Mains hum

Ok kiddo, so sometimes when you plug things into the wall like a lamp or a TV, you might hear a buzzing sound. That buzzing sound is called mains hum. It happens because the electricity that comes out of the wall is not perfect, and it has some extra stuff in it called "interference" that can make things vibrate or buzz.

Just like when you blow air out of your mouth and it makes a sound, the electricity in the wall makes a sound too! But instead of air, it's electricity that makes the sound.

Now, sometimes you can fix the problem of mains hum by using something called a "grounding wire." You know why that works? Because the extra interference in the electricity needs somewhere to go, and if you connect a wire from your device to the ground (like a big metal pipe that goes into the Earth), then the interference has a place to go and it won't make your device buzz anymore!

So don't worry, little one, mains hum is just a little problem that can be fixed with some simple wiring. And now you know a bit more about how electricity works!