Naked Science Forum
General Science => General Science => Topic started by: bizerl on 17/02/2013 23:08:28
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Okay, I wasn't sure how to condense this question into a snappy question, but what I'd like to know is that when we comb our hair, I have heard that the comb strips electrons off the atoms in the hair and then some other stuff happens and you get a shock when you touch the metal door frame.
How can electrons be stripped off something without changing the structure on an atomic scale? Is hair still "hair" after combing it?
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It seems I've found something of an answer on a similar post (http://www.thenakedscientists.com/forum/index.php?topic=46973.0).
Is static electricity any different?
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Hair is formed from a family of proteins called keratin, which is produced in a complex structure to form a single strand of hair.
Most of our bodies are filled with a conductive salt solution, so any electrical charge on a protein is quickly cancelled out by the surrounding water and damage is limited by antioxidant molecules. However, hair is dead, relatively dry and non-conductive, and so a static electric charge remains in place for a long period, allowing long hair to be attracted to the comb. (I am not sure what shampoo advertising means by "dry hair" and "moisturiser": I suspect that this has more to do with oils than water...)
On the atomic scale, a protein looks like this: http://en.wikipedia.org/wiki/File:Peptide-Figure-Revised.png
There are several places in this molecule where you could more easily rip off an electron without doing too much damage to the molecular structure.
Losing an electron makes the protein more susceptible to chemical attack. Even if this breaks an individual protein strand, adjacent strands of keratin protein are held together by sulfur bonds, giving it a structure which is very mechanically resilient.
So hair is still hair, even after combing it - just a little less knotted, and a little more sparky.
For more information:
http://en.wikipedia.org/wiki/Hair
http://en.wikipedia.org/wiki/Keratin
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How can electrons be stripped off something without changing the structure on an atomic scale? Is hair still "hair" after combing it?
First, stripping off electrons doesn't change the atoms - they still have the same number of protons, so retain their 'identity'.
Second, (I guess) the number of electrons lost will still be miniscule compared to the number of atoms in the hair so it does not overall have a significant effect on the chemical bonding/structure within the material (hair).