Human body Episode 2 · October 28, 2026
Why Doesn’t a Haircut Hurt?
Plays from YouTube in privacy-enhanced mode.
The big question
How do your hair and nails grow? And why doesn’t a haircut hurt?
Why doesn’t a haircut hurt? Pip the puffin zooms into your skin to see how hair and nails grow, what keratin is, and why the part you cut is already dead.
Words to know
keratin
Say it: KAIR-uh-tin
The tough stuff that hair, fingernails and toenails are made of. Pip’s beak and feathers, cat claws and rhino horns are keratin too!
Your fingernails are made of keratin.
mitosis
Say it: my-TOH-sis
When a living cell splits in two to make new cells. Deep in your skin, mitosis makes the new cells that grow your hair and nails.
Cells at the bottom of a hair split again and again.
follicle
Say it: FOL-ih-kul
The tiny tunnel in your skin that a hair grows out of. Round follicles make straight hair, and flat, oval ones make curls.
Every hair on your head has its own follicle.
anagen
Say it: AN-uh-jen
The growing time in a hair’s life. On your head it can last two to seven years before the hair rests and falls out.
Long hair is hair that has been in anagen for years.
matrix
Say it: MAY-triks
The hidden nail factory tucked under the skin at the bottom of your nail. It makes the new cells that push your nail forward.
The white half-moon on your nail is the part of the matrix you can see.
Bonus words: lunula, melanin, catagen, telogen, papilla
Quiz time!
Try it at home: Watch your nail grow
⏱ 2 minutes, then a few weeks
You need
- A grown-up
- A tiny dot of nail polish or a washable marker
- A ruler
Steps
- With a grown-up, put a tiny dot on one fingernail, right at the bottom where the nail comes out of the skin.
- Measure how far the dot is from the bottom of the nail. Write it down with the date.
- Measure again every week. (Marker washes off, so touch up the same spot. Nail polish lasts longer.)
- After a month, how far did the dot travel?
What’s going on? Fingernails grow about 3 and a half millimeters a month, so your dot should creep up a little each week. Toenails grow only about half as fast!
⚠️ Ask a grown-up before using nail polish.