View of bead
chain with quarter shown for size comparison. Bead chain in action.
Apparatus Title: Standing Waves in a Hanging Beaded Chain
Abstract (40 - 50 words): Hands-on experiments that enable students to create standing waves with one open end are rather difficult. Ropes and strings are not feasible since they have such small linear densities. However, by using a length of bead chain, students can easily create standing waves that are open at only one end.
Support required for apparatus (ie. special needs in order to set up the equipment at the AAPT meeting): none
Approximate size: a handful
Does this apparatus require Electrical Power? no
Is this apparatus intended for use with an overhead projector? no
Will you be present to set up your apparatus? yes
When do you plan to set up your apparatus? Sunday, July 30 9-11 AM_____ 2-4:30 PM__X__ (Judging will be Sunday from 5 PM - 9 PM. Viewing will be Monday morning and afternoon, and Tuesday morning)
Equipment required to construct apparatus:
Total cost...........................................................................$ 1.65 or $0.40
Sketch of the apparatus:
View of bead
chain with quarter shown for size comparison. Bead chain in action.
A complete description of the apparatus is desirable, detailed enough that others can duplicate the apparatus. This description (anonymous) will be available to the judges of the apparatus. Samples of student reports (anonymous) may also help the judges to recognize the merits of this apparatus.
Description Hold a length of bead chain approximately one meter long by one end above the floor and move your hand periodically back and forth in the horizontal direction. Sometimes a slight rotational motion works best. If you move at the right frequency, the chain will resonate and develop a large amplitude oscillation even with very little hand movement. You can observe the properties of the resonance as well as determine the wavelength, frequency and wave speed. By moving your hand at different frequencies other resonances can be obtained and studied. NOTE: Due to the effects of gravity, the shape of the waveform will not be perfect.
Construction: Cut a length of bead chain approximately one meter long.
Apparatus Title: Right-Hand and Left-Hand Rules
Abstract (40 - 50 words): We have created a device that demonstrates rotational mirror symmetry. Working with right-hand and left-hand screws attached to opposite sides of a reflective surface, students determine the direction of travel of nuts on the screws and observe how the rotation of each nut is related to its mirror image.
Equipment required to construct apparatus:
All parts ordered from McMaster-Carr Supply Company
Total cost...........................................................................$ 4.00
Sketch of the apparatus:
.
A complete description of the apparatus is desirable, detailed enough that others can duplicate the apparatus. This description (anonymous) will be available to the judges of the apparatus. Samples of student reports (anonymous) may also help the judges to recognize the merits of this apparatus.
Description This device is a simple, hands-on demonstration of right hand and left hand rules. As you turn the nut on one side of the mirror you can observe its reflection and discover the actual nut on the other side of the mirror behaves as the reflection if you use the same hand motion. For example, if you turn the nut on the left away from you and it moves toward the mirror, turning the right nut away from you also moves it toward the mirror. This is a quick and easy exploration to familiarize students with left hand and right hand rules. It can be related to every-day experiences such as many water faucets with separate hot and cold controls.
Construction: Buff the aluminum sheet on a buffing wheel to create a good reflecting surface. Cut into 6 in by 6 in squares. Drill a ¼ in hole in the center of the plate. Cut threaded rods into 6 in lengths. Drill a ¼ in diameter pin cavity no more than 1 in deep in one end of each piece. On a lathe, chamfer undrilled end of each rod to round it. Or grind by hand. Using the roll pin, press together such that a right hand threaded rod piece is on one side of the plate and a left hand threaded rod piece is on the other side. Put nuts on respective rods.