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Postby ky2u2o » Mon Oct 18, 2010 11:23 pm

Last edited by ky2u2o on Tue Feb 22, 2011 11:46 pm, edited 1 time in total.

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Posts: 932
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Re: Experimenting with toothpaste

Postby barretttomlinson » Tue Feb 22, 2011 11:49 pm


I have no direct knowledge of your question and as far as I can tell a similar question has never been posed to the Ask an Expert blog. Doing a limited Google search and some poking around I suspect if anyone has studied it it was probably someone working for Proctor & Gamble at their Health Care Research Center in Mason, Ohio. Here is an abstract of one of their papers that leads me to think this: ... stractPlus

As to your other questions:
This sounds like it could be a very good (and probably original) research project, and might be within your technical abilities, though you and your teacher are far better judges of this than I. What is clear is that you would really benefit from having a mentor who knows something about this field. See this link on finding a mentor: ... tors.shtml

You may also find this page to have helpful information: ... ndex.shtml

I think your idea of an agar experiment has a chance of working, though most of the analogous experiments I am aware of have formed precipitates or grown crystals in agar rather than dissolved preexisting crystals, or they have measured bacterial growth inhibition by antibiotics diffusing out from a well or tab. If your experiment is to work I suspect you will have to suspend extremely small calcium phosphate crystals in the agar and diffuse out the toothpaste for quite a while(days?) to see it work.

This sounds like a really interesting project. I would encourage you to attempt it. Even if your experiment does not work the way you envision it you will learn a great deal and probably have fun. Go for it!

If you decide you want to look into another project idea, one I like that is experimentally similar to your idea is the formation of liesegang rings or bands:

You can also find great ideas using the Science Buddies Project Idea Guide (for link click on the name at the top of the page).

Whatever you decide to do, have fun with it!! Chemistry can be such a blast!

Best regards,

Barrett L Tomlinson

Last bumped by ky2u2o on Tue Feb 22, 2011 11:49 pm.

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