3B Scientific Air Cushion Plate - Manual (Page 30)

Physical Experiments on the Air-Cushion Table
30
Result:
As an increased amount of energy is supplied,
the motion of the hover discs becomes stronger.
They perform their oscillating motions at higher
amplitudes, exchange their locations more fre-
quently and move from one place to another at
higher speed.
Interpretation:
When supplying energy to a liquid, the mean ki-
netic energy of the molecules increases. The tem-
perature rises.
2.2.3 Diffusion of liquids
Components:
Air-cushion table with fan
Overhead projector
Magnetic barrier, long
2 Pieces
Magnetic barrier, short 2 Pieces
Hover disc, red 20 Pieces
Hover disc, green 20 Pieces
Model simulation
Real Object Model
Vessel containing Experiment surface of
the liquid the air-cushion table
Walls of the vessel Magnetic barriers
Molecules of Red hover discs
one liquid
Molecules of the
Green hover discs
other liquid
How to proceed:
Align the air-cushion table horizontally and place
the magnetic barriers on the experiment surface.
Spread the hover discs evenly across the entire
experiment surface so that all green discs are ar-
ranged in one half and all red ones in the other
half and the line dividing them runs parallel to
barriers nos. 1 and 2.
Turn the fan to a setting in which the hover discs
are sure to float even when opening the impulse
valve. Observe the motions of the hover discs,
especially in the area around the borderline.
Result:
The hover discs gradually mix in the area of the
borderline as a result of the occasional transla-
tional motions. With time, more and more red
discs move into the area of the green ones and
vice versa. After some time, the discs have mixed
completely.
Interpretation:
The disordered motions of the molecules causes
the liquids to mix by themselves. Due to the low
translation speed the diffusion in liquids occurs
much slower than in gases.