Reflection, Refraction, And Diffraction of Sound Waves - SS3 Physics Lesson Note

Sound waves can exhibit several different behaviours as they travel through different mediums or encounter obstacles. These behaviours include reflection, refraction, and diffraction.

Reflection:

When a sound wave encounters a surface, some of the sounds may bounce back in the opposite direction. This is known as reflection and is what is normally heard as an echo. The angle at which the sound wave hits the surface (the angle of incidence) and the angle at which it reflects (the angle of reflection) obey the law of reflection, which states that the angle of incidence is equal to the angle of reflection. Reflection of sound waves is important in many practical applications, such as echolocation and soundproofing.

Refraction:

When a sound wave passes from one medium to another, its speed and direction can change. This is known as refraction. The degree to which the sound wave bends depends on the difference in the speed of sound between the two mediums, as well as the angle at which the sound wave enters the new medium. Refraction of sound waves is important in many applications, such as in the design of lenses and in the study of atmospheric acoustics.

Diffraction: 

When a sound wave encounters an obstacle, it may bend around the edges of the obstacle and spread out into the region behind it. This is known as diffraction. The degree to which a sound wave diffracts depends on the wavelength of the sound wave and the size of the obstacle. Diffraction of sound waves is important in many applications, such as in the design of concert halls and in the study of the effects of obstacles on sound propagation.

Understanding the behaviours of sound waves, including reflection, refraction, and diffraction, is important in many fields, including acoustics, engineering, and communication.