Show wave propagation, destructive/constructive interference, Doppler shift, 1 and 2 slit diffraction
Directions: 1. Support the plexiglass tank on the edges of two tables. ensuring that the tank is level. 2. Add ~12L of water to the tank and line the walls of the tank with sponges (to diminish wave reflections) 3. Place a light bulb to hang above the center of the tank. 4. Lay the large sheet of white, corrugated material under the tank. 5. Connect the mechanical relay circuit to the function generator and variable power supply using the labeled, color co-ordinated wires 6. IMPORTANT: Set the power supply to ~20V and set the current to almost zero before connecting it to the circuit or else you will fry the relay, if the relay doesn't move, increase the voltage ONLY and do no exceed 24V 7. Using low-frequency square waves, the relay's mechanical impulses generate circular waves. The resulting waves are then projected as shadows onto the floor.
If showing single wave propagation, attach only one rod to the relay. If displaying two in-phase circular waves, attach both rods.
To create a wave front, attach the metal bar to the relay. Use wooden blocks to construct either a single or double slit scenario (The metal bar is flimsy and absolutely sucks, I did not make it but it would be worthwhile making a new one)
Doppler shift can be displayed by attaching a single rod to the relay and dragging the relay at constant velocity across the tank.
A video camera can also be connected to projectors in large lecture halls if this demo is intended for a large audience.
Useful Links: These YouTube videos detail each of the above scenarios.
Locations: - Plexiglass tank and large sheet of white, corrugated material –> near elevator against the wall. - Wave generator (Mechanical relay circuit) –> Cardboard box, blue closet, right side - Function Generator –> Search “Function Generator (older version)” on the catalog - Power Supply –> Search “50W Power Supply” on the catalog
The pictures are not quite up-to-date. The pictures do not show the relay mount or the amplifier circuit. Updated on: 11/18/15
Demo room information