The amount of sound we hear daily is immense, from the sound of running water to music or moving vehicles. 

Sound waves

Sound is essentially the reception of sound waves, which are vibrations traveling through a medium like air, water, or solids. These waves are captured by receptors in our ears, converted in signals, and sent to the brain. 

The brain filters the immense amount of sound waves to help us focus on specific sounds. Click here to understand the process in the brain.

Illustration balloon

Sound waves are a form of energy transferred through a medium. To understand this, imagine a balloon. Inside the ballon, the air particles are under pressure. When the ballon pops, the high-pressure air inside hits the surrounding air particles, transferring their energy to them. 

This creates an expanding shell of air particles just bouncing into one another until they eventually apply a force to your ear. The energy causes parts of your inner ear to move. 

These movements are interpreted by your brain, which recognizes the sound-like the pop of the balloon.

But why are they called waves? And where does this wave-like pattern come from?

Compressions and Rarefactions

When the high-pressure air from the popped balloon rushes out, it creates a high-pressure region- a compression. This is followed by a low-reassure void as air particles rush back to fill the space, creating a rarefaction. 

This cycle of compression and rarefaction repeats, forming a wave pattern that can be graphed.

The high points are compressions, where air particles are compressed and densely packed. The low points are rarefactions, where air particles more spread out.

Traveling sound waves

Although it might seem like the particles themselves travel with the wave, this is not the case. Instead, it is the energy or force being transferred through the particles. 

For example, when we speak or turn on a loudspeaker, we convert kinetic energy on the particles in the air that pushes them back and forth. This energy propagates through air as sound waves, eventually reaching a sound receiver, like your ear.

Do not conduse sound waves with electromagnetic waves.