Simple Projection Manometer For Lecture Demonstrations JOHN W. MOORE1 and CARL M. FURGASONL
T
HE MANOMETER described below can be placed in the slide carrier of a standard lantern slide projector, so that lecture demonstrations involving pressure changes may be advantageously shown to large groups. The projection manometer is assembled from 18 inches of 6-mm. glass tubing and '/,-inch plywood. Different dimensions might, of course, be required to iit the particular projector with which the manometer is to be used. The complete unit, as shown in Figure 1,
University of Texas, Austin, Texas
If the range in pressure or liquid level is larger than the projected portion of the manometer tube, a flask fitted with a funnel may be connected between the
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A Figure 2.
Figure consists of the tubing held between two outside plates (Figure lb) which are separated by spacer blocks (Figures lc, id). The plates and blocks may be fastened together by brads or small screws. A six-inch transparent ruler may be used for the scale, fastened midway between the outer plates. The system being observed can be connected to either end of the manometer tube, as shown in Figure 2a or as in Figure 2b. Present address: Tennessee Valley Authority, Wilson Dam. Alabama.
manometer and the system under observation (Figure 3). The demonstrator may adjust the liquid level in the projection manometer to any desired point on the scale by manipulating the stopcock. For example, should the meniscus disappear from view on the screen, the stopcock is opened and the meniscus restored to its original position without appreciably disturbing the system.
Figure 3. A~ARATUS aon READJUSTING LEVEL IN MANOMETER
Acknowledgment The authors wish to express their appreciation to Dr. W. A. Felsing for his assistance in preparinp this mannscri~t.and t o ~ r Arthur . ~Ht'ureau for making the drawings.
