Okay kiddo, so imagine you have a big group of friends at school, but you only like to hang out with the ones who agree with everything you say and do. You don't really listen to what the other kids have to say because they don't think the same way as you. That's sort of what a media echo chamber is.
Instead of friends, it's people on the internet, on TV or in newspapers who all have similar opinions and beliefs. They keep sharing the same things over and over again, which means you hear the same ideas and thoughts all the time. It's like being in a room with a lot of mirrors. Every time you say something, the sound bounces back at you and gets louder and louder.
This can be a problem because you might not get a chance to hear a different point of view or learn something new. You might think your ideas are the only right ones because you don't hear anything that contradicts them. And that's not a good thing.
So, it's important to make sure you're hearing from a variety of sources, even if you don't agree with them. That will help you learn and grow and have a better understanding of the world around you.