3B Scientific Wave Machine, Manual - Manual

3B SCIENTIFIC® PHYSICS
Elwe Didactic GmbH ▪ Steinfelsstr. 5 ▪ 08248 Klingenthal ▪ Germany ▪ www.elwedidactic.com
3B Scientific GmbH ▪ Rudorffweg 8 ▪ 21031 Hamburg ▪ Germany ▪ www.3bscientific.com
Subject to technical amendments.
Mechanical wave model 8431805
Instruction sheet
08/06 SP
1 2
1. Pendulum rod
2. Torsion string
1. Description
The mechanical wave model is used to demon-
strate the propagation, reflection, diffraction and
interference of waves.
A chain of double pendulums is threaded on a
bifilar torsion string. The set also includes extra
weights to alter the moment of inertia. Two han-
dles for either end allow you to excite waves by
hand.
2. Technical data
Wave model: 3 m length
Torsion string: 6.5 m length
Number of double pendulums: 79
Weight: 0.8 kg approx.
3. Operation
3.1 Assembly
• Fold the torsion string in half so that both
halves are the same length.
• Thread handle 1 into the loop of the string, as
shown in Fig. 1.
• Attach the pendulum bars by threading one
end of the string through one of their two
holes and the other end through the other
hole.
• Between each of the pendulum bars, run both
ends of the string through spacer tubes.
• Once all the bars are threaded onto the string,
tie the free ends onto handle 2.
3.2 Experiment procedure
• Clamp one handle of the apparatus in place or
request someone to hold it tight.
If the apparatus can be firmly fixed at one end,
reflection, interference or standing waves can be
induced. If the apparatus is held loose by another
person at its opposite end, the wave simply trails
away.
• Hold the torsion string taut.
• Make a turning motion by hand at the free
end. Continue to hold the torsion band taut.
• Turn the handle faster or slower to produce
the desired effect.
Fig. 1: How to thread the string through handle 1