Expansion spring

Hey kiddo, do you remember those toys that you can stretch out and then they snap back into their original shape? That's kind of like what an expansion spring does!

An expansion spring is a long, coiled piece of metal that can stretch out when you pull on it. It's kind of like a Slinky, but instead of just being fun to play with, it has a special purpose.

This type of spring is often used in things like garage doors or screen doors. When you pull on the door to open it, the springs inside help to counterbalance the weight of the door so it's easier to lift. That's why sometimes you can open a heavy door with just one finger!

The way an expansion spring works is pretty cool. When it's coiled up, all the loops of metal are touching each other like a big springy hug. But when you stretch it out, those loops start to separate from each other, which makes the spring longer. When you let go, the loops all snap back into place and the spring becomes shorter again.

So basically, an expansion spring is just like a stretching toy, but it's used to make doors and other heavy objects easier to open and close. Pretty neat, huh?