permanent magnet near the edge of the tube. If the beam disappears, you are holding the magnet too close. Also, you can deflect the beam by attaching a battery to the binding posts and adjusting the variable control knob.
Safety: 
None

Magnet and Iron Filings

Magnet and Iron Filings

A bar magnet is positioned beneath a piece of paper on an overhead projector. Iron filings sprinkled on the paper will show the magnetic field. The overhead projector displays the image.

PIRA Code(s): 
5H10.30
Set up time: 
3 minutes
Physics and Science Concepts: 
Magnetic Fields and Forces
Operation: 
Place the magnet under the piece of paper and on the overhead. Sprinkle iron filings over the magnet and the filings should align with the magnetic field.
Safety: 
An overhead can be obtained from demonstration 9A36.10.