LIGHT GUIDE DEMONSTRATOR 1449
An S-shaped acrylic bar 220 x 20 x 20mm which can be used with the Ray Box to demonstrate total internal reflection and help students to understand the principles of optical communications. The bottom of the bar is painted white to aid visibility.

WHISTLE 1450
Cylindrical, mouth-blown type.

SIREN DISC 1452
The disc has four sets of drilled holes arranged in co-centric circles. The number of holes in each circle are 34,45,54 and 72 respectively. For use with whirling stand.

DOPPLER EFFECT DEMO KIT 1454
Consists of 3 precision machined aluminium alloy tuning forks with holes in the stems to accept a heavy braided cord. Kit contains 256Hz and 1,024Hz forks, 50Ft cord, and tuning fork activator.

CROVA’S DISC 1456
For showing progressive waves. Printed on a white plastic disc which is free to rotate in an outer case. Size: 225x225mm, with viewing slot.

WAVE MOTION MODEL 1457
A great illustration of wave motion, this mechanism demonstrates longitudinal and transverse waves by hand-cranking a set of eccentric aluminium disks. Model is mounted on a sturdy wooden base.

WAVE STICKS SET 1458
Demonstration set used in the exploration of wave speed; reflection and refraction polarities, and transformers and impedance. Includes one assembled unit and 400 sticks, with special narrow tape to construct another. Includes instructions.

WAVE MOTION APPARATUS 1459
The inertia of the massive rods makes for slow and majestic displays of torsional waves that appear as transverse waves when viewing the colorful ends of the rods. Wave fundamentals are easily introduced and include frequency, wavelength, amplitude, reflection and phase. Can be also operated in vertical format. Size: W 30cm x L 90cm.

VIBROGRAPH 1461
This is an instruments for teaching the principle of indirect measurement. The stylus of the tubing fork and the needle on the pendulum each make a trace on the smoked glass plate as the carriage is moved from right to left. Prior to the "run" the pendulum frequency is measured by timing with a stopwatch. The unknown frequency of the tuning fork is then determined by comparing the traces.

EVEN FREQUENCY TUBING FORK SET 1463
Six unmounted tuning forks precision machined from aluminum alloy. Set consists of 125Hz, 250Hz, 500Hz, 1000Hz, 2000Hz and 4000Hz.

ADJUSTABLE TUNING FORK 1465
Precision-grade aluminium alloy tuning fork with sliding weights on each tine. Weights adjust to deliver tones in C-128, D-144, E-160, F-170.7, G-192, A-213.3, and B-240 frequencies. Overall length, 8”.

RUBBER HAMMERS 1468
Used to activate tuning forks. Available with a soft, medium, or hard sphere and mounted on a sturdy, wooden handle.
(a) Soft (Frequencies of 32 to 256Hz)
(b) Medium (Frequencies of 256 to 1024Hz)
(c) Hard (Frequencies of 1024Hz)

ACOUSTICAL PHYSICS DEMONSTRATION 1473
Consists of one 880-Hz aluminium alloy tuning fork, a rubber striking pad, and one 880Hz ames tube (a half-wave open tube to produce an integrally coupled tuning fork resonator). Can be used to demonstrate sympathetic vibration, "beat" phenomenon, energy transfer, Doppler effect, and more.

KUNDT'S TUBE APPARATUS 1475
Consists of a glass tube heavy walled 1350 x 32 mm with cork bung, short & long ebonite rod, cork pistons, mounted on a polished wooden board 1520 x 125 x 22 mm with spring clamps. The long ebonite piston is supported by wood clamp secured with wing nuts.