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topic 26409

To rust and trust


2003

Q. I am in 7th grade at Ruby Sue Clifton Middle School. My science fair project is What is the relationship between pH and the corrosion of nails? My substances are water, vinegar, orange juice, and lemon juice. I am using 10 containers of each liquid substance just in case there is a problem. Water is corroding the nail the most and at the fastest pace. My project has taken place over a time period of 4 weeks. The nail in the water was the only nail rusting after 2 weeks and a half. Then, the vinegar-filled container slowly began its rusting process. The orange and lemon juice-filled containers have not had any physical/chemical change yet. The pH for the liquids are: Water-7, Orange Juice-3, Lemon Juice-2, Vinegar-4. Why isn't the Orange Juice and Lemon Juice causing the nail to rust? My hypothesis was the lower the pH, the more acidic the substance, the faster the nail corroded, and the more the nail rusted. That was the answer to my problem which I stated before. But now, I question my hypothesis. Am I right, or should I give my results the benefit of a doubt?

Marilyn F [last name deleted for privacy by Editor]
student - Houston, Texas


"Hands-on" learning is fun, maybe try a precision scale? . . .

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Electronic scale

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2003

A. This sounds like a well done project, Marilyn. I think, however, that there is an assumption in the way you are phrasing your question that is a problem and is causing you difficulty. You are assuming that the amount of corrosion and the amount of visible rust are one and the same thing (or at least you are using those terms interchangeably). That is not true, and it probably explains your results.

The problem is that it is possible for iron to corrode, and to dissolve into the liquids in question without forming visible rust. In fact, low pH liquids like hydrochloric acid (pH less that 1) are used in industry to remove rust because they dissolve rust faster than they dissolve metal -- with the result that the metal that started out rusty comes out of the acid rust-free even though the iron can dissolve into this very corrosive acid.

So I think your old hypothesis was proven wrong and your new hypothesis could be that water will cause "more and quicker visible rusting" than the other liquids (but not necessarily more corrosion). An alternate hypothesis might be that low pH liquids cause more corrosion (but not more rusting). That is a good hypothesis but may be difficult to prove or disprove unless your school has a very sensitive scale (called an analytical balance) to measure how much metal has been dissolved away. If you have the money and a strong interest, you can buy a quite accurate electronic pocket scale, measure the weight of the nail before the experiment, and after wiping any rust off after the experiment, and see if you can determine how much iron corroded away. Good luck forward.

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


2003

Q. My vinegar has started to evaporate. It is quite confusing to me. I am still deep in thought about why the orange juice and the lemon juice will not rust the nail. So, this is what I have concluded from your reply to my first message. Corrosion is the iron that has fallen off of the nail into the liquid? Rust is when the iron actually starts falling off of the nail? Is that right?

Marilyn F [returning]
student - Houston, Texas


2003

A. Close but not exactly, Marilyn. The nail is iron. When iron reacts with oxygen in the air or in water it forms an iron oxide which is visible brown rust. But the iron can also react with an acid like vinegar or lemon juice and dissolve into the liquid, like salt is dissolved in sea water; in this case the dissolved iron may not be visible and obvious. The acid will actually dissolve rust (iron oxide), effectively stopping you from seeing the corrosion as a brown corrosion product. Either way the iron is corroding, but in one case the corrosion products are very visible as brown rust and in the other case they are less visible as a dissolved salt in the liquid.

Based on your findings, again I think your hypothesis is that water will cause more visible rust on a nail than vinegar or lemon juice (but that is not the same thing as saying that plain water is more corrosive). I think you'd find the vinegar and lemon juice caused more corrosion than water, even though it's not visible as rust. This you could determine by weighing the nail before the experiment and weighing it again afterwards. Good luck.

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


2004

Q. I am in the understanding that the lower the pH, the greater the possibility of rusting to occur. Is this assumption right? My experience has proved the exact opposite. It has proved that the lower the pH, the lesser the possibility of rusting to occur. For my conclusion, should I just put that the nails started rusting in order from greatest to least pH? Or should I put the fact that orange juice and lemon juice rusted the fastest, but there were just variables preventing me from seeing the process? In general, what is the relationship between pH and the rusting of nails? Is there a relationship at all? Please respond A.S.A.P

P.S.: Does how much acid my liquids contain have something to do with the rusting of the nails? My mother asked.

P.S.S: Concerning this experiment, what could I list on a bar graph? Thank you very much and don't forget to answer all the questions.

Marilyn F [returning]
student - Houston, Texas


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"Naked Eggs and Flying Potatoes: Unforgettable Experiments that Make Science Fun"
by Steve Spangler
from Abe Books
or
info on Amazon



affil. link
"Earth Science for Every Kid: 101 Easy Experiments That Really Work"
by Janice VanCleave
from Abe Books
or
info on Amazon

2004

A. Hi again. Your assignment may be to "answer all the questions", Marilyn -- but that's not our job or our goal. My goal is to try to assist in a way that will help make your quiet contemplation be most productive :-)

Again I'll say that you have done a great job on your project so far. Tell your mom that pH and 'how much acid' are pretty much the same thing. The lower the pH, the more acid a liquid is. So, if your pH readings were correct, the lemon juice is the most acid, orange juice the second most, vinegar the third most acid, and water the least acid.

