Manual

3B SCIENTIFIC
®
PHYSICS
1
Kundt's tube U8432845
Instruction sheet
05/11 ALF
1 Movable plunger
2 Kundt's tube
3 Cork powder
4 Stand (not included)
5 Refill rail
1. Safety instructions
• Store the glass tube in a safe place where it
cannot be exposed to danger of shocks or
breaking.
• Do not expose the glass tube to any mechani-
cal stress or strain.
• Do not bend the movable piston while pushing
it in or pulling it out.
• Do not use the apparatus, if the glass tube is
damaged.
• Protect the apparatus from humidity and dust.
2. Description
By employing cork dust, a Kundt’s tube is used to
demonstrate the distribution of nodes and anti-
nodes in a standing sound wave. Using the appara-
tus, it is also possible to demonstrate that standing
waves are formed when a resonance condition is
fulfilled for sound wavelength λ and length s of the
vibrating air column in the tube such that:
s = n λ/2 for reflected waves with antinodes at the
open end,
s = (2n+1)λ/4 for reflected waves with nodes
(n = 1, 2….n) at the closed end.
The wavelength can be determined from the num-
ber of nodes n and the distance a between the first
and last nodes
λ = 2a/(n − 1).
The rod with the cork plunger seals the tube and is
used for changing the effective tube length to tune
the frequency of the resonant sound waves.
A whistle, a tuning fork or a loudspeaker driven by
a function generator can be used as a sound
source.
A funnel reduces the wave impedance at the open-
ing of the tube. As a result, more sound energy can
be introduced into the tube.
2.1 Scope of delivery
1 Glass tube
1 Movable piston
1 Funnel
1 Whistle
1 Refill rail
3. Technical data
Tube: 600 mm
Internal diameter: 17 mm
Glass thickness: 1.5 mm
Movable plunger: 280 mm x 3 mm dia.