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How do you measure the formation of rust?

I'm doing a middle school science fair project. I have six pieces of metal and have placed them around the yard. After doing this I realized I have no way to measure the rust. I cannot use my eye. Please let me know as soon as possible if you have an answer. This is greatly appreciated!

Thanks a bunch,

Faith R.
- Dallas, Texas, United States
2004

Well...let's see. How about scraping off the rust and weighing it? Easy if you can borrow a sensitive scale or a pan balance. Somewhat more difficult if you have to make a balance, but probably worth more points. Good Luck!...and please let us know how it turns out.

Tom Gallant
- Long Beach, California, USA
2004

How do you take rust out though?

Rinah D [last name deleted for privacy by Editor]
- Irvine, California, United States
October 6, 2011

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Hi, Rinah.

The way it is done in an actual professional laboratory is the metal piece is weighed before the test starts. After the rusting period the piece is put into a chemical that washes away any rust without hurting the base metal. Then the piece is weighed again and however much weight it has lost is how much metal corroded away to rust. Professional labs may use an "analytical balance", a super precise scale accurate to 0.0001 grams and enclosed in a glass box to isolate it from even mild breezes in the laboratory.

Tom was suggesting that the rust be scraped away with a metal putty knife or the like, and be captured for weighing. It is not as exact as the laboratory method, but it may be within the capability of middle school students and would not involve chemicals that the school probably would not let you use anyway. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 6, 2011