How do noise-cancelling headphones eliminate sound?

Noise-cancelling headphones are like having a special kind of ear shield that stops annoying sounds from reaching your ears.

Imagine you're in a loud room full of people talking and a vacuum cleaner going at the same time. That's like being on an airplane or in a busy café. Now, imagine wearing a pair of headphones that can sense those sounds and create their own opposite sound to cancel them out, just like when you whisper to someone and they whisper back so no one else can hear you.

Noise-cancelling headphones have tiny microphones inside them. These microphones listen to the annoying sounds around you, like airplane engines or loud music. Then, a little computer chip inside the headphones quickly creates a sound that’s exactly the opposite of what it hears, this is called opposite sound waves.

When the annoying sound and the opposite sound meet in your ear, they cancel each other out, just like when two waves in the ocean meet and make a calm spot. That means you hear less noise, or maybe even none at all!