Now to make a plunger: Heat a piece of No. 2
tube 8½ inches from one and in the lamp flame, draw it out into
a nozzle, and break it off, leaving a small hole at the end of the
nozzle. Smooth the other end in the lamp flame, flare it out slightly,
allow it to cool, dip it into water and insert it into a small wet
coupling.
FIG. 70
A THIRD SYRINGE
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Now fill the large tube with water and insert
the coupling plunger (Fig. 70). Do you get a fine long stream?
Experiment 51. To make a diablo whistle.
Use the No. 6 tube and the No. 2 plunger
from Experiment 48, arrange as in Fig. 71, blow across
the top, and move the plunger up and down. Do you get a most diabolical
sound?
FIG. 71
THE DIABLO WHISTLE
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The sound is produced by the vibration of
the air column between the top of the tube and the top of the plunger.
Do you find that the pitch of the note is higher the shorter the air
column?
Experiment 52. Fun with the diablo whistle.
Start with the air column long and blow
the note, shorten it a little and blow the next note, continue, and
try
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