9.
Miscellaneous
TACH
YM
ET
ER
31
CHASE-DURER
P R O F E S S I O N A L
2 0 0 M E T E R S
60
40
20
10
30
50
T R A C K M A S T E R
10
8
2
4
6
9
3
12
6
9
3
12
6
At
68 F
(20 C), sound travels at
344m
or
376yds
/
1,129ft
per second in air at sea level.
°
°
Example:
Sea level temp is
and
lightning to thunder measured time is
17.4
seconds. Distance of lightning strike point
is:
17.4s
x
1,129ft
=
19,644ft
17.4s
x
376yds
=
6,542yds
17.4s
x
344m
=
5,986meters
OR:
17.4s
/
4.68s
=
3.72 miles
17.4s
/
2.66s
=
6.54 thousand yards
17.4s
/
2.91s
=
5.98 kilometers
68 F
°
At
32
°
F
(0
°
C), sound travels at
332m
or
363yds
/
1,089ft
per second in air at sea level.
Therefore, at
32
°
F
(0
°
C) sound will travel:
1 mile
/ 1,760 yards / 5,280 feet in
1,000 yards
in
1 kilometer
in
4.85
seconds
2.75
seconds
3.01
seconds
NOTE:
Therefore,
68 F
(20 C) sound
1 mile
(1,760 yards / 5,280 feet) in
1,000 yards
in
1 kilometer
in
To estimate the distance to an event (such as an
explosion, muzzle flash, lightning, etc.), measure
the time from the visual flash to the sound and
multiply the seconds by the per second speed.
For example the measured lightning to thunder
time at
68 F
is
10
seconds.
10
x
344m
or
376yds
/
1,129ft
would produce
3,440m
or
3,760yds
/
11,290ft
. (
2.14miles
)
Alternately, you can divide the measured time at
68 F
by
4.68
to get miles (
10s
/
4.68
=
2.14miles
),
or
2.66
for thousand yard distance, or by
2.91
for
kilometers.
at
will travel:
°
°
°
°
4.68
seconds
2.66
seconds
2.91
seconds
