Oscillations and Waves > Waves > Phase and Group
Velocity
DCS# 3B30.20
SPEED OF SOUND IN AIR
APPARATUS
storage scope with
camera or teamlabs set-up
202-08-D-1
pair
of microphones
202-07-E1
wooden
blocks
202-01
tape
measure
101-05-E2
DESCRIPTION
Set microphones a known distance
apart. Clap the wooden blocks together. Measure the time
difference
between the peaks on the scope
and calculate the speed of sound in air. A frequency counter
could
be used in place of the storage scope.
Five meters is a convenient distance to use as it yields a time
difference of 15 ms, which spans the scope screen with the sweep rate
set to 2 ms/div.
