Refraction of Sound: Explanation

Introduction:
Sound is a form of energy that travels in the form of waves through different mediums. The speed of sound varies depending on various factors such as temperature, humidity, and wind conditions. One of the phenomena that affect the propagation of sound is refraction.

Definition of Refraction:
Refraction is the bending of sound waves as they pass from one medium to another due to a change in their speed. When sound waves enter a medium with a different density or temperature, they change their direction.

Refraction of Sound in the Atmosphere:
During the day, the temperature of the Earth's surface increases, leading to the heating of the air closest to the surface. This causes the air near the surface to be less dense compared to the higher layers of the atmosphere. As a result, the speed of sound in the lower layers of the atmosphere is lower than the speed of sound in the upper layers.

Explanation:
The phenomenon of refraction causes sound waves to bend towards the region of higher speed as they travel from one medium to another. In the case of sound traveling through the atmosphere, the sound waves tend to bend away from the surface of the Earth during the day.

This bending of sound waves away from the surface of the Earth during the day prevents the sound from reaching longer distances. The sound waves get reflected back towards the ground due to the change in medium and the bending effect. Hence, the sound is heard at shorter distances during the day.

However, during the night, the surface of the Earth cools down, causing the air near the surface to become denser. This leads to a reversal in the density gradient of the atmosphere. As a result, the sound waves tend to bend towards the surface of the Earth during the night.

Implication:
This bending effect allows sound waves to travel longer distances during the night. The sound waves refract towards the ground and follow a curved path, allowing them to reach distant locations. This is why sound is heard at longer distances during the night compared to the day.

Conclusion:
In conclusion, the phenomenon of refraction plays a significant role in the propagation of sound waves. During the day, the bending of sound waves away from the surface of the Earth limits the distance over which the sound can be heard. However, during the night, the bending of sound waves towards the surface of the Earth allows them to travel longer distances, resulting in sound being heard at greater distances.

Due to refraction, sound is heard at longer distances in nights than in day.