This type of presentation is particularly effective in showing corro-
sion, lubrication principles, electrolytic disassociation of solutions,
and similar reactions.
24. Animated Devices
Construct transparent plastic models or mock-ups with movable
parts. Any such device should be built to fit within the 10- by 10-inch
dimensions of the projection stage. The projector can be refocused
as necessary to bring various elements of the device into sharp focus.
Typical of the plastic animated devices that can be constructed are
measuring scales, slide rules, electric meters, hand tools, basic mecha-
nisms, atomic models, biological structures, and floral shapes.
Figure 15. Animated devices made for use with projector.
25. Use of Two Projectors
Two or more projectors can be used in the solution of tactical prob-
lems involving team competition. Give each team a copy of the same
transparency, and arrange the projection screens so that they are not
visible to competing teams. If tramslucent screens are used, umpires
or observers can view the competition from behind the screens while
the screens are being marked.
Section IV. PREPARATION OF TRANSPARENCIES
26. Materials Used in Preparing Transparencies
a. Kit. A Signal Corps visual aid illustration kit (Sig C stock
No. 8P20-2083), which may be ordered through supply channels, con-
tains the following items:
(1) 24 mounts.
(2) 100 sheets of clear acetate.
(3) 6 film sheets.