
Speed
of Sound:
Overview:
Parents can help their students with this exercise using
readily available items to figure the rough speed of sound.
Incorporate this into your regular lessons on sound.
Teacher Preparation: Optional handout sheet describing
the procedure below.
Procedure Ideas:
 Discuss
the phenomenon of sound traveling much slower than light,
hence seeing distant actions before hearing their
accompanying sounds.
 Explain
how knowing the distance from an action and timing the
length of time a sound takes to reach us enables us to
calculate the speed the sound is traveling at.
 Brainstorm
with students situations where the time delay can be
confusing, such as at sporting events or public concerts.
 Brainstorm
with students ways they can estimate the speed with their
parents. Hint: An automobile is an easy way. Drive
from point A to B, using the odometer to go a fixed distance
such as a quarter mile or half kilometer. Using a stopwatch
(many digital wristwatches have one) clock the time delay of
slamming a door.
 Remember
to have students do the experiment several times to obtain
consistency.
Options/Variations:
Discuss the variable of temperature as it affects the speed
of sound; at 32F/0C the speed is 1085 feet per second. At
212F/100C the speed is 1268 feet per second.