The thing to do now is to restrict your conclusions to what you actually learned, and to separate your conjectures from your conclusions. You have learned that the nails in the water rusted fastest, and the nails in the vinegar rusted second fastest. And the nails in the orange juice and lemon juice did not rust. Those are valid conclusions. It is only a conjecture, though, that if the test were run for a longer time that the nails in either the lemon juice or orange juice would rust at all, and it's only a conjecture that the nails in the orange juice will rust next and the lemon juice will rust last. It's okay to make those conjectures (guesses, hypotheses), but don't confuse them with actual experimental results!

Finally, be careful that words you have been using interchangeably as synonyms are not really synonyms. Your experiment measured, by eye, the appearance of visible brown rust; it did not measure the amount of corrosion. And the fact that you saw no rust in two liquids does not mean that there has been "no physical/chemical change" in the nails, it only means there was no visible brown rust. It is possible that some physical/chemical change occurred that you have not monitored; that is not faulting your excellent work, it's just saying that a 7th grader observing rust by eye cannot really make quite so strong a statement as that.

Your bar graph could show pH of the four liquids versus days until rusting occurred. The "days until rusting" for two of the bars would read "no rust observed in xx days".

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


2004

A. You are right in saying the lower the pH the more acid is present, and this explains your observations. "Rust", as you are considering it, is a complex mixture of insoluble iron oxides and hydroxides - it is usually brown or grey/black/brown in colour.

However, because you don't see this in an acidic solution doesn't mean the nail hasn't been attacked. Since there is so much acid present, the acid will react with the iron and rust to form a soluble salt, so you won't see it as a solid lump of crud. One thing you may want to do is to repeat the experiment but weigh the nails very accurately before you start and at certain times during the experiment. Make sure the nails are dry before you reweigh them!. You will see a weight loss with time, and this is corrosion, although it is not necessarily "rusting". Rusting is only one form of corrosion.

Your comments about orange and lemon juice are interesting - are they real fruit juices or stuff you got out of a cheap supermarket bottle? If they are the real things, these contain both citric acid and ascorbic acid (vitamin C). Citric acid is a mildly strong acid and can be used under some conditions to protect metals, especially stainless steels. However, ascorbic acid is a much weaker acid and is a mild reducing agent, so it too may offer some protection to the nail. For good rusting corrosion you need lots of air or preferably oxygen, so perhaps you have prevented the air getting to the nail. I like the effort you have put into the work and the degree of interest it has generated in you. I hope you get the rewards you deserve for all your effort.

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK


2004

thumbs up signThank you so very much for your help! God bless and I hope you continue to spread your knowledge to other students.

Marilyn F [returning]
student - Houston, Texas



2005

Q. Will a nail disintegrate in Coke Cola over a long period of time? My name is Collin and I am doing my 6th grade science project.
I would like to find out how long or if a galvanized nail would disintegrate in coca cola.

Collin R [last name deleted for privacy by Editor]
- Rochester, Illinois


2005

thumbs up signI would like for you to find out, too, Collin. Do you have the galvanized nail immersed in the coca cola yet? :-)

The first lesson to be learned from a science project, no matter what grade you are in, is that you must never try to bend the experiment to get the results you are "supposed" to get. Instead you must record your actual results first and then attempt to explain those actual results.

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



2006

Q. Hi I am doing an experiment on Coke dissolving a nail, it is for my Science Fair and I am in 8th grade and go to Middle School and I have lately been wondering if the facts that I got off of a chain letter are actually true, but I have done some searching and I don't think that it is true, I might even fail this, because I think it won't work. If somebody could help me out that would be great!

Tawney H [last name deleted for privacy by Editor]
- Walled Lake, Michigan


2006

Ack! Unfortunately you may fail if you are not more careful to express yourself more clearly than you have done so far, Tawney :-)
You have not told us what the chain letter said, nor what was said in the contradictory evidence you came up with. No one but a mind reader could possibly help you know whether the facts claimed in the chain letter are true based on what you have told us so far :-)

Please tell us what the chain letter said, and what your other research said. Most importantly, tell us what happened when you tried to dissolve a nail with Coke. Thanks.

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



2006

Q. I was wondering what will rust a nail: vinegar, lemon juice, and soda. My hypothesis is that the nails with vinegar will rust the most help me guys!

