Lesson Objectives

1. Explore the concepts of sound wave, loudness of sound, amplitude, frequency and pitch.

2. Formulate the relationship between the loudness of the sound and the amplitude.

3. Investigate the relationship between the pitch of the sound and the frequency using tuning forks.​

Subject | Science

• Requires a Medium

• Cannot travel in a Vacuum

• Speed: Gas < Liquid < Solid

Propagation of Sound

The frequency of a wave is the number of wavelengths that pass through a point in one second. It is also described as the numbers of vibrations a body makes in one second. It is denoted by ‘f’.

It is measured in hertz (Hz).​

​Frequency

Amplitude is the measure of displacement of vibrating body on either side about its mean position.

Amplitude is measured in metre and generally denoted by ‘a’.

Greater the energy a wave carries, the larger is its amplitude​.

​Amplitude

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• A loud sound can be produced by striking the cymbals hard and a soft sound can be produced by striking them gently.​

• Loud sounds have more energy than soft sounds.

• The amount of energy that a wave carries across a unit area in each second is the intensity of the sound.

• The intensity of sound waves is related to the amplitude.

• The intensity of sound waves is measured in decibels (dB).​

​Loudness of Sound

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