Topic # 6.4
GPS: 9e, f
Properties of Sound
Funsheet
Name: ______________________
Date: ___/____/____ Per: ___
PS
SPS9e Relate the speed of sound to different
mediums. SPS9f Explain the Doppler Effect
in terms of everyday interactions.
Directions: After reading sections 11.1 and 11.2 in your textbook, fill in the blanks below.
Section 1: The Nature of Sound
Section 2: The Properties of Sound
A. All sounds are caused by something that ______________.
A. The amount of energy a wave carries corresponds to its
1.
2.
_______________—formed when a vibrating object
_____________, which is related to the density of the
collides with air molecules, transferring energy to them
particles in the compressions and rarefactions.
Compressional waves have two regions, called
1.
compressions (H) and ________________ (G), which
_____________—the amount of energy that flows
through a certain area in a specific amount of time
push air molecules together and then spread them
2.
____________—human perception of sound intensity
apart.
3.
Each unit on a scale that measures sound intensity is a
_____________.
B. _________—how low or high a sound seems to be
1.
B. __________—the type of matter, whether liquid, solid, or
rarefactions of a sound wave that pass per second; human
gas; that sound waves travel through
1.
ears can hear frequencies from about 20 to 20,000 Hz.
A sound wave’s _________ depends on the substance of
2.
the medium and whether the medium is solid, liquid, or
3.
Sound travels more ___________ through solids and
Infrasonic or ____________ waves with frequencies below
20 Hz usually can’t be heard but may feel like a rumble.
liquids because the individual molecules are closer
3.
______________ waves are sound frequencies over
20,000 Hz that have medical and scientific uses.
gas. There is no sound in a vacuum (outer space)!
2.
_____________ is the number of compressions or
C.
___________ ________—change in pitch or wave frequency
together than the molecules in gas.
due to moving; either the source of the wave or the observer
As a medium’s _______________ increases, its
can be moving
molecules move faster and it conducts sound waves
faster.
Two cool Doppler Effect sims:
http://www.falstad.com/ripple/ex-doppler.html
http://www.walter-fendt.de/html5/phen/
dopplereffect_en.htm
Directions: Circle the term that correctly completes the sentence.
1.
Sound is produced by (vibrations, waves).
4.
The intensity of a sound is measured in (units, decibels).
2.
Sound travels faster in (liquids, solids).
5.
Sound waves can NOT move through (wood, a vacuum).
3.
Sound waves of (low, high) intensity travel farther.
6.
The speed of sound depends on the (temperature, empty space).
7.
A sound wave consists of compressions and (vibrations, rarefactions).
8.
Compressions and rarefactions are kinds of (sound waves, vibration waves).
9.
The amount of energy that flows through a certain area in a specific amount of time is known as (intensity, loudness).
10. Sources such as wind, earthquakes, and heavy machinery produce sound waves that vibrate (slowly, quickly).
11. A change in pitch or wave frequency due to movement is known as (the Doppler Effect, ultrasonic waves).
Directions: Answer the following questions about the Doppler Effect. Use Ch. 11 to help you.
1. The Doppler Effect can be defined as:
a.
The closer a sound-producing object gets to an observer, the (higher, lower) its frequency (meaning pitch) becomes.
Give 2 examples of moving sound-producing objects: ________________________ and ____________________________
b.
As this sound-producing object moves farther away from the observer, the (higher, lower) its frequency becomes.
2.
True or False? The Doppler Effect happens when either the source of the observer is moving. ____________
3.
As a police car moves towards a person, the frequency of its siren is 470 Hz. After the siren passes the person, the person hears
a sound with a frequency:
4.
higher than 470 Hz
equal to 470 Hz
The NMHS class-change bells ring with a musical note of middle C (256 Hz). A driver on Hwy 92/166 has the windows down and
hears what as he approaches NMHS?
5.
lower than 470 Hz
a note higher than 256 Hz
a note lower than 256 Hz
a note equal to 256 Hz
If the frequency of a police siren is recorded at 400 Hz and then recorded at 450 Hz a moment later, what most likely happened?
the siren moved away from the person
the person moved away from the siren
the siren moved towards the person
6.
Describe what you see in the two pictures below, using the words in the word box, along with some of your own. Be specific.
ambulance
observer
compression
increasing
decreasing
frequency
moving
pitch
__________________________________________________
_________________________________________________
__________________________________________________
_________________________________________________
__________________________________________________
_________________________________________________
__________________________________________________
_________________________________________________
Directions: Answer the following questions on the lines provided. Use Chapter 11 to help you.
1.
What causes sound? ______________________________________________________________________________________
2.
How do air molecules enable sound to travel from a radio’s speaker to your ears? _____________________________________
________________________________________________________________________________________________________
________________________________________________________________________________________________________
3.
Describe how the ringing sound of a telephone travels from the phone to your ear. ____________________________________
________________________________________________________________________________________________________
________________________________________________________________________________________________________
4.
Through which medium would sound travel the fastest, water, a steel bar, or nitrogen gas? Explain. ______________________
________________________________________________________________________________________________________
5.
In which medium would sound travel the fastest, water at 10°C or water at 25°C? Why? ________________________________
________________________________________________________________________________________________________
6.
What indicates the amplitude of a compressional wave? __________________________________________________________
________________________________________________________________________________________________________
7.
How are loudness and intensity related to the amplitude and energy of a sound wave? What is the unit of intensity? _________
________________________________________________________________________________________________________
________________________________________________________________________________________________________
8.
Describe how ultrasound and infrasound differ from normal sound, and give an example of each. _________________________
________________________________________________________________________________________________________
________________________________________________________________________________________________________
________________________________________________________________________________________________________
9.
What happens to the sound of a train whistle as the train approaches and then passes you? Why? ________________________
________________________________________________________________________________________________________
________________________________________________________________________________________________________
________________________________________________________________________________________________________
10. What does a hertz measure? ___________________________________________ What is the abbreviation for hertz? ________
11. What do decibels measure? _________________________________________ What is the abbreviation for decibels? ________