3B Scientific Battery Box User Manual
3B SCIENTIFIC® PHYSICS
U20600 Kundt’s tube
U20601 Microphone probe
U20602 Battery box
Operating instructions
11/02 ALF
®
The equipment set comprising Kundt’s tube and
accessories is meant to display stationary sound waves
with open or closed tube ends and determine
wavelengths in air and other gases.
1. Safety instructions
• Protect the microphone and loudspeaker against
moisture.
• The external voltage through the microphone’s
connection line should not exceed 5V .
• Do not clean the acrylic glass body with aggressive
agents or solvents.
2. Description, technical data
The equipment set designated Kundt’s tube consists of
an acrylic-glass tube with a scale, two removable end
plates and an integrated hose nipple for filling the tube
with various gases. One end plate is furnished with a
loudspeaker, the other with a bore and guide for
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mounting a movable piston or microphone probe
(U20601).
The equipment set includes two clamps for mounting
Kundt’s tube on a tripod, and cables for connecting the
loudspeaker.
Length: 1000 mm
Diameter: 70 mm
Hose nipple: 7 mm Ø
Scale: 1000 mm
Division: mm and cm
Drawing:
1 End plate with loudspeaker, 4-mm jacks and hose
nipple
2 Resonance tube
3 End plate with bore and guide for mounting a piston
or microphone probe
4 Microphone probe
5 Microphone
6 Scale
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3
6
5
4
3
2.2. Microphone probe
The microphone probe is used to measure changes in
sound pressure inside Kundt’s tube.
A miniature microphone is attached to the end of a long
rod made of stainless steel. It is connected by means of
a 5-pole DIN plug to the battery box (U20602). This battery
box also has a terminal for connecting an oscilloscope or
voltmeter. The microphone probe can be connected
directly to the digital counter (U21000) via the adapter
U20603.
Microphone’s frequency range: 20 Hz to 20000 Hz
Probe’s dimensions: 740 mm x 8 mm Ø
Connection cable’s length: 2 m
2.3. Battery box
The battery box supplies the microphones (for instance,
U20601 or U18030) and other analog sensors with a power of 5 V DC so that they can be connected directly with
a measuring device or an oscilloscope.
The box consists of a compartment for a 9-V alkaline
battery which supplies the required 5 V DC via a regulator.
Two 6-pole DIN jacks (180°) and one 8-pole DIN jack (270°)
are available as input channels. Two 5-pole DIN jacks and
two 4-mm safety jacks serve for connecting measuring
devices.
Dimensions: 143 mm x 84 mm x 37 mm
Note:In order to make simultaneous use of the microphone probe U20601 and an oscilloscope, connect the
microphone probe to the sensor input (3) and the oscilloscope to the output (2).
3. Sample experiments
3.1 Stationary waves in a closed tube
3.2 Stationary waves in carbon dioxide
3.3 Stationary waves in a tube with one closed end
3. Stationary waves in an open tube
3.5 Changes in the air column
Sound source: Tuning fork or loudspeaker
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4
2
3
1 DIN jacks for connecting measuring devices
2 4-mm safety jacks for connecting an oscilloscope,
voltmeter or interface
3 DIN jack for connecting various sensors or a LabPro
interface via an output adapter
4 DIN jacks for connecting microphones
To perform these experiments, additional use is required of a function generator (for example, U21015)
to excite the loudspeaker , and an oscilloscope (for
instance, U11175) to display the oscillation nodes
and antinodes.
3.6 Determination of the speed of sound in air
• Install Kundt’s tube with closed ends and the microphone probe on a tripod; connect a function
generator (for instance, U21015) and an oscilloscope
(for instance, U11175).
• Apply a frequency f = 2700 Hz to the loudspeaker.
• Move the microphone probe past the nodes and
measure the intervals between them using the scale.
• The average interval between two neighbouring
nodes turns out to be 6.3 cm.
• This results in a wavelength λ = 12.6 cm.
• The speed of sound c is calculated with the for-
mula c = f ·
c = 2,7 · 103 · 12,6 · 10–2 m/s = 340 m/s
λ
3B Scientific GmbH • Rudorffweg 8 • 21031 Hamburg • Germany • www .3bscientific.com • Technical amendments are possible
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