Firmament

The firmament is a big word that people use to talk about the sky above our heads. It's like a big dome that covers the earth and separates us from the things outside of it.

Think of the firmament like a big, invisible ceiling above us, like the roof of your house. Just like your roof keeps you safe from the rain and other things outside, the firmament protects us from things in space, like the sun, stars, and other planets.

The firmament is also sometimes called the heavens, and people have been looking up at it for a really long time. In fact, some people used to believe that the firmament was made of a solid material, like glass or crystal. But we now know that it's just the atmosphere that surrounds our planet.

So, the firmament is the sky above us that protects us from things in space, and we can see it whenever we look up at it.