Quick answer. For sound and wave apparatus the decision that matters is buying working sets, not single codes. A ripple tank (PSWB-0010) arrives unusable without its power supply (PSWB-0012), its accessory set (PSWB-0013) and a stroboscope (PSWB-0018 or PSWB-0019), and it only works if it can be levelled, because ripple speed depends on water depth. A sonometer needs spare wires, a pulley and a weight hanger with masses, which are routinely not supplied. Tuning fork sets need their frequencies listed and a rubber-ended hammer. Ask for each of these to be quoted and confirmed as a set.
Thirty-three sound and wave apparatus are listed here as PSWB-0001 to PSWB-0033, with ten further items appended under code formats belonging to other categories. The sound half is the classical bench: sonometers, tuning forks, resonance tubes, organ pipes, Kundt's tube and Melde's apparatus. The wave half is the ripple tank and its accessories. Two things matter more than any of the product names. A ripple tank is only as good as its water depth and its levelling, and it needs a stroboscope to be useful at all. And a stroboscope needs a warning given to the class before it is switched on, for the reason set out below.
| Topic | Codes | Apparatus |
|---|---|---|
| Water waves | PSWB-0010 to PSWB-0013 | Ripple tank, dual-purpose ripple tank, its power supply and its accessory set |
| Freezing the pattern | PSWB-0018, PSWB-0019 | Digital stroboscope, hand stroboscope |
| Strings and the sonometer | PSWB-0015, PSWB-0016 | Student and wooden sonometers |
| Standing waves on a string | PSWB-0022, PSWB-0028, PSWB-0020 | Electrically maintained tuning fork for Melde's experiment, electrical vibrator for the same, electrical tuning fork |
| Air columns and resonance | PSWB-0003 to PSWB-0009 | Organ pipes closed, open and sliding; four resonance apparatus variants |
| Tuning forks | PSWB-0021, PSWB-0023 to PSWB-0027 | Hammer, pair on box for beats, forks on resonance box, sets of four, eight and thirteen |
| Speed of sound in solids | PSWB-0002 | Kundt's tube apparatus |
| Wave propagation models | PSWB-0029 to PSWB-0031, PSWB-0033 | Helical spring and slinky, wave motion apparatus, Powell wave machine |
| Other | PSWB-0001, PSWB-0014, PSWB-0017, PSWB-0032 | Buzzer in vacuum, Savart's toothed wheels, stethoscope, whirling table |
More ripple tank demonstrations fail for mechanical reasons than for any fault in the physics, and all of them are avoidable:
A flashing light in a certain range of rates can provoke a seizure in a person with photosensitive epilepsy, who may not know they have it. This is a short, specific precaution rather than a reason to avoid the apparatus. Before a stroboscope demonstration, say what is about to happen, give anyone who prefers to the chance to leave or look away, keep the room lights on so the contrast is lower, avoid lingering in the most provocative range of flash rates, and work up to the rate you need rather than sweeping through. For the digital unit (PSWB-0018) ask the rate range and the display resolution, since the measurement depends on reading the rate accurately; the hand stroboscope (PSWB-0019) has no such hazard and is the safer choice for a class exercise, so ask how its slot count and speed are determined.
Tuning forks. Ask whether the frequency is stamped on each fork and what the frequency tolerance is, because every calculation uses that number. For the sets, ask which frequencies the set of four, the set of eight and the set of thirteen contain, since a set that misses the frequency your experiment specifies is no use. Ask whether a rubber-ended hammer (PSWB-0021) is included with each set, and make it a rule that forks are struck only on the hammer or a rubber pad: striking a fork on a bench or a metal edge chips the prong, alters its frequency and makes the fork useless for measurement. Ask also what the resonance box (PSWB-0024) is tuned to, since a box only amplifies the fork it was made for.
Sonometers (PSWB-0015, PSWB-0016). Ask what comes with the instrument: the wire, and spare wires of the gauges the experiment needs, since wires break; the bridges; the pulley; and the weight hanger with its masses, which are what set the tension and are routinely not supplied. Ask the scale length and division along the bed. One safety point: a wire under tension can snap and whip, so do not tension beyond what the experiment asks, keep faces away from the line of the wire while loading, and specify eye protection for the tensioning step.
