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Rust in saltwater vs. fresh

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Q. Hi. I am in eighth grade. Last year we learned chemistry, but it was very simple, so I didn't learn anything about rust. This year, I am doing a science fair project on rust. I got some research on it, and all the metals. My project question is "Does the growth rate of rust on different metals change in saltwater and tap water. My control will just be the metal without any water. I am putting each metal in a jar full of water. I am using six metals, aluminum, zinc, steel, stainless steel, copper, and brass. How does saltwater effect rust on these different metals?

Samuel F.deleted
student - Jenkintown, Pennsylvania


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A. You may get faster results if you stir the water a few times a day to mix air (Oxygen) in with the water. How about you telling us the different effects saltwater and tap water have? After all, YOU are doing the experiment and the best answers come from what actually happens, not from what someone thinks SHOULD happen.:-)

Tom Gallant
- Long Beach, California


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Q. My daughter is doing this project this year, any recommendations or what was the outcome?

Michelle Sdeleted
- Mobile, Alabama


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A. C'mon, Michelle: knowing the expected results will corrupt the experiment :-)

That's why pharmaceutical trials must be run "double blind". If you know the "right" result it is very difficult to not overemphasize the supporting evidence and talk yourself out of recording the contradictory evidence. Have your daughter conduct the experiment exactly as the experimental procedure describes, and carefully report her results. She should get an A if she follows the instructions, accurately reports what she got, and writes it up well.

If she gets different results than the teacher wanted, what must be done is the teacher must modify the experimental procedure instructions for next time. The teacher certainly does not expect the students to falsify results to make a poor experimental procedure look good. :-)

Good luck!

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey

(for Kindle)
Unforgettable Experiments
that make Science Fun


Kids Guide to Research


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Q. Hi I'm a sixth grader and I'm going to a state science fair competition. I have a question about my project. My steel wool [linked by editor to product info at Rockler] rusted more in tap water than in salt water. The book where I got the project from says that the salt water should rust more though. How can this be?

Victoria S.deleted
Science Fair Participant - Quitman, Louisiana


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A. Books can be wrong, Victoria. Properly derived experimental results, demonstrated repeatedly, are not wrong -- they are science! I have not tried steel wool myself, but I have tried nails and seen no difference in corrosion between salt water and tap water myself. Salt water is far more conductive, so when you have dissimilar metals in contact in solution, the results may be different, but I find it very believable that the salt water does not rust the steel wool faster than tap water and have seen no evidence to lead me to believe that it does.

I'd love to see the book publisher's test notes because I'll bet the publisher collected his millions of dollars to publish this stuff without even once taking 30 minutes to test what they've written. And when it's a science book they are publishing, which is about the "Scientific Method", that's little short of criminal :-)

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


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Q. Hi, I am in the 7th grade and am doing a project about "Do steel nails rust faster in salt water than in fresh water". Everything I look up says fresh water should cause rust faster and salt water should cause rust faster. Which one should I believe? I did my experiment and they started to rust at the same time (steel nails). Help.

Chris Wdeleted
student - Waldorf, Maryland


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A. You should believe your test results, Chris. And then you should run your test again to confirm them. And then do it again to be triple sure. And then the more static you get, the more you will learn and the longer you will remember it. Because when you're sure, you're sure. And there's no feeling like it, and suddenly science is fun :-)

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Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey

Award Winning Science Fair Projects


February 7, 2008

Q. Hello, my name is Emily L. and I am doing a science fair project on if salt water can corrode metal. I am wondering if it will work and how long it will take for the salt water to start eating at the metal.? Another question that I have yet to understand is how salt water can corrode metal. It has been tested before but due to the lack of objects and time, I am wondering if a humidifier in a plastic container with the metal plates will do the trick? Thank You for your time and support.

Emily L.deleted
Student - Woodrow, Colorado


August 30, 2008

Q. How does saltwater effect different types of medals? I am doing a Science Fair Project... I am using a penny, a nickel, stainless steel, a iron nail, and a fishing hook. What should I do?

Sierra S.deleted
student - Orange County, California


October 5, 2008

Q. I am doing a science fair project on which metal will rust faster in water, iron, steel, or copper? I am doing my research right now and I'm trying to look up the reason why metal rusts faster in water than in just plain air. I couldn't find any sites that could help me, so maybe you could be the one?

Jessica B.deleted
student - Ottoville, Minnesota


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February 22, 2009

Q. Hi! I am in the 5th grade. I am doing a science fair project on what liquid makes nails rust fastest. The saltwater rusted fastest. Why is that so? I need to know ASAP!

