Sound

Question 1

What is sound

Answer 1

Sound is a form of energy that is transferred from one point to another as a longitudinal wave

Question 2

How is sound produced

Answer 2

Sound is produced by vibrating sources placed in a medium

Question 3

How does a sound wave propagate

Answer 3

• The vibrating tuning fork displaces the molecules of the medium around it, which in turn displaced their neighboring molecules
• Sound waves propagate as a series of compressions and rarefractions
  *Compressions are regions where the medium’s density is higher than the surrounding density
  *Rarefractions are regions where the medium’s density is lower than the surrounding density

Question 4

Process of sound wave propagating

Answer 4

1. Layers of air are in undisturbed positions
2. When the prongs push outwards, a region of compression is produced
3. When the prongs move inwards, a region of rarefraction is produced
4. The prongs continue to vibrate and a series of compressions and rarefractions is set up

Question 5

Can sound travel through a vacuum

Answer 5

No. Sound requires a medium to travel from one point to another

Question 6

Speed of sound in mediums

Answer 6

Sound travels at different speeds in different mediums

Speed of sound: Gas < Liquid < Solid

Question 7

What is an echo

Answer 7

An echo is the repetition of a sound due to the reflection of sound

Question 8

What is ultrasound

Answer 8

Ultrasound is sound with frequencies above the upper limit of the human range of audibility

Question 9

Uses of ultrasound (Quality control)

Answer 9

-Ultrasound can be used to check for cracks and cavities in concrete slabs and metal pipes

1. Transmitter emits ultrasound
2. Ultrasound passes through the concrete and is received by a sensor
3. The presence and location of defects are indentified by comparing the ultrasound emitted with the ultrasound received

Question 10

Uses of ultrasound (Prenatal scanning)

Answer 10

-Ultrasound can be to obtain images of structures in the body

-It is used, instead of x-rays, to examine the development of foetuses because it does not harm the foetus

Question 11

What is pitch

Answer 11

Pitch is related to the frequency of a sound wave. The higher the frequency, the higher the pitch

Question 12

What is loudness

Answer 12

Loudness is related to the amplitude of a sound wave. The larger the amplitude, the louder the sound