3B Scientific Air Cushion Plate - Handbuch (Seite 70)

19
Physical Experiments on the Air-Cushion Table
Model simulation
Real Object Model
Vessel containing Experiment surface
the gas of the air-cushion
Walls of the vessel Magnetic barriers
Partition Magnetic piston
Gas molecules Hover discs
How to proceed:
Align the air-cushion table horizontally and attach
the magnetic barriers. Divide the experiment
surface in half using the magnetic piston, paral-
lel to the barriers nos. 1 and 2. For guidance of
the piston rod, place the guide piece for the
magnetic piston onto barrier no. 2.
Place two hover discs into each half.
Increase the fan setting so that both hover discs are
sure to float even when the impulse valve is opened.
Open the impulse valve repeatedly in order to set
the hover discs in the adjacent half of the experiment
surface into strong motion, while ensuring lesser
motion of the other two discs, if necessary by
slowing them down manually. Now quickly remove
the magnetic piston from the experiment surface
and observe the motion of all hover discs.
Result:
The fast discs partially transfer their energy onto
the slow ones. The mean velocity of all four hover
discs is lower after the removal of the piston than
the velocity of the two fast discs in the one half
and higher than that of the two slow ones in the
other half.
Interpretation:
When mixing two gases of different temperatures,
the resulting temperature is between the two ini-
tial temperatures. The reason for this is that the
molecules of the gas with the higher temperature
transfer part of their kinetic energy to the mole-
cules of the gas with the lower temperature.
Note:
The experiment can also be carried out with 8
green and 8 red hover discs. This is a better dem-
onstration of the conditions in a gas due to the
larger number of hover discs. However, it is more
difficult to maintain the difference in velocity.
For this reason, it is necessary to (manually)
accelerate the hover discs in one half and to slow
them down in the other.
2.1.9 Increase of Temperature in Gases when
Supplying Energy
Components:
Air-cushion table with fan
Overhead projector
Magnetic barrier, long
2 Pieces
Magnetic barrier, short 2 Pieces
Hover disc, red 12 Pieces
Hover disc, green 4 Pieces
Model simulation
Real Object Model
Vessel containing Experiment surface
the gas of the air-cushion
Walls of the vessel Magnetic barriers
Gas molecules Red hover disc
Molecules with Green hover disc
higher energy
How to proceed:
After aligning the air-cushion table horizontally,