Student Exploration: Longitudinal Waves
Vocabulary: antinode, compression, displacement, frequency, interference, longitudinal wave,
medium, node, rarefaction, standing wave
Prior Knowledge Question (Do this BEFORE us
...
Student Exploration: Longitudinal Waves
Vocabulary: antinode, compression, displacement, frequency, interference, longitudinal wave,
medium, node, rarefaction, standing wave
Prior Knowledge Question (Do this BEFORE using
the Gizmo.)
In many science fiction movies, an evil alien
spaceship explodes with an enormous KABOOM!!
Suppose you were floating in space at a safe distance
from a large explosion such as the supernova at left.
Do you think you would you hear anything? Explain.
I don’t think so, the sound doesn’t have anything to
vibrate to make the noise in space.
Gizmo Warm-up
No sounds can be heard in outer space because sound waves
require a medium, such as air, to travel through. Sound waves
are examples of longitudinal waves, or waves in which
particles move back and forth in the same direction as the wave.
You can use the Longitudinal Waves Gizmo to explore the
behavior of sound waves. In the Gizmo, an air-filled tube
contains 24 evenly-spaced, airtight dividers. To begin, select the
Pulsed waves setting and the Open tube. Set the Strength to
1.00. Deselect the graph options at lower right.
1. Click Play ( ) to set off the firecracker by the left end of the tube. What do you see?
The wave moves left and right and then back. Also, it also dips below 0 on the second round
and every other one after.
2. Do any individual air molecules travel the length of the tube? I think they do.
How do you know? The airtight dividers didn’t block the air molecules from travelling
through.
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