Easy as pie explained

Why does my hair stand on end?

When the hair "flies", it looks very funny.

(Bild: stock.adobe.com/Татьяна Кутина)

If you observe your body, you will notice that funny phenomena sometimes occur. Interested boys and girls can read below to find out why the hair on your arms stands up when you're scared and why the hair on your head "flies" when you take off your sweater. According to the motto: Explained child's play.

Sometimes your hair stands on end when you are frightened or very surprised. This happens because the body reacts in a special way. Imagine, for example, that you suddenly see a large dog running towards you. Your body thinks that danger is probably imminent and prepares itself for it.

It sends a signal to the small muscles "under" your hair roots, which then contract. This causes the hairs (on your arms, for example) to stand up and look as if they are standing on end. Some people also refer to this as "goose bumps".

Reaction of our ancestors
We have inherited this reaction from our ancestors: people used to live in a much more dangerous environment than they do today - with wild animals! When our ancestors were afraid or felt attacked, their hair stood up to make them look bigger and more threatening. This was a good deterrent to potential enemies.

Although we no longer live in the wild today, we still react in the same way as we did back then (even if not always to the same extent) because the process is deeply rooted in our genes. This is a fascinating example of how our bodies react instinctively. In the animal kingdom, this standing up of hair can still be observed today, for example as a threatening gesture in dogs or cats.

Standing hair
However, sometimes the hair on your head stands on end and "flies" when you take off a turtleneck sweater, for example. This is again due to physics: the sweater rubs against your body and your hair. The friction causes small electrical particles to form. These can jump from your body to the sweater or vice versa. This in turn creates an electrical charge.

Equal electrical charges repel each other. This is why your hair 'flies' because it moves away from each other. Sometimes you even hear a crackling sound or notice small sparks. This is how you experience a physical phenomenon. If you want to actively experiment, you can also rub a balloon against your sweater and then hold it up to your head. Your hair will stand out quite clearly. Have fun trying it out!