https://physlab-wiki.com/ 2026-04-19T16:44:59+00:00 https://physlab-wiki.com/ https://physlab-wiki.com/lib/tpl/UChicago/images/favicon.ico text/html 2021-10-14T13:09:56+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/beat_glockenspiel?rev=1634231396&do=diff Beat Xylophone A xylophone with bars that resonate at frequencies increasing sequentially in one Hertz increments is used to generate audible beat frequencies. A microphone and loudspeaker are available for large classes. L3 PIRA DCS 3B60.XX text/html 2023-04-19T16:23:07+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/beats_generator?rev=1681935787&do=diff Beats Generator A two channel sine wave generator is used to generate a combination of signals at two slightly different frequencies. The output is made audible to the class with a loud-speaker. The signals, along with a Fourier spectrum, may be viewed using a projection oscilloscope. text/html 2023-04-19T16:26:08+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/bell_in_a_vacuum?rev=1681935968&do=diff Bell in a Vacuum The sound from a mechanical doorbell inside a bell jar diminishes as the air inside the bell jar is removed. Setup Turn on the alarm and put it on the platform and put the jar on it, ensuring that the platform and jar are properly greased and that there aren't any openings (ie, center the jar properly). You will hear the sound slightly muffled. With one of the valves closed and the other open and connected to the vacuum pump, suck out the air. As you do so, you'll hear alar… text/html 2023-04-19T16:28:32+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/circular_vibrational_modes?rev=1681936112&do=diff Circular Vibrational Modes A wire loop is driven into resonant vibration using a mechanical driver. Several orders of resonance may be observed by sweeping the frequency of the drive Setup Attach the loop to the mechanical driver using the banana jack connection. Try not to push too hard onto the diaphragm (lock the driver). Tune the frequency of the driver to find the resonances. The current attachment has a resonance at around 6-7 Hz and another at around 12-13 Hz. To dive the oscillation… text/html 2023-04-19T16:29:22+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/doppler_frisbee_and_ball?rev=1681936162&do=diff Doppler Frisbee and Ball A frisbee and ball each have battery-powered tone generators attached. One can hear the tone's pitch change as they are tossed back and forth. Setup Turn on and throw around. Pitch will increase or decrease if they are moving towards or away from the (stationary) listener, respectively. text/html 2023-04-19T16:29:45+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/longitudinal_wave_machine?rev=1681936185&do=diff Longitudinal Wave Machine A series of rods connected by springs exhibits the behavior of a longitudinal wave. A clamp is available to illustrate reflection from both free and fixed ends. Setup Place on table and use. L3 PIRA DCS 3B20.30 text/html 2021-09-24T15:24:24+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/microwave_doppler_beats?rev=1632511464&do=diff Microwave Doppler Beats A microwave transmitter and receiver are set up with a sheet metal reflector such that the receiver is simultaneously sensitive to direct and reflected radiation. When the reflector is moved the frequency of the reflected radiation changes slightly resulting in beat frequencies at the receiver. The beats are made audible with a powered audio speaker. text/html 2023-04-20T14:32:27+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/projection_ripple_tank?rev=1682015547&do=diff Projection Ripple Tank A ripple tank is used in conjunction with an overhead projector to show wave properties including Huygen's principle, interference, and refraction. The agitator may be configured to generate plane waves or two separately phased circular waves. A variety of objects used for creating barriers, slits, and lenses is available. text/html 2023-04-20T16:55:47+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/ropes_and_spring_attached_to_wall?rev=1682024147&do=diff Ropes and Spring Attached to Wall A light rope, heavy rope, and long spring are attached to the wall. Properties of transverse waves including wavelength, frequency, phase velocity, superposition, and reflection may be shown. Setup Tie/attach them to the hooks on the lecture hall walls. For the rope, hold it taut and pluck it; that gives you a nice traveling wave. text/html 2021-09-24T15:27:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/shive_wave_machine?rev=1632511668&do=diff Shive Wave Machine Waves are generated in a series of rods that is joined by a central wire. The ends of the rods are fluorescent so that they stand out when illuminated with a blacklight in a darkened room. Numerous wave concepts may be demonstrated with this device including interference, standing waves, and reflection from fixed and free boundaries. text/html 2021-09-24T16:36:02+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/shive_wave_machine_pulley_driver?rev=1632515762&do=diff Shive Wave Machine Pulley Driver Not available A motorized pulley arrangement allows the Shive wave machine to be driven at both ends simultaneously with adjustable frequency and phase difference. PIRA DCS 3B10.30 text/html 2021-09-27T10:51:48+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/slinkys?rev=1632754308&do=diff Slinkys A variety of Slinkys are available to demonstrate properties of longitudinal and transverse waves including wavelength, frequency, phase velocity, transmission and reflection at a boundary, and superposition. text/html 2023-04-20T17:11:38+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/sound_wave_interference?rev=1682025098&do=diff Sound Wave Interference Two separated, identical speakers on a turntable are connected to a sine generator. A listener will hear sound from the two speakers interfere destructively as the turntable is rotated. One may also poll the class at a single position of the turntable to identify locations where the destructive interference condition is met. text/html 2021-09-27T10:53:36+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/speaker_twirl?rev=1632754416&do=diff Speaker Twirl A small speaker connected to a sine wave generator is swung around. The tone coming from the speaker is clearly shifted in pitch owing to the Doppler effect. L3, A0 PIRA DCS 3B40.10 text/html 2021-09-27T10:54:55+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/standing_waves_on_a_string?rev=1632754495&do=diff Standing Waves on a String A sine generator is used with a modified loudspeaker to drive a taut string. By sweeping the sine generator one may find the string's resonant frequencies. The amplitude of the string's motion is large enough so that the standing wave patterns are clearly observed. A black light may be used to illuminate a white or fluorescent string. Alternatively, a strobe light may be used to create the illusion of slowing down or freezing the motion. text/html 2021-09-27T10:55:39+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/tunable_tuning_forks_with_resonant_cavities?rev=1632754539&do=diff Tunable Tuning Forks with Resonant Cavities A pair of tuning forks mounted to resonant cavities may be separately tuned by means of a clamp which slides along one side of the fork. A variety of acoustic phenomena may be explored including beats and sympathetic resonance. text/html 2021-09-27T10:44:53+00:00 Anonymous (anonymous@undisclosed.example.com) https://physlab-wiki.com/physicsdemos/waves_and_optics/wave_motion/tuning_forks_with_ames_tube?rev=1632753893&do=diff Tuning Forks with Ames Tube Two tuning forks and a combination tuning fork-resonant cavity known as an ames tube may be used to show a variety of acoustical phenomena including beats, tuned cavities, sympathetic resonance, and mechanical coupling. The tuning forks resonate at frequencies 3 Hertz apart. The ames tube resonance matches that of one of the tuning forks.