Difference Between Radio Waves and Sound Waves

The music from our radios, the texts we send, and the calls we make are all the results of radio waves and sound waves. But don’t mistake one for another. They are different in all aspects: frequency, speed, source, wavelength, and applications.

Now, touch your throat when you are speaking. Can you feel the vibration? That is what creates sound waves – a moving object. But you can’t hear, see, or feel radio waves. They come from moving charged particles.

You will find more interesting details about the difference between radio waves and sound waves in this article.

How Do Radio Waves Differ From Sound Waves


Your FM radio has a lot to tell about the main difference between sound waves vs radio waves.

FM radios have many frequency channels, each one is monitored by a station. A transmitter converts the station’s content into radio waves and sends them into the atmosphere.

When you tune in to your favorite channel, your radio’s antenna catches the radio waves. Then, the speaker vibrates at the same amplitude and frequency as the signals received, generating sound waves so that you can listen to the content.

In technical details, how does a radio wave differ from a sound wave?

1. Frequency

The frequency of radio waves is from 300 GHz to 3 kHz, which we can’t hear but is ideal for sending signals. The frequency of sound waves is from 20 Hz to 20,000 Hz, which are audible to our ears.

This video will tell you more about the speed of sound and how it travels:

In still air, a male human voice can spread 180 meters at maximum, but you can talk to someone afar with radio waves. Similar to the radio, when you make a phone call, the transmitter in your phone converts your voice into radio waves and sends it to a network. Then, the network transmits it to the receiver’s phone. This erases any communication limits.

2. Speed

Radio waves travel at the speed of light – 300,000,000 meters per second, while sound travels at 343 meters per second. This means that in the time sound travels the length of a football field, radio waves can travel more than three rounds around the world.

The speed of radio waves allows you to hear the other person on a phone call almost immediately despite the distances.

3. Source

Radio waves are emitted by lightning and astronomical phenomena. But scientists can produce them artificially with time-varying electric currents. These currents consist of electrons constantly moving in a specially-shaped metal conductor, also known as an antenna.

Sound waves are created by a vibrating object. The vibrational motions can happen to air, water, or solid. It is the vibration of your throat while speaking or a monitor while playing music that generates sound. Additionally, natural phenomena can produce sound waves, such as lightning.

4. How the waves travel

Besides the speed, radio waves inherit another characteristic of light waves: they travel in a vacuum. In the atmosphere, radio waves spread at nearly that same speed, but they slow down when encountering obstacles.

Sound waves only travel through a medium. In space, you won’t hear any sound. When astronauts are spacewalking, they must communicate via headsets (that use radio waves) even though they are one meter away from each other.

Nonetheless, both waves play irreplaceable roles in our daily life.

Applications of Sound Waves

Sound waves help us create music, talk, listen to the radio, hear bird songs, and notice danger signals. They also have these applications.

1. Sonar

In the water, sound waves travel farther and smoother than radio and light waves. Thus, it helps us explore the ocean, locate fish, and measure depth; the technique is called sonar (short for sound navigation and ranging).

It works by sending out sound waves and measuring the time it takes for the echo to return. Dolphins, bats, and whales also communicate and detect obstacles with sonar.

2. Ultrasound imaging

By scanning a body part with ultrasound, doctors can receive images of the internal organs. Ultrasound imaging is noninvasive, painless, and time-saving. It is a huge step in medical advancement.

3. Cutting

Researchers at the University of Michigan are developing a surgical instrument that cuts using sound pressure. The instrument can focus on micro areas that are merely 75 micrometers, which is smaller than the thickness of a paper.

Applications of Radio Waves

Radio waves help transmit data in radio, cellular, wifi, and mobile networks. As you’re browsing the web, your device constantly transmits radio waves to your wifi router via frequencies. But their applications don’t stop there.

1. Radar

Radar uses radio waves to detect obstacles. Its antenna sends the waves into the environment and its receiver collects the reflected waves. Then, the radar calculates the waves’ speed and reflecting time to identify the obstacle’s position. Now, you know how your robot vacuum never crashes into the wall.

2. Space exploration

Since radio waves can travel in a vacuum, astronomers use them to communicate between aircraft and the Earth, detect astronomical phenomena, and transmit data into space.


Though we cannot see radio and sound waves with human eyes, they are everywhere around us. Understanding the difference between radio waves and sound waves will help us discover more of the unknown, so don’t hesitate to share this information with others.

Scientists are experimenting with stimulating clouds with low-frequency sound waves. So, before you leave, let me just ask you one more question. Do you believe we will be able to control the amount of rainfall on Earth one day?

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