Eric H [last name deleted for privacy by Editor]
student - Orlando, Florida


2006

A. You have formulated your hypothesis, Eric, and now you must conduct an experiment to support it or refute it.

Never ask what answer you are supposed to get from the experiment before you do the experiment! That is called "junk science"! Junk science means deciding what you would like the answer to be, or what result would make you feel good, and then you keep redoing the experiment, dismissing the results you don't like, and phonying up the experiment and making it wackier until you finally get a result you wanted in the first place. It's a curse and I would hope your science teacher would never let his/her students get away with it.

Put your nails in vinegar, lemon juice, and soda and carefully record your results. After the results have been RECORDED IN WRITING you then can go back and try to explain them. Get back to us after you have recorded at least some results in writing. Good luck.

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



2006

Q. I am in year 8 and I am doing a science project of rusting and corrosion. The question that I was asked to answer was "Does salt water have any effect on the rusting of iron?". I have searched many places for this information but none have been successful. I have to do a report on this. All I need is conclusion. Thank you.

Kryska H [last name deleted for privacy by Editor]
student - Sydney, NSW, Australia


2006

Well, Kryska, give us your hypothesis and your experimental observations and we'll be happy to help you with your conclusion. A conclusion without these is as silly as trying to top off a Christmas tree with a star or an angel before you have the tree :-)

Neither christmas tree toppers nor conclusions can just hang up in the air with nothing supporting them.

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



2006

Q. I am doing a project on which solution best helps prevent rusting and I am wondering if I need to weigh the nails before and after rusting, due to what I have learned from a previous question. You say that when the acid effects the metal it is not as obvious as in water. Why is this so and will lemon juice and vinegar make nails rust?

thanks for your help

Abbey [last name deleted for privacy by Editor]
student - Georgia


2006

Hi, Abbey. Acid dissolves metal but it also dissolves rust -- in fact, rust dissolves faster and easier in acid than the raw metal does. So acid is often used to remove rust from metal. Is that clearer? If you weigh the nails before and after immersion in acid you will find that they are lighter after immersion because the acid dissolved some of the metal.

If you dip a nail in vinegar or lemon juice for a few minutes it will remove rust. If you leave a nail in it for weeks it will probably eventually come out rusted because iron will keep dissolving until the solution is completely saturated with iron, and the iron cannot stay dissolved anymore as the acid and water evaporate.

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



2007

Q. Hey there I'm doing a science fair project; it is about what will dissolve a metal nail quicker Clorox, Coca-Cola, distilled water or city water. My teacher is asking us to write a research paper to go along with it an I have to have five sources. I'm not sure of a person to ask about it I have everything else but I need a person to give me some type of input.So do you think you could help me. thanks

Logan B [last name deleted for privacy by Editor]
- Georgia


2007

Please tell us your hypothesis, your experimental procedure, your results, and your conclusion, Logan. Then someone can comment on it. To tell you what the result should be before you do the experiment would be to encourage you to practice 'junk science', and that would likely get you an 'F'. Has your teacher told you the point of this experiment? Have you been told or found out what bleach is and what coca-cola is? Good luck.

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



2007

Q. I'm doing an experiment at home for school on which nail rust faster in either water or vinegar and my nail in vinegar never rusted. I was wondering why...

Mary [last name deleted for privacy by Editor]
- Sydney, Australia


2007

We've already given the reason for that several times just on this one page alone, Mary. I'll be more than happy to try again if you are having difficulty understanding it, but your question may be reflecting the attitude "just give me the answer" :-)

So, try express your question in terms of what we've already said about it, and then I will be happy to try to reword it. Thanks.

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



2007

Q. I am doing a science fair project on rust. I am in 7th grade. My question is- "Do certain liquids cause metal to rust faster?" I already know the answer to that question by browsing different forums, but I was wondering if I should use steel wool or nails to conduct my experiment. I will be using lemon juice, water, and salt water, and I will put these liquids into little jars. Would either nails or steel wool be more accurate to measure the rust? Do you know an exact way to measure rust, or should I just observe and record the results? If you could help me I would appreciate it.

Victoria S [last name deleted for privacy by Editor]
- Taunton, Massachusetts


2007

Steel wool has far greater surface area than a nail, Victoria, so it will react much faster and is probably better if you are going to judge visible rust. I would use just a little steel wool in each jar because you don't want so much that the liquid becomes saturated or "exhausted". I'd probably weigh equal amounts of steel wool to put in each jar. The steel wool will both gain weight as rust starts agglomerating on it, and lose weight as the steel dissolves and as rust flakes off. So I think you'd have a hard time making a quantitative measurement. But if one of the three pieces rusts really badly you could pour the remains through a colander or tea strainer and say that it dissolved so much that it passed through. I think if you started with soap-free 0000 steel wool [affil. link to Rockler] from the furniture refinishing section of a store rather than Brillo pads, it should rust really quickly (a few days). Good luck.

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


January 16, 2008

I asked a few weeks ago if steel wool would rust better than nails for a science project I had, and it worked! Thank you Ted :).

