3B Scientific Thermal Expansion Apparatus S - Manual (Page 4)

4
(Note: at high altitudes, water boils at slightly less
than 100° C.)
• When steam has been passing through the rod for
about 1 minute and no more condensing steam is
emerging from the end of the rod, read off the larg-
est movement of the pointer.
5. Example calculation
Room temperature T
1
= 22°C
Temperature of steam = 100° C
Temperature rise
∆T= 78° C
Pointer movement for copper rod d = 32.5 mm
Extension w = 50
Length of rod l = 500 mm
α =
32 5
500 50 78
.
⋅ ⋅
= 16,7 · 10 –6 /° C
Table of values:
Copper: 16.8 · 10
-6 /° C
Iron: 12 · 10 -6 /° C
Glass: 9 · 10 -6 /° C
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