Rods ranging in size from 10 cm to 40 cm are attached to a steel rod that flexes to produce wave motion down its length. The machine can show standing waves, reflection, damping, resonance, impedence matching, reflection at the boundary between two media, and superposition. The end of the rods are painted to make the wave motion visible when illuminated with UV light. this machine can also be motor driven.
1. Bell Labs wave machine (3 sections)
2. Metal fasteners
3. Up to 5 sets of blacklights
1. Balance machine carefully on stand (set up stands and drop machine into place)
2. Remove wave machine "holders" by unfastening wing nuts
3. Attach metal fasteners if intended demonstration is impedance matching
4. Use black lights to illuminate the green painted side
5. Different phenomena may be demonstrated including: damping, reflections, standing waves, resonance, impedance matching, and superposition.
Damping: Perturb the rods on one wave machine and observe the dissipation of the pulse that is created.
Reflections: Perturb one end of a wave machine and observe how the wave is reflected at the opposite end. If the end is left open, the reflected wave will have "positive" amplitude. If the end is held still, the reflected wave will be inverted.
Standing Waves/Resonance (not recommended due to fragility): Shake one end of the wave machine at a specific frequency to generate standing waves of different resonances.
Impedance Matching: Attach all segment of the wave machine together with metal fasteners. The point at which the segments are connected should have the same sized rods on either side. A pulsed wave will travel through all segments without reflection at the connection points.
Superposition: Perturb opposite ends of one segment at the same time and observe how the waves appear when they pass each other.