Description

Two black metal pillars on a grey metal base, both
drilled to hold metal specimens in the form of thin
rods. Three rods of different metals are provided
with thinner versions of two of these. An engraved
scale with a sprung metal pointer is attached to
one of the pillars to record the thermal expansion
of the rods. Heating can be either by a spirit lamp or
Bunsen burner. The spirit lamp has the advantage
that it can be placed under each rod and left
there. The Bunsen burner has to be hand-held but
gives greater heating. The effective length of the
rod when mounted between the pillars is 210mm.
The pointer has a velocity ratio of 2.5. Moderate
heating is sufficient to show that metals expand
when heated and that different metals expand by
different amounts. The apparatus, whilst clearly
showing qualitative comparisons, is not intended
to give accurate quantitative results.