3B Scientific Air Cushion Plate - Manual (Page 39)

Physical Experiments on the Air-Cushion Table
40
motions. Then place the orange disc onto the
Plexiglas plate above the center of the experi-
ment surface. Its magnet should face downwards
so that the aluminum discs are repelled. Set the
Plexiglas plate to different heights to vary the
influence of the orange disc on the aluminum
ones. Observe their motions.
Result:
At first, the hover discs move from one electrode
to the other and back. With the exception of few
mutual interferences, these motions are mostly
straight.
The influence of the orange disc is a major im-
pediment to these motions. The aluminum discs
can often only succeed in reaching the opposite
side after taking major detours. The lower the
Plexiglas plate is set, the stronger the interfer-
ence by the orange disc will be.
Interpretation:
Conduction electrons move practically unimped-
ed between the lattice elements of a metal. How-
ever, near the lattice element there is strong in-
terference.
Notes:
The fact that the directed movement of the elec-
trons only occurs from the cathode to the anode
is neglected intentionally.
2.4.6 Motion of an Electron in a Metal
Lattice Under the Influence of the
Electric Field – Ohmic Resistance
(Demonstrated By Means of
Mechanical Forces)
Components:
Air-cushion table with fan
Overhead projector
Magnetic barrier, short
1 Piece
Holding device 1 Piece
Lattice model 1 Piece
Manipulating rod 1 Piece
Hover disc, orange 1 Piece
Model simulation
Real Object Model
Part of a metallic Experiment surface of
conductor the air-cushion table
Metal lattice Lattice model
Strength of the Inclination of the
electric field experiment surface
Electron Hover disc
How to proceed:
Align the air-cushion table horizontally. Turn
magnetic barrier no. 2 by 180° and place it onto
its position on the experiment surface. Attach the
holding device to the air-cushion table and insert
the lattice model. Slide it along the groove of the
holding device until its edge at barrier no. 2 is
positioned above the last row of holes in the air
jet plate. This is to produce an approx. 3-cm wide
strip between the lattice model and the pressure
chamber through which the hover discs can be
placed onto the experiment surface. Set the lat-
tice model to the lowest position. Use the adjust-
ing screw at barrier no. 2 to select a slight incli-
nation of the table by lowering the table part at
this side. Place the hover disc onto the experi-
ment surface next to the pressure chamber.
Turn up the fan to make the hover disc float. Ob-
serve its motions and those of the hanging mag-
nets. Repeat the experiment selecting different
degrees of inclination for the experiment surface.
Result:
The lattice model influences the motions of the