3B Scientific Air Cushion Plate - Manual (Page 46)

Physical Experiments on the Air-Cushion Table
48
the magnetic barrier with the ceramic magnets
without any noticeable deflection. In various
cases it will change its direction of motion. It will
rebound only in very rare cases.
Interpretation:
In Rutherford’s scattering experiment almost all
alpha particles traverse the metal foil. Only a few
of them are deflected from their original direction.
Strong dispersion occurs only in very rare cases.
Note:
The influence of the magnetic barrier on the mo-
tion of the hover discs can be varied by placing
the barrier on the Plexiglas plate and setting the
plate to the desired height. The effect of the bar-
rier is enhanced by placing orange discs on the
ceramic magnets.
2.5.3 The Rutherford Atomic Model
Components:
Air-cushion table with fan
Overhead projector
Magnetic barrier, long
2 Pieces
Magnetic barrier, short 2 Pieces
Holding device 1 Piece
Plexiglas plate 1 Piece
Manipulating rod 1 Piece
Hover disc, orange 1 Piece
Hover disc, red 1 Piece
Model simulation:
Real Object Model
Atom Experiment surface of
the air-cushion table
Atomic nucleus Hover disc, orange
Electron Hover disc, red
How to proceed:
Align the air-cushion table horizontally. Attach
the magnetic barriers and the holding device to
the air-cushion table. Insert the Plexiglas plate
and position it closely above the experiment sur-
face. Place the orange disc in the middle of the
Plexiglas plate.
Turn the fan to a setting in which the red disc is
sure to lift off. Use the manipulating rod to move
it under the orange disc on the experiment sur-
face. Observe its motions. Then increase its ve-
locity by hitting it with the manipulating rod and
observe it again.
Result:
The red disc moves around the orange one on
varying paths. The parameters of the paths de-
pend greatly on the speed.
Interpretation:
These experiments provide simply illustrated con-
cept of the structure of an atom. They offer a viv-
id demonstration of the Rutherford atomic mod-
el, which was developed based on the results of
the scattering experiments.
Note:
The experiment can be varied by stacking sev-
eral orange discs and adjusting the height of the
Plexiglas plate accordingly.