3B Scientific Air Cushion Plate - Handbuch (Seite 94)

43
Physical Experiments on the Air-Cushion Table
Interpretation:
In an insulator, the electrons are bound tightly to
the atomic nuclei. They cannot escape their posi-
tions even under the influence of an electric field.
2.4.10 Behavior of a Free Charge Carrier in
an Insulator
Components:
Air-cushion table with fan
Overhead projector
Magnetic barrier, long
2 Pieces
Magnetic barrier, short 2 Pieces
Holding device 1 Piece
Lattice model 1 Piece
Manipulating rod 1 Piece
Hover disc, red 25 Pieces
Hover disc, orange 1 Piece
Model simulation
Real Object Model
Part of an insulator Experiment surface of
the air-cushion table
Crystal lattice of
Lattice model
the insulator
Bound electrons
Hover discs, red
Bombarding Hover disc, orange
charge carrier
How to proceed:
Align the air-cushion table horizontally and at-
tach the magnetic barriers. Spread the red discs
evenly across the experiment surface. Attach the
holding device to the air-cushion table and insert
the lattice model. It should be positioned closely
above the experiment surface.
Turn up the fan to a setting in which all discs are
sure to lift off. One red disc should be positioned
under each hanging magnet. If necessary, use the
manipulating rod to ensure this arrangement.
Position the orange disc in a corner of the ex-
periment surface and hold it with the finger at
first. Then release it and observe the changes
caused by this hover disc.
Result:
The orange disc moves across the experiment
surface in a disorderly fashion, driving some of
the red discs from their positions. These discs
then move between the other bound discs as well,
but return to fixed positions after a certain pe-
riod of time.
Interpretation:
Bombarding an insulator with a fast charge car-
rier causes the release of some electrons under
its influence. These can migrate for a certain
period of time, allowing a current to flow in an
insulator. This is the case e.g. when specific non-
conductors are exposed to high-energy radiation.
Note:
The effect can be enhanced by removing the red
disc, which would be first hit by the orange disc.
2.4.11 Electric Conduction in a
Semiconductor – Intrinsic Conduction
(Demonstrated By Means of
Mechanical Forces)
Components:
Air-cushion table with fan
Overhead projector
Magnetic barrier, long
2 Pieces
Magnetic barrier, short 2 Pieces
Holding device 1 Piece
Lattice model 1 Piece
Manipulating rod 1 Piece
Hover disc, red 25 Pieces