PASCO TD-8551A MECHANICAL EQUIVALENT OF HEAT - Manual (Page 7)

012-04331E Mechanical Equivalent of Heat
3
Operation
Do not raise mass
more than about 3
centimeters above
floor.
Figure 6 Don't Raise Mass too High
Step by step instructions for using the Mechanical
Equivalent of Heat Apparatus are given on the following
pages. However, the apparatus will last longer and give
better results if you follow the guidelines listed below:
➀ Before performing the experiment, spray the surface
of the aluminum cylinder lightly with the included dry
powdered graphite.
The graphite ensures that the rope slides smoothly on
the cylinder, making it easier to provide a steady,
even torque, and greatly decreasing the wear on the
aluminum cylinder.
After several applications, the friction rope will be-
come impregnated, so you needn't continue to apply
the lubricant at every use.
➁
Mount the Mechanical Equivalent of Heat on a
level table.
If the apparatus is not level the rope will tend to slip
and bunch up on the cylinder, which makes it difficult
to maintain a steady torque.
➂
When turning the crank, never raise the mass higher
than about 3 cm from the floor (no higher than you
would care to have it fall on your little toe).
If the mass is raised higher, the crank can snap back
when released, which is not healthy for the equip-
ment, or for nearby people. Also, if it is allowed to
climb, the rope will likely start overlapping the next
turn which makes it climb even higher, producing a
dangerous situation
Aluminum Cylinder
Dry powdered
graphite
Figure 4 Lubricate Cylinder
Be sure the table is level.
Figure 5 Level Table