3B Scientific Bolometer - Manual

3B SCIENTIFIC® PHYSICS
1
Bolometer U8461300
Instruction sheet
07/08 ALF
1 Hole for thermometer
2 Cardboard tube
3 End-plate
1. Description
A bolometer is used for measuring the heat radiation
from the sun.
The instrument consists of a solid aluminium
cylinder with a blackened end surface inside a
cardboard tube, which is blackened on its inner
surface and has two plastic end-plates. A hole is
provided in the tube and the cylinder for inserting a
thermometer.
The blackened surface of the aluminium cylinder
prevents reflection of the incoming heat radiation,
and a blackened cardboard tube screens the cylinder
from ambient background radiation.
2. Technical data
Aluminium cylinder:
≈ 30 mm × 40 mm Ø
Cardboard tube:
≈ 195 mm × 50 mm Ø
Weight: 350 g approx.
3. Sample experiments
To carry out the experiments the following
equipment is required in addition:
1 Thermometer +10 ... +30 °C U8451700
1 Tripod stand, 150 mm U13270
1 Stand rod, 470 mm U15002
1 Universal jaw clamp U13261
1 Universal clamp U13255
1 Digital stopwatch U11902
1 Set of Vernier callipers, 150 mm U10071
1 Electronic scale, 2500 g U42058
1 Pipette dropper
3.1 Measuring the quantity of heat transferred to
an aluminium body by solar radiation
Heat from the sun is transmitted to the earth by
thermal radiation. The intensity of the thermal
radiation depends on the position of the sun above
the horizon and the clarity of the atmosphere. The
earth’s atmosphere “swallows up” a fraction of the
solar radiation. That fraction may be smaller
according to how clear the weather is and how high
the sun is in the sky.