School project: Rusting nails experiment

A. Salt water is more corrosive than fresh water, so your result is hard to understand. But I don't know what you are trying to say about the Titanic -- sure, it's rusty, but it's been a hundred years!

A. Actually I did this same experiment in school with increments of 5 g of salt with 5 bottles and 100 ml of water and iron nails. The salt seems to protect the nail from rusting but I don't know why (probably because I didn't research anything) but the salt (table salt) does indeed preserve the iron nail.

A. Considering the name of your experiment, Reeshavia, and that you want to make it more complex, why not try something nobody has done on these pages yet: use an aquarium bubbler to make sure one of the trials has plenty of oxygen, and boil the water in the other, then let it cool, to try to minimize the oxygen in the other. But just use one type of water rather than confusing the issue.

A. I am doing this right now but the salt one is rusting faster

A. Hi, Amber. I'd say water. But the real issue here is carefully defining and understanding what the words you are using mean.

If one of those liquids dissolved the nails pretty rapidly but it did not cause a rusty brown color, would you call it better at rusting nails? If one of those liquids caused a lot of rustiness when you spritzed the nails with it and let it dry, but it did not cause rustiness while the nail sat in it, would you call it better at rusting nails?

It is quite hard, but very important, for you to have a complete understanding of what you mean when you claim something for your science experiment :-)

Regards,

Q. I'm a Junior Certificate student in Ireland. I'm currently investigating various science experiments as part of the science course, and I'm currently trying to find some substances that prevent corrosion of steel/iron.
As you may know, when iron and/or steel are exposed to water and oxygen, they rust. I'm looking for various substances that prevent either oxygen or water (or both) from coming into contact with the steel/iron, thus preventing corrosion, e.g. vegetable oil.
If anyone has any suggestions, please answer quickly, as my time is somewhat limited, and I would like to begin the experiments soon.
Thank you.

A. Hi, Treasa, you're doing fine. You can try paints, oils, waxes of various types, lipstick, chapstick. Include vaseline petroleum jelly and read up on the use of Cosmoline during WWII.

Regards,

Q. Thank you very much for the reply. It certainly helped and I now have a few more ideas for my project.
Another thing I'm curious about:- How long would zinc foil prevent a nail from rusting, on average? How long would corrosion of the nail be prevented, if I placed a negative charge (or positive) in the water? Would there be any effect?
Thanks again!

A. Making the nail cathodic (-) should stop corrosion indefinitely. Connecting it to zinc foil should do the same until the zinc dissolved away. Steel hulled ships use zinc anodes which dissolve away in lieu of the hull rusting away.

Regards,

Hi Piero. Olive oil is not water-based, it is oil; and like other oils, it does not corrode iron. If you have studied ionization, oils don't ionize and don't have ions in them that will attack iron.

Vinegar is an acid;

Regards,

A. Hi, Tej. Suppose you went to your school boys' room and found it to be dirty all week, and you saw one of those tags that says "Cleaned and Inspected by" and the lines had no entries for the whole week ... then you went in the next day and the card was all filled out with initials and dates for each day of the previous week? You'd say that's wrong, somebody is not being honest.

Actually you're not supposed to write anything in that old daily log now, because it was supposed to be written at the time, not later :-)

So if you have enough time, start the experiment over again and write what you see each day, even if it is "no change observed".

If you're not going to do that, a "mental reservation" is better than a lie. "No changes recorded" may imply that you observed it and there was no change and you wrote that down at the time, but it can also mean that no observation was recorded :-)

Regards,

A. Hi, Nancy. I think the first thing to do when an experiment yields surprising results is to challenge your assumptions and experimental procedure.

I would double check the label on the nails, not go by hearsay. Then I would check them with a magnet to make sure they were steel. Then I would sand them with sandpaper, and scrub them with detergent and a toothbrush while wearing gloves, and then rinse them well to make absolutely sure they were clean bare steel. Then I would repeat the immersions in the various liquids.

And I would make sure these efforts were recorded in my report, and expect an A for the careful effort and triple checking :-)

Regards,

A. Hi, Priyal. Your teacher is eager for you to do the experiment and find out. Keep a good log book and you'll be able to answer every question!

Regards,

A. Hi Charlie. See my response to Treasa, March 2, 2009. There's also electroplating with a bunch of different possible metals, galvanizing, powder coating, salt bath nitriding, painting, sacrificial anodes ...

Your librarian can direct you to an age-appropriate book on corrosion. Good luck.

Regards,

A. Hi Jubill. Be careful that you understand and explain exactly what you mean by "maintain its form and not rust" and "make the nail rust faster". And maintain a good "Lab book" as you set up the experiment and as you take readings.

Yes, it sounds like an excellent experiment. Let us know which coating protects best, and which type of water makes the nail rust faster. Good luck.

Regards,