I did my project on what liquid rusts metal faster- salt water, water, or lemon juice. The salt water worked the best- but I have a question. I know salt water is a better electrical conductor than water, but is that why it rusts better? Or is it because the salt is like an acid?

Victoria S [returning]
- Taunton, Massachusetts


January 17, 2008

Rusting is an electrochemical process, Victoria, so the process can proceed faster when the liquid is a better electrical conductor, and saltwater is a better electrical conductor that plain water because the salt ions dissolved in it can carry electrical charges from one place to another. Acids cause corrosion or dissolving of the steel, but they generally don't cause rusting (while still immersed) because acids dissolves rust faster than they dissolve the metal.

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



2007

Q. I'm in 6th grade and I'm doing a project on if nails will rust faster in coke, water or sprite. I found out in a 10-day time period that water will rust, coke will get thick and gooey, and sprite will turn more yellow. The problem is that I just found out I need to do research on the topic......and I can't find any research on if nails will rust faster in coke water or sprite in a 6th grade level.....one I can actually understand. I don't have much time to start another project, so please help me find a website about it or tell me about it

MADELYN

Madelyn H [last name deleted for privacy by Editor]
student - Orange Park, Florida


2007

It is good that you made the observation that Coke turns gooey and Sprite gets yellow, and wrote it down, Madelyn. But those observations do not address the question. You were asked which of the three cause nails to rust, and apparently your answer is: only water.

You will not find research on exactly your question. No real research is done on it because it's just not important: people don't dissolve nails into Coke or Sprite in real life (outside of grammar school science projects). But you will find that acid dissolves rust (because that's important in real life) and that soft drinks contain a mild acid. Then you have to put two and two together. But I think you'll make faster and much better progress with your librarian's help than on the web. Good luck.

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



2007

Q. Will sprite dissolve a metal nail? if so will it dissolve it faster than coke? I am in 8th grade and have to do a science fair project and was wondering, does anyone know if sprite will dissolve a metal nail? if so how long does it take.

Kari J [last name deleted for privacy by Editor]
8th grade student - midland, Michigan


2007

A. Even if someone knows about it, if you're doing a science project you should try it yourself, I have recently done a science project and posted it- it's above yours, anyway don't ask about it ... you should try it and see how long it takes. If you don't have enough time to finish your project take what you have and use that, but keep the project going.

P.S. if you really want to know look it up more (likely in library I found lots of information there).

Madelyn H, again
- orange park, Florida


2007

Thanks, Madelyn. Your advice to turn in what you have but keep the experiment going sounds very good, and I agree that a library is a great source for the research.

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


January 2, 2008

Q. Hi I'm in 8th grade and I'm doing a science fair project on how the pH level of pop affects the corrosion of nails. I tested with Coke, Sprite, Mountain Dew, and Fanta. Alongside it, I also tested water. I used Steel, non-galvanized finishing nails. How come the nails didn't rust? By the way, I left the nails in the liquids for a month. I have 3 days until the due date for the science fair and I'm really confused! I know you've printed a ton of rusting nails boards and I've read all of them but this is still confusing me. Please help! Thanks in advance!

Julie V [last name deleted for privacy by Editor]
student - Malibu, California


January 18, 2008

I am amazed that they didn't rust in a month. Are you sure they are not stainless steel nails? Assuming they are not stainless steel, use very clean Sandpaper [affil. link to product info at Rockler] on them while wearing gloves to avoid finger oils to give them a clean, raw finish and they will rust within a day or so.

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



May 21, 2008

Q. I am 10 and in the 5th grade. My experiment is what will corrode? I put aluminum foil, a copper penny, steel wool and a stainless steel spoon into a bowl of water and a bowl of orange juice and left it there for 7 days. My hypothesis is that the steel wool and stainless steel spoon will corrode in the water, and nothing will corrode in the orange juice. I just got my results today. I am confused-nothing formed in the orange juice--so that worked. I think that is because of the acid in the juice.

But in the water the foil and spoon look like they have rust on it--but when I wiped it off there wasn't any on it? The steel wool was rusty. The penny was clean. I am not sure how to explain this. I thought the steel wool would rust cause nothing was protecting it--I thought the stainless steel spoon would because it has steel in it? I am not sure what I am learning from this?

Trent W [last name deleted for privacy by Editor]
student - LaPorte, Indiana


May 21, 2008

Hi, Trent. When doing science there's nothing wrong with using what you already know when forming your hypothesis. You eat with stainless steel flatware every day. Your parents don't buy new flatware every few days, do they? Do you really think it rapidly rusts when exposed to water? So don't be surprised that your hypothesis that it will rapidly rust was proven wrong. The rust probably came from the steel wool, so it rubbed right off the foil and the spoon.

