NAME: ___________________________ GRADE: 7 DATE: __________
SUBJECT: Physics Topic: Sound Teacher’s sign_______________
Fill in the blanks with the words given below.
1. Describe how sound is transmitted.
Sound is a form of ______________ that is transferred from one point to another
by the ______________ of particles. As sound is a ___________ wave, the direction
of ________________of the particles is parallel to the direction of propagation of
the wave.
2. As sound is propagated by the vibration of particles, sound requires a
medium to travel. Unlike light, sound cannot travel in ______________.
3. The speed of sound is dependent on the medium it travels in. The
__________ the atoms in the medium, the faster the sound.
4. Speed of sound in air is ___________ m/s while speed of sound in water is
approximately ___________ m/s. As the particles in a metal are very _________,
the speed of sound in metals is approximately ______________.
5._____________is the number of complete waves or vibrations that go past a
particular point each second. The pitch of a sound depends on the frequency
of the vibrations that cause it. If there are _________of vibrations per
____________, the frequency is _____________ and the sound has a high pitch,
which is like a ___________ talking. If there are fewer (less) vibrations per
second, the frequency is _________________ and the sound has a low pitch.
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6a. Redraw the sound wave below with double the amplitude and twice frequency.
b. How will these changes affect the sound you hear?
___________________________________________________________________________
c. How many full waves are shown on the oscilloscope screen above.
_____________________________________________________________________________
7. Define the term echo.
_____________________________________________________________________________
8. State one use of ultrasound.
________________________________________________________________________________
9. What is the pitch of a sound wave related to?
________________________________________________________________________________
10. What is the loudness of a sound wave related to?
________________________________________________________________________________
2
A ship’s echo sounder transmits a pulse of sound. It is then reflected
back to the ship by a shoal of fish to a receiver 0.2 s later. If the shoal of
fish is 120 cm below the ship, what is the speed of the sound in water?
15. Which wave diagram has both wavelength (k) and amplitude (A)
labeled correctly?
16. An electric guitar is generating a sound of constant frequency. An
increase in which sound wave characteristic would result in an increase
in loudness? ANSWER: (4) amplitude
19. In which type of wave is the disturbance parallel to the direction of
wave travel? ANSWER: (2) longitudinal
If the frequency of a sound wave in air remains constant, its energy can
be varied by changing its ANSWER: (1) amplitude
Which form(s) of energy can be transmitted through a vacuum?
ANSWER: (1) light, only
4. Label the parts of the ear.
3
5. Match the correct anwser.
4
1. When an object vibrates it creates a sound wave. How quickly the object
vibrates changes the sound
5
a. How is the vibration creating trace A different from the vibration creating
trace B? b. How can you tell from the traces?
How is the vibration causing the loud trace different from the vibration
causing the quiet trace?
