3B Scientific Greenhouse Effect Kit (115 V, 50__60 Hz) - Manual (Page 5)

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blackened metal disc, which becomes heated by the
radiation from the filament lamp. This emits infra-
red radiation that closely resembles the infra-red
radiation emitted by the earth. Measuring the in-
tensity of the transmitted fraction after this radia-
tion has been passed through an absorption cham-
ber, it can be observed that there is a considerable
reduction when the absorption chamber is filled
with a greenhouse gas.
For simplicity the greenhouse gas used in the ex-
periment is butane, which is provided in liquid form
in a bottle or can.
4. Preparation of absorption chambers
• If appropriate, seal the basic absorption cham-
ber and the “absorption chamber with taps” at
both ends with cellophane film.
• Alternatively, open the snap fittings at both
ends of the absorption chamber and take the
metal tube out of the support.
• Stretch the new film over the end of the tube
and secure it with adhesive tape (Sellotape,
Scotch tape, etc.).
• Put the metal tube back into the support and
close the snap fitting.
Also required:
1 Butane gas refill canister (lighter gas)
• Open both taps of the “absorption chamber
with taps“.
• Connect the butane gas canister to one of the
taps, using the thin flexible tube provided.
• Position the absorption chamber so that the
second tap is directed upwards as an exit for the
displaced air.
• Press the release nozzle for the butane gas can
so that the gas flows into the absorption cham-
ber.
• When the required amount of gas has entered
the absorption chamber, close the tap.
Note:
The absorption chamber will now be usable for
several hours. Alternatively, the gas can be admitted
during the experiment. In that case allow the gas to
flow in until the emerging long-wave infrared radia-
tion shows a marked reduction of intensity as com-
pared to normal air.
Instead of butane, the experiments can also be
performed with a propane-butane mixture, such as
is supplied in cartridges for gas torches. Here too it
is essential to follow fire protection regulations. The
absorption is about the same as with butane.
It is also possible to carry out the experiment with
carbon dioxide. However, in that case, the absorp-
tion of long-wave infrared radiation is not so
marked.
5. Experiment set-up
Additionally required:
1 Moll thermopile U8441301
1 Microvoltmeter (230 V, 50/60 Hz) U8530501-230
or
1 Microvoltmeter (115 V, 50/60 Hz) U8530501-115
Alternative:
1 Multimeter ESCOLA10 U8531160
1 Measuring Amplifier S U8532161
1 Transformer 12 V (230 V, 50/60 Hz) U8475430-230
or
1 Transformer 12 V (115 V, 50/60 Hz) U8475430-115
• Insert the rod that holds the lamp socket into
the farthest left hole of the base rail.
• Screw the reflector filament lamp in place and
align it along the base rail.
• Fill the plastic cuvette with water and insert it
into the next available hole nearest to the left-
hand end.
• Place the absorption chamber on its supporting
rods in the radiated beam, so that it is about 1
cm from the cuvette.
• Place the Moll thermopile at the right-hand end
of the base rail and connect it to a voltmeter.
• Turn the Moll thermopile towards the incoming
radiation and remove the protective cap.