Why do we get goosebumps when we're cold?

We get goosebumps when we're cold because our body is trying to stay warm.

Imagine your skin is like a blanket. When you're cold, your body wants to keep the heat in, so it sends little hairs on your arms and legs standing up, kind of like how a blanket fluffs up to trap more warmth. These hairs are like tiny little blankets that help hold onto the heat.

When you're cold, your skin gets a little message from your brain: "We need more warmth!" So it tells all the little hairs on your arms and legs to stand up. That’s what makes the goosebumps, they look like tiny bumps because of the hairs standing up.

It's similar to when you wear a sweater that’s too big, and you pull it over your head, the fabric bunches up in little bumps, just like your skin does when you're cold.