Communication: Sound Communication

Question 1

explain that sound is produced by vibrating objects and that the frequency of the sound is the same as the frequency of the vibration of the source of the sound

Answer 1

Sound is a form of energy produced by an object that vibrates, moving backwards and forwards. The vibrating object causes nearby air molecules to vibrate back and forth, and these molecules cause others to vibrate.
This results in a compression wave travelling through the air.
The frequency of the vibration of air molecules is the same as the frequency of the vibrating object.

Question 2

outline the structure of the human larynx and the associated structures that assist the production of sound

Answer 2

Structures which assist in the production of sound are shown in the diagram below.
Structures that assist in the production of sound

The larynx or voice box lies directly below the tongue and soft palate. Inside the larynx are the vocal cords, which consist of muscles which can adjust pitch by altering their position and tension. Together, the larynx, tongue and hard and soft palate make speech possible. When air passes over the vocal cords in the larynx, they produce sounds that can be altered by the tongue, together with the hard and soft palate, the teeth and the lips.

Question 3

Relationship between wavelength and pitch.

Answer 3

Short wavelength waves have high frequencies and higher pitch. Long wavelength waves have low frequencies and lower pitch.

Question 4

gather and process information from secondary sources to outline and compare some of the structures used by animals to produce sound

Answer 4

Animal
Description of structure used to produce sound
bats

ultrasonic signals from the bat’s larynx

grasshoppers

friction of the back legs or rubs the veins on the wings together (stridulating)

frogs

male frogs vocalise by squeezing their lungs while shutting their nostrils and mouth, air flows over their vocal cords and into their vocal sacs

fish

some fish vibrate their swim bladders to create sound

Compare these structures. How are they similar? How are they different?
A useful starting point is the web site Biosonar (external website) University of Bristol, UK.

Animals use sounds for a variety of purposes. These include attack, escape, identification, warn off predators, mark territory, attract mates and for locating each other.

Secondary sources you could use include library books or the Internet. Good examples to look for include gulls, bees, dolphins, humpback whales and the great apes.

Question 5

explain why sound is a useful and versatile form of communication

Answer 5

Many animals use sound to communicate with each other. Sound is a versatile form of communication because animals can vary the nature of the sounds they produce. For example, animals may produce sounds of varying pitch and loudness to communicate different information.
Sound is also useful both day and night. It travels over long distances and can go around corners. The sender does not have to be visible to the receiver.