Four resonance apparatus codes (PSWB-0006 to PSWB-0009) and three organ pipe codes (PSWB-0003 to PSWB-0005) overlap considerably, so ask for the specification of each and buy one of each kind. For a resonance tube ask the tube length and bore, how the water level is raised and lowered, whether a reservoir and a scale are fitted, and whether the scale reads directly in centimetres from the tube mouth, which saves a conversion step for every reading. For the organ pipes ask the lengths and whether the sliding pipe (PSWB-0005) reads its length on a scale, and whether the set is intended to be blown by mouth or from a blower; if by mouth, that is one student per pipe and a hygiene consideration for a shared set.
For Kundt's tube (PSWB-0002), ask what the indicating powder is and whether it is supplied, how much of it a class gets through, and how the rod is excited. Keep the powder dry, do not blow it about, and avoid raising a cloud of it; sweep spills rather than brushing them into the air.
PSWB-0001, buzzer in vacuum. This demonstrates that sound needs a medium, and it needs a vacuum pump and a bell jar, so ask whether the jar and base plate are supplied and whether a pump is included or must come from elsewhere. Evacuated glassware fails suddenly rather than cracking first, so ask what the jar is rated for, inspect it for chips before every use and specify eye protection while pumping down.
PSWB-0032, whirling table. This is circular-motion apparatus rather than wave apparatus, and it spins a mass on an arm. Ask the maximum speed, what guarding is provided, how the mass is secured and whether there is a brake, and keep the class outside the swept circle.
Two thermometer codes appear at the end of this listing, a wide-range digital thermometer and a mercury thermometer, and they are the two codes missing from the sequence under Thermometers, so look for them there rather than here. Seven further items carry a quite different code format and are mechanics apparatus: an air-flow generator for an air track, a gravity laboratory set, an electronic timer with photogates, a constant-speed car, a dynamics car and inclined-track set, a measuring rulers set and a ball bearing, plus a mechanical box. They belong with Mechanics Physics Lab. The electronic timer with photogates is worth knowing about if you are buying mechanics apparatus, because it is the timing method those experiments need and it is not listed under mechanics at all.
Quote the code rather than the name. Apostrophes are missing from Kundt's, Savart's and Melde's, one name spells Melde's two different wrong ways across two codes that cover the same experiment, one has resonance misspelled, one is truncated mid-word, four resonance variants and five tuning-fork sets overlap, and ten appended items use code formats from other categories, one of them containing a slash. Ask also for dimensions and materials, the manual with the expected result, the quantity per student group, spare wires and powder, the supply voltage, frequency and plug type for your country, and the warranty. Any frequency or dimension quoted is confirmed in writing on the quotation; ask for its basis.
Interference, diffraction and the stroboscope's optical cousins are under Optics Physics Lab. Pendulums, circular motion and the timing equipment these experiments assume are under Mechanics Physics Lab. The vacuum pump and evacuated glassware questions recur under Fluid Mechanics Physics Equipments, and supplies and meters under Electricity and Cell Lab. Parent range: Physics Lab Equipments.
If you are buying a ripple tank, ask for it as a working set rather than as a tank. For example Ripple Tank (PSWB-0010) with its power supply (PSWB-0012), the accessory set itemised (PSWB-0013) and a stroboscope (PSWB-0019), four sets, with the levelling arrangement and the low-voltage position confirmed in writing. For sound, Sonometer Student (PSWB-0015) with spare wires, hanger and masses, and a tuning fork set with the frequencies listed. Contact Ray Export for prices, frequencies and lead times.
The tank alone is the commonest way this apparatus arrives unusable. Order the power supply (PSWB-0012) unless the tank includes its own, and ask whether it drives the lamp, the vibrator motor or both. Order the accessory set (PSWB-0013) and ask exactly what it contains: a useful set has point and straight dippers, straight and curved barriers, an adjustable single and double slit, and a shallow-water insert for refraction. Add a stroboscope, PSWB-0018 or PSWB-0019, because continuous ripples are a blur. Ask about levelling screws, draining, and a stand with a screen underneath.
