10.3 characteristics of a sound tide (ESADD)

Since sound is a wave, we deserve to relate the nature of sound come the properties of a wave. The straightforward properties of sound are: pitch, loudness and also tone.

You are watching: What factor determines the pitch of a sound


Figure 10.2: Pitch and also loudness the sound. Sound B has actually a lower pitch (lower frequency) 보다 Sound A and also is softer (smaller amplitude) than Sound C.


The frequency of a sound tide is what your ear understands together pitch. A greater frequency sound has actually a higher pitch, and also a reduced frequency sound has a lower pitch. In figure 10.2 sound A has a greater pitch 보다 sound B. Because that instance, the chirp that a bird would have a high pitch, yet the roar the a lion would have a short pitch.

The human being ear can detect a wide selection of frequencies. Frequencies indigenous 20 to 20 000 Hz room audible come the human being ear. Any kind of sound through a frequency below 20 Hz is known as an infrasound and also any sound through a frequency above ( ext20 000) ( extHz) is well-known as one ultrasound.

Table 10.2 list the ranges of part common pets compared come humans.

lower frequency (( extHz)) upper frequency (( extHz))
Humans ( ext20) ( ext20 000)
Dogs ( ext50) ( ext45 000)
Cats ( ext45) ( ext85 000)
Bats ( ext20) ( ext120 000)
Dolphins ( ext0,25) ( ext200 000)
Elephants ( ext5) ( ext10 000)

Table 10.2: range of frequencies

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Range the wavelengths

Using the information offered in Table 10.2, calculation the lower and upper wavelengths that each species can hear. I think the rate of sound in waiting is ( ext344) ( extm·s$^-1$).


The amplitude of a sound tide determines its loudness or volume. A larger amplitude means a larger sound, and a smaller sized amplitude means a softer sound. In number 10.2 sound C is louder 보다 sound B. The vibration the a source sets the amplitude that a wave. That transmits power into the tool through that is vibration. Much more energetic vibration corresponds to larger amplitude. The molecules move ago and forth an ext vigorously.

The loudness of a sound is also determined by the sensitivity the the ear. The human ear is much more sensitive to part frequencies 보다 to others. The volume us receive thus depends on both the amplitude the a sound wave and whether that is frequency lies in a an ar where the ear is an ext or much less sensitive.

Sound, frequency and also amplitude

Textbook practice 10.1

Study the adhering to diagram representing a music note. Redraw the diagram for a note

with a higher pitch

that is louder

that is softer


Solution not yet available

Comparing sound generating instruments

The size and shape that instruments impacts the sounds the they room able to produce. Find some tools that have different physical characteristics and also compare your sounds. You could:

Option 1: Vuvuzelas:

Compare the sound made through blowing with vuvuzelas of different sizes. Girlfriend will require to discover a few different vuvuzelas. Take transforms blowing the different ones, one at a time and also record which you think is louder (amplitude), i m sorry is of greater pitch (frequency).

Option 2: Tuning forks:

Compare the sounds developed by tapping tuning forks of different sizes.

You will need to uncover a couple of different tuning forks. Take transforms tapping the various ones, one in ~ a time and record which friend think is larger (amplitude), i m sorry is of higher pitch (frequency).

Option 3: Signal generator and also oscilloscope

Use a function generator associated to a speak to develop sounds of different frequencies and amplitudes and also use a microphone linked to one oscilloscope to display the characteristics of the different sounds produced.

Function generator

The function generator enables you to manage the loudness and also frequency the the sound being produced by the speaker. That will have controls for amplitude and frequency.

A duty generator



The microphone can then choose up the sound and convert it come an electrical signal which deserve to be presented on the oscilloscope.

The most usual oscilloscope controls room for amplitude, frequency, triggering, and channels. As soon as your teacher has actually helped you acquire a signal making use of the correct channel and also triggering girlfriend will use the amplitude and also frequency controls to screen the attributes of the sound gift produced.

The amplitude adjustment of an oscilloscope controls exactly how tall a offered voltage will appear on the screen. The function of this mediate is that you have the right to see a very huge or a very tiny signal top top the very same screen.

An oscilloscope


Two various oscilloscope traces


The frequency (or time) adjustment of an oscilloscope is how much time will certainly a specific distance throughout the display represent. The objective of this adjustment is to be able to see a an extremely quickly changing or a slowly changing signal top top the very same screen.

Note:The display of the oscilloscope will display you a transverse wave pattern. This walk not median that sound waves are transverse waves however just mirrors that the push being measure up is fluctuating due to the fact that of a pressure wave.

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You will be able to experiment with different amplitudes and frequencies making use of the duty generator and also see what impact the changes have top top the waveform picked up by the microphone.