How does noise-cancelling technology effectively block out sound?

Sound-cancelling technology is like having a special friend who helps you ignore loud noises.

When you're wearing headphones that cancel noise, they do something clever with sound waves. Think of sound waves as ripples in water, when you drop a stone into a pond, it makes waves. In the same way, sounds make waves in the air around us.

Headphones use microphones to listen to the noise around you, like the rumble of a plane or the chatter in a room. Then they send that sound to a tiny computer inside the headphones. This computer makes a copy of the sound, but it flips it upside down, like turning a wave into a hill instead of a valley.

Then the headphones play this flipped version of the noise right into your ears at exactly the same time as the real noise. When these two sounds meet, they cancel each other out, just like when you have two waves that go up and down at the same time, they can make a calm surface again.

It's like having a friend whisper the opposite of what someone else is saying so you don’t hear them anymore!