3B Scientific Electroscope S - Manual (Page 2)

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Subject to technical amendments
© Copyright 2013 3B Scientific GmbH
4. Operation
To perform experiments, the following equip-
ment is also required:
Friction rods
1002709
Friction
rod Rubbing mate-
rial Charge po-
larity
PVC Plastic foil +
Acrylic
glass
Plastic foil -
To indicate the charge polarity the following
equipment is recommended:
Charge Indicator
1009962
4.1 Electroscope set-up
• Insert the frame into the base.
• Slide the aluminium rod vertically into the
frame.
• Attach the electroscope unit to the magnetic
holder.
• Place the pointer needle in such a way that
it automatically points to zero.
4.2 Charging up the electroscope by touch-
ing it with a statically charged body
• Rub the friction rod with the suitable mate-
rial.
• Touch the aluminium rod with the charged
rod. The pointer deflects.
• Remove the friction rod, the pointer remains
deflected.
• Touch aluminium rod with your hand. The
pointer returns to normal.
• Repeat the experiment with the second fric-
tion rod.
• Determine the sign of the charge using the
charge indicator.
4.3 Using electrostatic induction to charge
up the electroscope
• Approach but do not touch the aluminium
rod with the statically charged friction rod.
The pointer deflects.
• Remove the friction rod. The pointer returns
to normal.
• Again approach the aluminium rod with the
statically charged friction rod. Once again
the pointer deflects.
• Briefly touch the aluminium rod with your
finger to discharge it. The pointer deflection
disappears and returns to normal.
• Now remove the friction rod. The pointer
again shows deflection.
Fig. 1 Charging the electroscope using a statically-
charged friction rod
Fig. 2 Charging the electroscope using electrostatic
induction