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Science fair project for a 5th grader

My son, Ammon, is doing a science fair project. I am a general contractor and we use muriatic acid for cleaning masonry. I have a gallon of muriatic acid, and my son wants to see what it will do to different kinds of materials. I am just wondering if anybody would have any suggestions that would make Ammon's experiments real interesting and informative for 5th graders. We are following all the safety guide lines using acid. Thank you for any help.

Carl T. [surname deleted for privacy by Editor]
Student/Contractor - North Ogden, Utah
2003

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I'm sure you're following the guidelines, but on science fair night, unless your school is different than where my kids went, everything you can think of will be thrown into the vat until finally some kid knocks it over :-)

So I would recommend that he display his findings rather than the vat of acid.

I would try putting simple repeatable everyday metal things like aluminum and brass key blanks, and pennies and nickels into the acid for short but controlled periods.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

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I'd second Ted's comments about everyday items, and you may also want to vary the finishes. Rough vs. smooth, for instance, seeing which one corrodes faster. I'd avoid anything porous like wood or paper that might absorb the acid. A scratched penny would be cool, as the muriatic would really go after the zinc on the inside leaving the copper coating. Stainless steel would also be neat, as I expect the muriatic to attack it. That would show that the stainless is corrosion resistant, not corrosion proof.

Good luck, and have fun!

Lee Gearhart
metallurgist - E. Aurora, New York
2003

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I do not think you should be doing a project using acid with a 5th grader. But that's my opinion. Because I too am a 5th grader. Catherine

Catherine P [surname deleted for privacy by Editor]
- Norwood, North Carolina
2005