Usually because the tank is not level. It runs with only a few millimetres of water, and ripple speed depends on that depth, so an unlevel tank has a varying depth, a varying wave speed and a distorted pattern that looks like a result. Ask whether the tank has levelling screws and a means of checking level, and treat levelling as part of setting up. Water and mains electricity also meet in this apparatus: ask whether the lamp and motor run at low voltage, and if any part is mains-fed, insist on a residual-current device on that bench.
Yes, with a short, specific precaution. A light flashing in a certain range of rates can provoke a seizure in a person with photosensitive epilepsy, who may not know they have it. Before the demonstration, say what is about to happen and give anyone who prefers the chance to leave or look away; keep the room lights on to lower the contrast; and work up to the rate you need rather than sweeping through. The hand stroboscope (PSWB-0019) has no such hazard and is the safer choice for a class exercise; for the digital unit (PSWB-0018), ask the rate range and display resolution.
Ask whether the frequency is stamped on each fork and what the frequency tolerance is, because every calculation uses that number. For the sets of four, eight and thirteen, ask which frequencies each contains, since a set that misses the frequency your experiment specifies is no use. Ask whether a rubber-ended hammer (PSWB-0021) comes with each set, and make it a rule that forks are struck only on the hammer or a rubber pad - striking a bench or metal edge chips the prong and alters the frequency. Ask what the resonance box (PSWB-0024) is tuned to, since it only amplifies its own fork.
Four resonance apparatus codes (PSWB-0006 to PSWB-0009) and three organ pipe codes (PSWB-0003 to PSWB-0005) overlap considerably, so ask for the specification of each and buy one of each kind. For a resonance tube, ask the tube length and bore, how the water level is raised and lowered, whether a reservoir and scale are fitted, and whether the scale reads directly from the tube mouth. For organ pipes, ask the lengths, whether the sliding pipe (PSWB-0005) has a scale, and whether the set is blown by mouth or from a blower - by mouth means one student per pipe and a hygiene consideration.
A sonometer wire under tension can snap and whip, so do not tension beyond what the experiment asks, keep faces away from the line of the wire while loading, and specify eye protection. For Kundt's tube (PSWB-0002), keep the indicating powder dry and avoid raising a cloud of it; sweep spills rather than brushing them into the air. The buzzer in vacuum (PSWB-0001) needs a bell jar and a vacuum pump - ask whether they are supplied - and evacuated glass fails suddenly, so check the jar's rating, inspect it for chips before every use and specify eye protection while pumping down.
Ray Export is a manufacturer and exporter of laboratory, scientific and educational equipment based at Plot No. 449, HSIIDC Industrial Area, Saha, Ambala, Haryana 133104, India. Enquiries: [email protected], +91-9817319615.
Written by Palak Mall, Senior Content Writer. Technically reviewed by Arvind Kumar, Lab Equipment Specialist, 12+ years in laboratory and testing instrumentation. Last updated: 17 October 2026.
Specifications - tank levelling and supply voltage, accessory contents, stroboscope rate range, fork frequencies and tolerance, tube and pipe dimensions, and the whirling table's maximum speed and guarding - are confirmed in writing on the quotation. For certificates, standards or approvals, contact us for the latest copies of the relevant certificates. No price is quoted on this page. Listing notes: apostrophes are missing from Kundt's, Savart's and Melde's; Melde's is spelled two different wrong ways across two codes for the same experiment; one name misspells resonance and one is truncated mid-word; the resonance variants and tuning fork sets overlap; the whirling table (PSWB-0032) is circular-motion rather than wave apparatus; and ten appended items use code formats from other categories, one containing a slash, including two thermometers that belong under Thermometers.
For use on pump plate not less than 15 cm. diameters Electric Bell working on 4-6 volts AC/DC, suspended on elastic rope in bell jar. Fine looped wire connections with terminals mounted in elastic bung fixing the jar.
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Organ pipe is made up of varnished wood with glass in front and membrane suspended over cord to show positions of nodes and antinodes, overall length 760 mm.
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Glass Tube of size 84cm long and 2.5cm dia rested on stand with clamp, with 500ml glass bulb supported on iron ring, joining rubber tubing and spring clip.
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