User guide

Elwe Didactic GmbH • Steinfelsstr. 6 • 08248 Klingenthal • Germany • www.elwedidactic.com
3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany • www.3bscientific.com
Subject to technical amendments
© Copyright 2007 3B Scientific GmbH
4. Operation
In order to conduct the experiments, the following
apparatus is additionally required:
1 Tuning fork 1700 Hz
U8431020 or
1 Pneumatic loudspeaker
U8432680 with
1 Function generator U8533510
Cork powder U8432850
1 Metre scale
U8401550
1 Stand for coils
U8496150
• Use a refill rail to introduce a small quantity of
cork dust into the tube.
• Slightly tilt the tube and shake it gently till the
cork dust has uniformly spread throughout the
length of the tube.
• Position the Kundt’s tube on the stand so that
the strip of cork dust is at the bottom.
• Slowly rotate the tube along its length in order
to spread the cork dust along the walls too.
• For determining the wavelength, fit the tube
with a horn.
• For determining resonance conditions, conduct
the experiment without a horn.
It is recommended that a 1700-Hz tuning fork be
used. The fork produces a resonant wavelength λ
of 0.2 m for the 0.6-m tube. When the wave is re-
flected at the open end, antinodes are produced at
both ends. When the wave is reflected at the closed
end, nodes are produced at both ends.
• Position the sound source right at the end of
the tube.
• If blowing a whistle, make sure that it is per-
pendicular to the tube. This is necessary to
prevent any air from entering the tube.
• When using a tuning fork, strike it and quickly
hold it with its prongs in the direction of vibra-
tion in front of the opening of the tube or the
horn.
• When using a loudspeaker, gradually change
the frequency on the function generator to
identify the resonance frequency. Effective
range: between 600 Hz and 8000 Hz.
• To tune a closed tube to the resonant length,
gradually move the movable plunger.