Re: How does drain cleaner dissolve hair?

Dear Doug,

Good idea for a science fair project!

There are three things that need to be addressed in order to answer your question. First, what is hair made of? Second, what chemical(s) in "drain cleaner" is responsible for dissolving hair? Third what chemical reactions took place in order for the hair to be dissolved?

What is hair made of? The answer is that hair is composed, primarily, of a protein termed keratin. So, you are correct that keratin is important to your experiment. For detailed descriptions of the composition of hair see these other pages on MadSci Network:

http: //www.madsci.org/posts/archives/may98/892764277.Ch.r.html

(which describes the chemical reactions that take place when someone gets a "permanent")
and http: //www.madsci.org/posts/archives/jun99/928507693.Bc.r.html

What chemical(s) in the drain cleaner is responsible for dissolving hair? The answer to this depends on the type of drain cleaner that you used. There are four general classes of drain cleaners: acids, oxidizers, caustics and enzymatic cleaners. There is a good description of each of these at the following web site:
http://www.mcs.net/~merid ian/draincle.html

What happened to make the hair dissolve? The previous link to the web page that describes the classes of drain cleaners also has a detailed section that describes the chemical action of each class.

On a less serious note (unless you are one of the unfortunate individuals to whom the following has occurred), if you wash your dog in the shower (or bath tub), the build-up of dog hair in the drain and plumbing can result in the production of a foul smell. Here is the link to the question:

http: //www.madsci.org/posts/archives/aug98/902622760.Ch.q.html

and to the response:
http: //www.madsci.org/posts/archives/aug98/902622760.Ch.r.html

So, if you have a dog, you may want to wash him/her outside on the yard!

Finally, be careful when you are handling the drain cleaner. Most drain cleaners are strong irritants that can damage your skin and eyes.

Good luck with your project.

Sincerely,
Kevin K. Caldwell
University of New Mexico