Saturday, February 25, 2012

How fast does hair grow?

According to wikipedia, the answer is about 1.25 cm/month (or 0.5 inch/month), however yesterday I found out a nicer way to express this speed :)
Sheldon Cooper (The Big Bang Theory - Episode 5x18, link below) claims that is 4.6 yoctometers per femtosecond (so 1.2 cm per month or 0.47 inches per month).

Interesting how you can use two very small scales (1 yoctometer = 10^-24 meter and 1 femtosecond = 10^-15 s) to express such an everyday-life-thing as the hair growth!

On the scale of yoctometers, a proton is gigantic! Indeed a proton is 10^-15 meters so 1 billions of yoctometers!
Femtoseconds are bit more close to our everyday common sense, for example the visible light waves oscillate on the femtosecond scale (for a wavelength of 580 nm the corresponding period is 1.93 fs).

Concerning the length scales of the incredibly small and incredible big things, I recommend you these nice pages

The Scale of the Universe
The Scale of the Universe 2

By the way, here is the original scene from The Big Bang Theory...enjoy!

Other fun facts on this blog

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nancy john said...

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eddie said...


Anonymous said...
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Anonymous said...

This is fantastic!!! Only just discovered it and can´t get enough watching, clicking and wondering... Thanks a million for this great link!
Sylvia again

eddie said...

Ciao Sylvia!
You're welcome!

Henry Psanec said...

Hello. This is a very fine place and this is a very fine article! To the best of my knowledge it had been the only place with Sheldon and yoctometers until a few seconds away when I used your article to reference a newly added section in the Wikipedia Yocto- article. Have a nice weekend!

eddie said...

Thanks Henry, that's very kind from you!
I also wish you a nice weekend and keep following my blog ;)