Reflection of Sound for Class 9: Understand How Sound Reflects Like Light

Reflection of Sound is the bouncing back of sound when it hits a surface. We often hear echoes or sounds coming back to us, and this happens due to reflection. Sound behaves in a way similar to light when it strikes a surface. Sound behaves in a way similar to light when it strikes a surface. It follows certain rules while reflecting

This article is a perfect guide to understand what is reflection of sound and the laws that it follows while reflecting back.

Table of Contents

• What is the Reflection of Sound?
• Laws of Reflection of Sound

What is the Reflection of Sound?

Sound bounces off a solid or a liquid surface just like a rubber ball bounces off a wall. When sound strikes a surface, it gets reflected back into the same medium.

Have you ever noticed that when you shout near a wall or in a large hall, you can hear your own voice coming back? This happens because sound waves hit the surface and return to you after reflection.

Now, you may ask, do sounds follow any rules while reflecting?

The fact is, sound follows the same laws of reflection as light. For reflection to occur properly, the surface should be large enough. It can be smooth or even rough.

To see how this happens in real life, let’s perform a simple activity.

Activity 

Aim: To observe the reflection of sound and verify its laws. Materials Required: Two identical pipes, chart paper, a clock or a mobile phone (vibration mode), and a wall Diagram: Procedure: Take two identical pipes and place them on a table near a wall. Keep a clock near the open end of one pipe and try to hear the sound through the other pipe. Now adjust the position of the pipes until the sound is heard clearly. Measure the angles of incidence and reflection and observe their relationship. Lift one pipe slightly upward and observe what happens. Observation:  The sound is heard clearly only at a particular position. Conclusion: The angle of incidence is equal to the angle of reflection.

Now, the obvious question is: what does this activity show?

The fact is, this activity proves that sound follows certain definite laws while reflecting.

Laws of Reflection of Sound

There are two main laws:

• The angle of incidence is equal to the angle of reflection.

• The incident sound, the reflected sound, and the normal at the point of incidence all lie in the same plane.

So, in simple words, sound reflects in a regular and predictable way, just like light.

In this article, we learned that reflection of sound is the bouncing back of sound from a surface. We also understood that sound follows definite laws while reflecting, just like light. The activity showed that the angle of incidence is equal to the angle of reflection, and all directions lie in the same plane.