Browse Lessons
Assign Lesson

Help Teaching subscribers can assign lessons to their students to review online!

Assign Lesson to Students

Share/Like This Page

Reflection of Sound Waves

Reflection of Sound Waves

This lesson aligns with NGSS PS4.A

Our surroundings are filled with a variety of sounds that generate from different sources. However, have you ever pondered over how sound waves travel? Surprisingly, we can hear thunder rumbling from distant clouds in the stratosphere.  Just like the reflection of light, the reflection of sound is similar as it follows the laws of reflection. Reflection of sound is a natural phenomenon where sound waves encounter a barrier and bounce back within the same medium. This phenomenon is commonly observed in our daily lives. In this article, we will learn about the reflection of sound, echo, echolocation, and echolocation technology.

Reflection of Sound Waves
The phenomenon where a sound wave bounces back upon striking a solid surface is referred to as a reflection of sound waves. Let’s take an example, suppose we are seated in a vacant hall and engage in conversation, we hear an echo sound which is created by the reflection of sound. Some surfaces are excellent sound reflectors. When sound waves strike these surfaces, they bounce back and change their direction. This phenomenon leads to echoes.

An “echo” is the term used to describe the sound that is heard after sound waves reflect from a solid surface like a cliff or a wall. It is a repetition of sound even after the source has ceased vibrating.  The reflection of sound waves depends on the reflecting surfaces. Smooth, hard surfaces tend to provide the best reflection for sound waves. This explains why a shout in an empty gymnasium can produce an echo, while the same shout in an empty auditorium typically does not result in an echo.

Beluga whales use echoes to locate their food. This practice of utilizing reflected sound waves to find objects is known as “Echolocation”. Similar to beluga whales, other creatures like dolphins, bats, and other species of birds also rely on echolocation to hunt food and detect objects in their paths.

How does Echolocation work?
  • Bats emit ultrasonic waves as they are in flight.
  • When sound waves encounter an object, they bounce back to the bat. By measuring the time, it takes for the echoes to return, the bat can determine the distance to the obstacle.
  • The bat can identify an approaching insect due to the Doppler effect. In this case, the frequency of the echo will be higher than that of the original sound wave.

Sonar Technology
Humans utilize echoes to detect objects both underwater and underground through the application of sonar, which stands for “sound navigation and ranging.” Sonar is an electronic form of echolocation. Ultrasonic waves are used in sonar because their short wavelength offers more information about the reflected objects. This technology not only assists navigators on ships in detecting icebergs but also aids oceanographers in mapping the ocean floor.

Ultrasonography is another form of electronic echolocation that is used in medical procedure. Ultrasonography uses echoes that allow medical professionals to visualize the internal structures of a patient's body without performing surgery.A specialized device called a transducer is used to generate ultrasonic waves, which are directed toward the patient's internal organs. These waves then produce echoes as they bounce back from the organs. These echoes are converted into real-time images, which can be observed on a television monitor, as depicted in Figure.

Ultrasonography serves various medical purposes, including the examination of kidneys, gallbladders, and other abdominal organs, and to check the development of an unborn baby inside a mother's womb. This technology is considered safer than X-rays because sound waves are less harmful to human tissue.

  • Reflection of sound waves occurs when sound waves encounter a barrier and bounce back toward their source. Reflected sound waves are heard as an echo.
  • Echolocation is a practice that utilizes the reflected sound to locate objects. Dolphins, bats, and other specific birds use echolocation to hunt their food.
  • In Sonar technology, ultrasonic waves are used to explore detailed information about the reflected objects.
  • Ultrasonography is another type of electronic echolocation that is used to visualize the internal structure of a patient’s body without performing surgery.

Related Worksheets:

Become a Help Teaching Pro subscriber to access premium lessons

Unlimited premium lessons Unlimited premium printables Unlimited online testing

Learn More About Benefits and Options