Regards,

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



affil. link
VOM meter

January 2, 2009

Q. Hi, I am an eight grader and for my science fair project I am conducting an experiment, how does the pH level of water affect the rate of rusting. My hypothesis is the lower the pH the faster the rusting. I have water of different pHs from a machine that is called "jupiter ionizer". It takes tap water and changes it to water with a different pH. The range is from pH 3 to the pH 10. I am using some carpet tacks and submerging them in the water. I recently heard from my mother that the pH of the water probably changed to normal pH 7 water since it was let to sit for a few days. I was wondering if this is true and if so should I use vinegar, and lemon juice as the acidic liquids. Do you know any household items that can be used as alkaline liquids for my experiment. I want to try and get as many pH liquids a possible.
I also have a problem with measuring the rust. Is it possible to measure rust by conductivity. Since iron is a good conductor of electricity but rust isn't (I found it at a website) If you can measure rust by conductivity how do you do it. My teacher said I can use a volt meter but I am still unsure how to use a voltmeter to measure the conductivity of the iron nail. Also, where can you get a scale that can measure nails and rust accurately.
thank you for your time.

Michelle C [last name deleted for privacy by Editor]
- Houston, Texas


affil. link
Electronic scale

January 10, 2009

Hi, Michelle. It would be best if your school has an analytical balance. This is a very precision scale that even has a glass door on it to keep light breezes from affecting the weight. But if you have the money and enjoy the subject, you can get a very accurate pocket scale on line for about $15. See the Amazon ad at right =>

I think you misunderstood your teacher; you can't measure rusting in a useful way with a voltmeter.

Cover your experiment dish with Saran wrap to keep the acid from evaporating from the vinegar. Common alkalis include bleach (don't mix with other stuff except water), laundry detergent, and antacids like Milk of Magnesia or Mylanta. You probably could mash up a Tums or Rolaids if you don't have a liquid antacid.

Regards,

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


March 9, 2009

Q. Hi I'm Kenny from Singapore and I'm in Secondary One. I'm not sure what is the counterpart for Sec. 1 in the US, so I apologize.

For our science project, we have decided to test on how the acidity of a liquid affects the rusting of iron nails (our hypothesis). In each set-up, we put 3 iron nails into each container. Each container contains different liquids (detergent, apple juice, orange juice and tap water). We leave them in the Science Lab in school, observe the nails every other day and weigh them every 5 days. The experiment ends after 15 days. We are currently in the process of repeating the experiment to make sure that there are no irregularities in our results.
However, from my understanding after reading this thread, weighing the iron nails is not a foolproof way to measure the amount of rust. I have observed that from our experiment as the all the nails actually lose weight , rather than gain weight. Certain liquids also cause more corrosion than others. Some even "clean" the rust.

What do you suggest we do? We are supposed to write a scientific report on our experiment. Should we change the hypothesis altogether? Or should we find a better way to measure the rusting?

Kenny L [last name deleted for privacy by Editor]
- Singapore


March 12, 2009

Hi, Kenny. Just use the word corrosion instead of rust, and you're back on track. Yes, the nails will lose weight because you'll rub off any rust before weighing them and will be weighing only what's left of the metal.

Regards,

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


April 4, 2009

Q. My 4th grader wants to corrode metal

His hypothesis is if he puts similar metals in rubbing alcohol, lemon juice and vinegar it will corrode faster than in tap water.

He wants to use a chuckee cheese coin (I don't think this is metal), key ring, thumb tack and a screw

I read through the previous posts and I had some other questions.

Should he use distilled vinegar or apple cider vinegar?
(I've read that distilled vinegar is better for cleaning and apple cider vinegar is better for cooking.)
What kind of containers should he use to put the liquids in?
Is plastic suitable or does he need to use glass?
Is there an inexpensive way to measure the corrosion of the items he wants to use?
Will a scale that measures ounces work?
Does he need real lemons or will bottled lemon juice work just as good?

Lydia Taylor
student's mother - Orlando, Florida


April 10, 2009

A. Hello, Lydia. If he's allowed to pick the liquids he wants to use, it makes no difference whether he picks distilled vs. apple vinegar, or real lemons vs. bottled lemon juice. If you're asking whether one of these is more corrosive than the other, though, isn't that the kind of thing these experiments are supposed to determine?

Glass is best, but plastics that are used for cups and bowls and food containers are unlikely to be affected by these liquids. A postal scale will not have anywhere near the precision necessary to gauge corrosion; but an electronic pocket scale might. Good luck.

Regards,

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


July 15, 2009

Q. Hey I'm currently a senior student and doing my final chem experiment. I am a little confused with my topic. My experiment is investigating how when salt is dissolved in water it will increase the rate at which corrosion of steel wool occurs. I understand that the salt will quicken the process because the salt is a better conductor than water and will attract the ions to the water molecule. However although I understand this, I am struggling to develop a way to collect data and describe what I expect to happen. Firstly because corrosion "eats away" at a metal I am led to believe that the mass of the steel wool will be reduced. Secondly will the mass of the entire experiment remain the same throughout? and finally at the end of the duration of the experiment I think rust particles will have formed in the beaker. Therefore to collect numerical data, I will collect the rust on filter paper, and wash the steel wool to ensure all rust particles have broken away. I will weigh the rust the weigh the new mass of steel wool. I assume that if the mass of the rust is added to that of the steel wool is will equal that of the original mass of steel wool.
your help would be greatly appreciated Letty

Letty Lou
student - QLD, Australia


July 16, 2009

Hi, Letty.

What do you mean by 'attract the ions to the water molecule'?

If your experiment assumes Fe + O2 --> FeO2, would you expect the Fe to weigh the same as the FeO2? I certainly wouldn't.

I would put the steel wool in the beaker, warm it to drive out moisture and weigh it. At the end of the experiment I would let all the water dry out, warm it, and weigh the remains in the beaker. The only thing is, the salt in the saltwater will not evaporate, so you must separately weigh the salt in the water before you begin.

Regards,

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



November 15, 2009

Q. Hello,
My name is Ben. I am doing my Science project for my 6th grade science requirement. My problem statement is "Which makes nails rust fastest, Coke, Gatorade, or Water?" My hypothesis is that Coke will cause rust the quickest. I am not sure how to measure the amount of rust and how to put my observations in a graph. What is the best way to measure the amount of rust on the nails?
Thank you,
Ben

Ben B
student - McDonough, Georgia


November 16, 2009

Hi, Ben. I suspect that you don't have a clear picture in your mind of exactly what you mean by rust. Assuming the school doesn't have an analytical balance, appearance is all you have to go by, and it will be a bit subjective.

I would leave the nails in the liquids until one of them shows a little rust, then pull it out and write down how many days it had been. Pull out the next one when it shows a little rust, and write down how many days. Continue until all (or all but one) have rusted. Then graph the name of the liquid vs. the number of days until first rust.

Regards,

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



August 31, 2010

Q. Hey my name is Jennifer and I'm in 8th Grade and I'm doing my science fair project on what rusts faster a penny, a paper clip, or a needle in either colored pop, orange juice, or in the monster energy drink. My problem is that I don't know how to set it up and I know nothing about rust or how to keep record of it.

Jennier J
- Carpentersville, Illinois, United States


August 31, 2010

A. Hi, Jennifer

Start with a "lab book". This is a composition book, rather than loose pages. The first thing you do is number the pages because this will remind you that you never rip a page out and you never erase. If at any point you write something that doesn't belong, strike it through but leave it legible. Now you write the date and time in it and you start writing . . .

You have three objects to test and three solutions to test. Three times three is nine, so you'll need 9 testing cups. You write that plan down and date it.

Have your parents help you find or buy 9 testing cups; maybe the disposable thin plastic bathroom cups would be good. Partially fill three cups each with the three liquids, and put a penny in one cup of each different liquid, and the same with the paper clip and needle.

Now every day for a week or two you simply look at the nine cups, see what you see, and write down the date and time and what you see in whatever words work for you.

As you start seeing things happen, some ideas and theories will start bubbling up; let them take you where they take you and start doing some research to try to puzzle out what you are seeing. Good luck.

Regards,

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



January 15, 2011

Q. Hi, could you help my daughter, Emma, who is in third grade and doing a science fair project on liquids rusting nails. We found that the nail with the vinegar actually formed a very small amount of rust right at the vinegar line after about 3 minutes. After an hour, though, you couldn't see the rust ( I guess it dissolved), and there is now thick black gunk on the top of the nail not in the vinegar. What is the black stuff?

Rebecca Cavendish
- Jupiter, Florida, United States

----
Ed. note: It's rust, Rebecca. See answer to Mandy H., Feb. 15, 2014 please.


August 8, 2011

Q. Hi. we have a research paper about the removing of rust from nails using a pili pulp oil. Our question is do we use analytical balance to measure the weight of the rust?

Kris B
student - Philippines


August 2011

A. Yes, Kris.

You weigh the rusty nail, then treat it, then remove the pili pulp oil with an appropriate solvent, and weigh it again to see how much (if any) rust was removed. But I'm not sure how you would decide that removing the rust was a good and beneficial thing by weighing it :-)

It would seem to me that the rust is either a functional problem or an appearance problem, and the question I would have is whether the pili pulp oil improved the function or appearance.

Regards,

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


August 17, 2011

Q. I am also doing an experiment on the rate of corrosion on steel wool. I used black coffee, vinegar, lemon and orange juice and soda as my acids. I found that vinegar corroded the steel wool more than any other acid. This was followed by orange juice, lemon juice, soda and finally soda. The part I am stuck on is the data processing section. Is it alright if I give the chemical equation of each acid with iron and show the oxidized elements or are there more calculations to do? I would really appreciate an answer as I am stuck on this part of my experiment.

P.S- Which acid is found in black coffee?

John F.
- San Diego, California


October 8, 2011

A. Black coffee has a pH of 5

Nick R.
- Sydney NSW Australia



October 12, 2011

Q. I'm in sixth grade ,and I am doing a project on rusting. Do different liquids effect the rusting of iron?
I need help on finding the pH levels of salt water, bleach, vinegar, and oil.
Thank you so much!
and if you have any other info on this to help me please feel free to tell me it.
p.s. from all the 68 websites I have researched on this is THE BEST ! It has helped soooooo much.

Rinah D
School - Irvine, California, United States


affil. link
pH Paper

October 13, 2011

A. Hi, Rinah. Thanks for the kind words.

Yes, how fast the iron corrodes and how much it rusts will depend upon the liquid that you expose it to. Your science teacher should have pH paper available for you. You dip it into the liquid and it turns different color depending on the pH.

It's cheap, fast, easy, safe ... and makes much more sense than trying to research the answers on the internet and trusting dubious sources :-)

Regards,

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


October 18, 2011

Q. Hi, does iron rust more with high pH levels or low? This is for my research. My question is in which liquid iron rusts the most?

Rinah D [returning]
- Irvine, California, USA


October 18, 2011

A. Hi, Rinah.

Has the teacher given you pH paper and shown you how to use it? What pHs have you tried? Are your questions 100 percent clear in your mind?

What liquids have you tried, and what were the results. I think we can help you reconcile your results with theory if you tell us your results; but to simply tell you the answers would be to defeat the purpose of the assignment.

Regards,

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



May 10, 2012

Q. I am 7 years old. I am doing an experiment on "How will a nail rust in different liquids?". So far everything is going fine. I have a control nail in air, sea water, tap water, lemon juice and Sprite Zero. The Sprite Zero has turned black after 6 days. I have looked everywhere and have not found answer to why that has happened. Can you help me?

Jackson B [last name deleted for privacy by Editor]
- Beverly, Massachusetts USA


May 11, 2012

A. Hi. Sprite Zero is a secret formula. Without knowing what is in the secret formula, nobody can tell you for sure. But do you really mean "black" as opposed to rusty? Are the nails steel? Are they rusting in the other liquids as they should?

Regards,

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


February 1, 2013

Q. I did a science experiment to compare the corrosion of steel wool (fine grade) soaked in distilled water, lemon juice and pineapple juice. I measured the temperature change of the steel wool at one minute intervals. I found that the steel wool soaked in lemon juice had the highest temperature change followed by pineapple juice and distilled water. My question is why did brown rust only show up on the steel wool from the distilled water? The steel wool from the lemon juice turned black and got hard but rust was hard to see and I thought it would be rusty looking. The steel wool from the pineapple juice did not show any brown rust either, it was darker than the steel wool from the distilled water but not as dark as the steel wool from the lemon juice. Any help would be appreciated.

Taylor [last name deleted for privacy by Editor]
- Seneca, Illinois USA


February 2, 2013

A. Hi Taylor. Please very slowly read the first question and answer on this page and do your best to try to understand it. Acids like lemon juice will attack and dissolve the steel wool more and faster than less aggressive liquids, but they attack and dissolve rust even faster than metal.

Your temperature measurements indicated that the lemon juice was attacking the steel wool the fastest, and it probably was. But the acid is keeping the rust dissolved. If the rest of your experiment is over, you could try evaporating the liquids in oven set at about 225 °F. As you do, the rust won't be able to remain dissolved, so you should see a rapid buildup of it although the solids from the pineapple juice might disguise it somewhat.

Regards,

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


February 25, 2013

Q. Hello, I am doing my science project on which solutions will affect nails to rust fastest (water, salt water, canola oil, and lemon juice). All the rust on the nails in water, salt water, and canola oil was reddish-brown, but the nails in lemon juice had an odd black substance on them. I was just wondering what exactly the substance could be (is it rust?), and how it may have formed.

Thanks for your help anyway!

Sara E [last name deleted for privacy by Editor]
- San Jose, California, USA


February 26, 2013

A. Hi Sara. Simply guessing wouldn't make for a very scientific science project, so see if you can go beyond that.

Iron and steel contain carbon that will not dissolve in acid, so if you've dissolved some steel, it might possibly be carbon left behind. See if it wipes off on a white cloth; if it leaves a black smut somewhat similar to carbon black, and if you can prove that the lemon juice is an acid, and if you can find a reference that says that acid can produce smut on steel, you will have moved from wild guess to reasonable probability (but not proof) that it is carbon. Good luck.

Regards,

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



February 15, 2014

A. I am helping my kids with a science experiment on which liquid will rust a nail faster. We have done our experiment and the nail that was in the vinegar has a black corrosion above the water line.

26409

I can't find a single thing to tell me why that is happening. Thanks for any light you may shed on this matter.

Mandy Hartsoe
- Simpsonville, South Carolina, USA


February 2014

A. Hi Mandy. Curiosity is a strong driver of scientific progress, but let's remember that this lesson is not for me or you -- it's for the kids. So my question back to you is whether this is the first and most important thing that the kids (rather than you or I) noticed and were curious about?

This is pretty advanced for me, let alone your kids, but I believe the black gunk is "black rust". I understand that it's what forms when iron/steel rusts but there is limited oxygen available, so instead of becoming red rust Fe2O3 (which requires 3 atoms of oxygen for each 2 atoms of iron), you get black rust Fe3O4 (which requires only 4 atoms of oxygen for each 3 atoms of iron).

Vinegar fumes are coming off of the liquid, and corroding the iron above the solution level, and because this action is inside a test tube rather than out in the open, not enough oxygen can get to the nail to form that much red rust, so you get black rust.

Regards,

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


March 18, 2015

Q. Hi,
I am in grade five and doing my science on rust and nails and which liquid will make a nail rust the fastest. My liquids are water, orange juice Apple juice and coke.
My hypothesis was that coke would make the nail rust the fastest, however that is not the case. Water has made the nail rust the fastest, orange and apple juice there is no visible rust the nails look brand new and the coke has left the nail almost the same color as the coke. I was wondering why the coke would change the nails colour and why the o.j and a.j has not had any visible signs of rusting and the nail in water is covered in rust? Please help
Thank you

Ethan s [last name deleted for privacy by Editor]
- St. John's, nl, Canada


March 2015

A. Hi Ethan. This is a long page, and probably hard for fifth grade, but your exact questions are already answered on this page, some of them 3 or 4 times already. So the page should be a good exercise in reading for science, with slow and thoughtful contemplation :-)

Regards,

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Ted Mooney, P.E. RET
finishing.com - Pine Beach, New Jersey
Aloha -- an idea worth spreading



Steel wool heats up more in vinegar than in lemon juice

January 16, 2016

Q. I am a 5th grader and did an experiment on corrosion. I used 4 different liquids, distilled water, tomato juice, lemon juice and vinegar. I soaked a 1" piece of steel wool in each liquid for 30 seconds then placed each in a test tube with a thermometer and recorded the temperature over a 15 minute period. I tested each liquid three times. The lemon juice is the most acidic, but the vinegar actually had the greatest temperature change during the 15 minute period. I am wondering if there is a reason why the vinegar had the greater thermo reaction then the lemon juice even though it is less acidic. Is there something in the lemon juice that makes the reaction not as strong? Thanks!

Lucas B [last name deleted for privacy by Editor]
Student - LA, California, United States


January 2016

A. Hi Lucas. People smarter than you or I tell us that the more we learn, the more we realize how little we know. This can be a terrible frustration in science class, or it can be an inspiration because you'll forever have the fun of learning new stuff no matter how long you've been at it :-)

You've probably figured out that I'm about to deliver some bad news about what you've learned. Yep, just when you think you've learned that "pH = how acid or alkaline something is", I'm going to pull the rug out from under you and say "well, not really". There is a concept called alkalinity which might be accounting for you seeing more heat with vinegar even though you believe the pH of lemon juice is lower. There is probably "more acid" in the vinegar than in the lemon juice even though it's not reflected in the pH measurement. This video is a start towards understanding it, and you can go on from there into further researching "alkalinity" if you are interested.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com - Pine Beach, New Jersey
Aloha -- an idea worth spreading


January 18, 2016

A. Lucas,
"Most acidic" can mean a lot of things. Keep in mind that you are dealing with two different acids here. (Bonus points if you know what they are called.)

Acids are molecule that let go of H+ ions when they are in water. pH is a number that tells us how many H+ ions are floating around in that water. However, there are a lot of other factors here. Some acids let go of all the H+ they have. Chemists call these strong acids. Other acids let go of some H+ but keep some of it too. We call these weak acids. (Both of yours are weak acids.) There are a lot of different weak acids and they don't all hang onto their H+ in the same amount. If you have two beakers of different weak acids with the same pH value, it means the H+ they let go of is the same, but the amount of acid needed to get that result is different. Chemists have to be very clear when they say a number about an acid solution as to what that number represents.

Then you throw in the wrinkle of reacting with a metal, and again, it depends on what type of acid you have. Solutions of different acids with the same overall amount of acid, or the same pH, can have drastically different effects on a piece of metal.

Keep in mind that at your level of schooling, you are not expected to know everything about chemistry. The point of this is to teach scientific method. You put together an experiment, you probably said what you expect to happen, and then you did it. Now you get to say if the real data matched your expectation or not. Scientists learn a lot when the real data is something other than what they expected. Typically your report would end by suggesting another experiment to help learn more about why your expectation was wrong. For instance, you might remove the variable of different acids by only using two types of vinegar with different acid strengths. You don't have to actually DO that experiment, just say that's what you WOULD do as the logical next step.

ray kremer
Ray Kremer
Stellar Solutions, Inc.
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McHenry, Illinois
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