Thanks for your time..!

Kasey Bdeleted
school - Minnesota


February 23, 2009

A. Hi, Kasey. Not everybody gets the same result, but I suppose you could claim that the salt water is more conductive so it helps electrochemical reactions like rusting proceed faster. But are you sure that you'll get the same result if you repeat the experiment? What reason will you give if you get the opposite result next time?

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


March 5, 2009

Q. I need to know... will a piece of steel wool rust faster outside or inside?
Please I need an answer quick

Dillion Bdeleted
Student - Isla Nada, California

Pop Bottle Science
 


March 6, 2009

A. Times a-wastin', Dillion. Get those pieces of steel wool into play and let us know what you found. Good luck

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


April 29, 2009

Q. Hi I'm 8 years old ,in the third grade . I'm going to do a science project , do you think the sea water will rust metal faster then salt & hot water. Should I use paper clips nails & pennies. or others

Natalie Cdeleted
student - Orlando, Florida


May , 2009

Hi, Natalie. I have opinions on your methodology: I think you should test paper clips, nails, and pennies -- each in separate jars. And I think you should rethink the hot water; how are you going to keep it hot for the week or so that you should allow for the test? It might be better to use room temperature vs. refrigerator temperature.

But I have no opinion on the results you'll get -- you'll get what you get. And what you will get is the correct answer.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


December 6, 2009

Q. Hey, I found your site while looking for information on my sister's science project. She is doing "what will rust". we took three plastic containers and filled them all with 1/4 cup of water. then we took two of the three and put 1 teaspoon in them and then capped one of the two with salt. we put 1 of the following in each one of the containers, a piece of a plastic fork, rubber band, penny, dime and also a nail... about how long do you think we have until something will rust.. since we only have three day till the due date? oh and we also set them in the window sill so that the light may reach them and so far the only thing that has really happened is that the ones with salt have formed bubbles on some of the objects.
please as soon as you could answer the better it would be thanks so much for you time and help,
brandy holley

brandy hdeleted
student - nebo, north carolina


December 7, 2009

A. Hi, Brandy. Coins and nails and plastic forks and rubber bands would not be very useful if they rusted in minutes or hours. 3 days should be enough for a plain steel nail to show early signs of rusting.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


March 31, 2010

Q. My name is Luis and I am 10 year old. I am doing a project about whether metals rust faster in water vs. salt water and why. I need some information about metals. The information that I found when I look on internet is difficult for to understand for me. I need some vocabulary more easy for my age. I will get on line with my mom so she can help me.
Thanks

Luis Gdeleted
Questions about my project - Gainesville, Florida


April 1, 2010

A. Hi, Luis. First, I feel you should not be browsing the internet, but instead getting help from a librarian at your school or town library to locate an age-appropriate science book.

Why? Because the internet is a gigantic disorganized mess :-) You are wandering from lecture hall to lecture hall, hearing stuff that was intended for high schoolers, and stuff that was intended for bridge designers, stuff that was intended for post doctorate corrosion engineering students, and stuff that was intended for homeowners dealing with rusty water.

You need a book that teaches you how to do science projects and why. You need to find something that details how to conduct an experiment, and then you need to do the experiment and have some confidence in your results. Once you are sure that your results are substantial, not random, then you can try to account for them. Good luck.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


April 25, 2010

Q. I'm in the eighth grade and my experiment is testing rust on nails in pure water, tap water, ocean water and water with 50 grams of added salt. So far my experiment has been successful, with tap water with the most rust, but I'm having trouble identifying permanent rust and surface rust. My nails are completely submerged in water. I wanted to ask if I would get faster results without completely submerging them and whether I should have been stirring up the water to allow oxygen to mix with the water

Thanks so much this site helps.

hope you have an answer for all my questions

Darcy Sdeleted
- Sydney NSW Australia


April 25, 2010

A. Hi, Darcy. Stirring is okay but it adds an additional variable, so I wouldn't do it. There might be faster rusting at the surface if the nails were partially submerged, but again it's another complicating variable. It depends on what you want to do.

I don't agree with or understand this distinction between "surface rust" and "permanent rust", although I agree that rusting can vary from minor to catastrophic.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


October 4, 2010

Q. I am doing a project called, the effect of salt concentration on rust. I am in 7th grade. but what types of things should I research to form my hypothesis? if we are going to take water and add different amounts of salt to them and then my control is just plain water, and we are going to put metal in it (not sure yet if it will be a nail, paperclip, wire, etc.) I don't know what to research! Thanks in advance.

Emily Ydeleted
student - Baltimore, Maryland U.S.

October 5, 2010

A. Hi, Emily. I'll bet your librarian can find age appropriate books or chapters of books in minutes. The principle is that hopefully you will be able to demonstrate that the amount of corrosion is related somehow to the salt concentration. So your hypothesis can be: "The more salt, the more corrosive water is to metal" or "The less salt, the more corrosive water is to metal". Good luck.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


October 21, 2010

A. The tap water (fresh water) has more effect than sea water.
Sea water will lead to "general corrosion" due to its good conductivity.

Fresh (tap) water will lead to (local corrosion) due to less conductivity

ahmed nasr
- suez-egypt

December 10, 2010

Q. I am thinking about doing this science fair project. Does any one have good websites that list information about this topic or some advice on how to get fast results? I only have about 2 months to do it. Or if you think I don't have enough time, are there some good projects that could also get me to state science fair? We are "discouraged" to grow bacteria, do things with people, or invertebrate and vertebrate animals.

Ashley S.deleted
- Royal, Iowa, U.S.A.

March 9, 2011

Q. Hi I am in Grade 9. I am doing an experiment with electric current and salt water. I attached a beaker of salt water to my circuit using alligator clips placed in the water. When I stopped the current, the alligator clip was completely rusted and the water was turned yellow because of the rust. I was wondering whether electric current increases rate of rusting in salt water.

Cece Kdeleted
Student - toronto ontario canada

March 10, 2011

A. Hi, Cece.

Your wording may not be precise, but your finding is correct. Yes, applying electricity can greatly accelerate the corrosion. But rather than asking, you should make it your hypothesis that applying electricity increases corrosion, and then do some experiments demonstrating it. Low voltage batteries only (1-1/2 volt), because electricity plus water is very dangerous.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


March 26, 2011

Q. Hi I'm in 5th grade and our class is doing a science fair. My science project is putting 3 different kinds of metal: iron, copper and aluminum in 3 different kinds of solutions: tap water, vinegar, and salt water and to see which one rusts the fastest. What should my hypothesis be? Also should I put less metals, solutions or should I not change anything at all? This is due in 1 week so please answer ASAP. Thanks in advance.

Niralee S.deleted
student - Taipei, Taiwan

March 28, 2011

Hi, Niralee.

Well, you have an experimental procedure established (the 3 metals you have selected and the 3 different solutions), but you have no hypothesis yet, and that's a bit backwards because the experimental procedure you propose is supposed to be designed to try to prove or disprove your hypothesis. To better understand the problem, suppose I told you I'm going to ride my bike around the block 3 times clockwise, then walk around the block 3 times counterclockwise -- and I then ask you what my hypothesis about that travel should be. It could be anything: that bike riding made me more dizzy? that walking took less time? that going clockwise resulted in fewer mosquito bites?

Here's one possible hypothesis for you: "Iron will corrode faster than copper or aluminum whether tested in tap water, salt water, or vinegar". Good luck. But, next time, you need the hypothesis first :-)

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey

Metal Samples


June 19, 2011appended

Q. Hi, my name is Braydee T. I live in Australia.
I am in year 9 and recently conducted an experiment on whether salt water or distilled water produces more rust on steel wool over a week. We took observations every day for 5 days and each day the steel wool in the distilled water had more rust on it than the steel in the salt water. Also, the salt water turned a cloudy green colour.
If you could please explain why it would be greatly appreciated. Thanks:)

Braydee T.deleted
student - Perth, Western Australia, Australia

November 2013

A. Hi Braydee. What you can probably say is that distilled water causes steel to rust faster and more than salt water. You can pass the salt water remains though a coffee filter and see what color the water is then (clear, cloudy, rusty, or green) which will tell you whether the green color is some sort of precipitate or a soluble salt. I'm not sure that you can say anything further without more experiment, but proposing what the next experiment could be might get you extra credit.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey


November 18, 2013

Q. Hey, I'm in sixth grade and I want to know how long does it take for a nickel to corrode in saltwater and tap water?

Christopher H [last name deleted for privacy by Editor]
- College Park, Georgia, America

November 22, 2013

A. Hi Christopher. The idea of these science projects is to actually do them and to learn for yourself from doing it yourself rather than depending on conventional "book knowledge" -- which can be wrong. But don't be disappointed if you see no corrosion of the nickel in either saltwater or tap water without the time to complete your assignment.

You might learn, as one possibility: "Nickel is quite corrosion resistant and did not visibly corrode in either salt water or fresh water in the one week time frame of this experiment". Good luck.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Brick, New Jersey

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