Infrared radiation is kinda like a special beam of light that we can't see with our eyes. It's part of a bigger group called electromagnetic radiation which includes things like visible light, radio waves, and X-rays.
Infrared radiation is special because it helps keep things warm. Think of it like a warm blanket for your body, except it can work on a lot of different things! Anything that gives off heat, like your warm cup of cocoa or your body when you're feeling hot, gives off infrared radiation.
Scientists use special cameras to "see" infrared radiation and they can use it to learn about things like how heat moves through a room or how some animals hunt at night even without being able to see in the dark.
So basically, infrared radiation is like a special beam of warm light that we can't see with our eyes, and it's very useful for helping us learn more about the world around us.