Name:___________________ Class:_____
Sound Travel
Learning Target: I can explain how sound travels
through different types of matter. I can compare
and contrast sound travel through a solid and a gas.
Sound can travel through all four phases of matter: _____________,
________________, _________________, and _________________.
However, the type of medium that sound is traveling through determines
how fast it travels. Sound travels fastest through a ___________
because the molecules are ___________________________. Sound
travels slower through a liquid and even slower through a gas or plasma..
Doppler Effect:
Did you ever notice that when a siren moves towards you it sounds higher
pitched and as it moves away the pitch gets lower? The higher pitch is the
result of the Doppler effect. In a moving sound source, the sound waves
are moving in the same direction as the source as they approach the
listener. This makes the compressions and rarefactions closer together.
As the car passes and travels away, the sound waves move in an opposite
direction of the car, and they sound lower in pitch. However, the driver is
moving with the car and therefore always hears the same pitch.
Draw a picture of what the Doppler effect looks like in a moving police car:
Remember:

Particles in a solid are close together, so they can pass sound faster.

Particles in a gas are farther apart, so they pass sound more slowly.
Draw pictures of particles in a solid, liquid and gas in the boxes below:
Interactions of Sound Waves
The bouncing back of a sound wave after it strikes a barrier is a
reflection. Did you ever notice how an empty room causes echoes? When a
sound bounces back off of a flat surface it reflects, which causes an
_________________. In order to prevent echoes, auditoriums and
recording studios often have material to absorb the sound.
Interference of Sound Waves
Sound waves interact through interference.
Constructive Interference: When several instruments of the same kind
play the same note. The compressions of one wave overlap the
________________ of another wave
Temperature
Temperature also affects the speed of sound.

Colder temperature _______________ sound down.

Hotter temperature ________________ sound up.
Destructive Interference: When waves reflect off of walls in an room and
interfere with the sound. The compressions of one wave overlap the
__________________ of another wave.
Draw a picture of constructive interference:
5. If two sound waves interfere constructively, you will hear
A. a high-pitched sound B. a softer sound C. a louder sound D. no change
Draw a picture of destructive interference:
What is a standing wave? A pattern of _______________ that looks like
a wave is standing still.
Example: A guitar string after you have plucked it. It is vibrating but it
looks like it is standing still. Draw a standing wave below:
Resonance: a phenomenon that occurs when two objects naturally
_______________ at the same ____________________. The sound
produced by one object causes the other object to vibrate.
Resonance: musical instruments use resonance to generate sounds. An
acoustic guitar has a hollow body that amplifies the sounds.
1.
The _________________ of a sound wave depends on its amplitude.
2. Reflected sound waves are called _______________.
3. If a fire engine is traveling toward you, the Doppler effect will cause
the siren to sound ________________.
4. Sound travels fastest through __________________.
6. Resonance can happen when an object vibrates at another object’s
A. resonant frequency
B. fundamental frequency
C. Second overtone frequency
D. Third overtone frequency
Use the space below to compare/contrast transverse and longitudinal
waves: