Why do we yawn when we feel sleepy or tired?

We yawn when we feel sleepy or tired because our body is trying to wake up or relax more easily.

Imagine your brain is like a radio station that plays music all day long. When you're tired, the music gets quieter, and your brain needs a little boost to keep playing it clearly. A yawn is like turning up the volume on that radio, it helps your brain stay alert or get ready for sleep.

When you yawn, you take in more air, which makes your body feel refreshed. It's like taking a deep breath before jumping into a big puddle, it gets you ready for something new.

Also, when you yawn, your body relaxes a bit too. Think about how you stretch after sitting still for a long time, yawning is kind of like that, but for your whole body and brain.

Sometimes, people around you yawn too, and then you do it too. It's almost like a silly game where everyone joins in, and that makes the feeling of being sleepy or tired even stronger!