.
Cut some post-1982 pennies into tiny pieces to expose the zinc core and leave them in these three materials for a week and see what effect you discover. Good luck.
Ted Mooney, P.E. RET
Brick, New Jersey
November 4, 2008
My son is also doing a science fair project using different pH's to see the effect they have on the rate of oxidation of copper and iron. We are removing the metals from their test tubes for 1/2 hr daily in order for the oxidation to occur. I'm just trying to verify that our results are correct thus far. It seems our iron isn't faring too well in the lower pH's but both the copper and the iron seem to be faring the best in the highest pH. Is this correct? Just trying to make sure we haven't goofed somewhere along the way.Sharon Kleszynski
- Manteno, Illinois
November 7, 2008
Hi, Sharon. Science is different than spelling or arithmetic; the object is not for your son to get the "right" answer like in spelling or arithmetic. The object is to learn how to form a hypothesis and to develop a test procedure that tends to confirm or disprove the hypothesis. You set up a test procedure, you honestly and accurately record your observations, and then you can try to understand and explain those observations. But your observations are non negotiable! You never ever change them even if the teacher and every other student got contrary results.
It is actually better if he doesn't know the results to expect, because then he won't be tempted to discount what he has seen, or repeat things until it turns out "right" due to some random event. If he feels pressure to get the "right" answer, he will be tempted to practice "junk science".
It really is important for him to understand the critical difference between things he has observed and his possible explanations for what he sees. Get a composition book =>
If he starts writing "... because the copper metal is being converted to copper sulphate", stop him -- because he didn't observe that, he is presuming that. He should save explanations of why until after the experiment is complete.
If he learns to clearly differentiate between what he has actually observed vs. people's theories for why it happened, the project has been a huge success. If he learns to fudge his observations just a little bit so it's easier to arrive at the popular conclusions, the project was a disaster. Best of luck!
Ted Mooney, P.E. RET
Brick, New Jersey
August 2, 2009
I have recently done the same sort of thing.
I had to conduct an experiment which explored whether acids or bases had a larger effect on metals. I decided to conduct an experiment that tested corrosion.
I used un-galvanised steel, a very simple and cheap product. (I purchased small corrugated pieces in a packet from the hardware store).
The acids and bases that I used were simple household ones such as acids- vinegar, lemon juice. and bases- ammonia and shampoo.
This experiment, although simple as it is, provided excellent results that I was able to assess and discuss very successfully. It was also very cost-efficient and could be conducted in my own time because it wasn't dangerous. All of the materials were so easily accessed.
Household acids have a high corrosive affect on metals!
- Sydney, Australia
opinion! April 16, 2011
I stumbled across this page because I'm doing some research on dissolving powder coatings on metals without destroying the integrity of the substructure. The postings didn't really apply to my situation but I figured I would add my two cents to the subject. Ted, I agree with everything you have said and it is all completely true in my eyes. I graduated a couple years ago with a BS in Mechanical Engineering so I have had a decent amount of schooling. Learned a lot of great things, learned a lot of useless trivia, also forgot a lot.
I recently tried to soak a wheel in muriatic acid to dissolve the existing powder coating. Found out that I had committed a huge brain fart when I pulled the HOT wheel out of my smoking tub of acid. Completely forgot about how acids affects metal, especially strong acids like hydrochloric.