Every now and then someone sends me an e-mail that claims the difference between Coke and water, and how bad Coke is for you. To illustrate that, the e-mail points out that Coke can be used to clean a toilet, help remove a rusty bolt or remove blood from a highway accident.
One item, in particular, caught my eye:
The active ingredient in Coke is phosphoric acid. Its pH is 2.8. It will dissolve a nail in about 4 days.
This one entry screamed that it just can’t be true. Let’s examine it:
“The active ingredient in Coke is phosphoric acid.” – An active ingredient is defined as: “a component or mixture that performs the function of the product”. What exactly is the function of Coca-Cola? According to the Coca-Cola web site, Coca-Cola does not perform any function, other than to provide “true refreshment” (a bit vague of a function if you ask me). To that end, I would be inclined to believe that the sugar and water in Coke are more likely to be called “active ingredients” than phosphoric acid, although phosphoric acid does contribute to the taste of Coke.
“Its pH is 2.8.” – Its pH may very well be 2.8, but with the amount that is actually in a can of Coke, I’m sure that the other ingredients buffer it. Ever drink a glass of wine? Good quality wine has a pH of about 2.9. pH of 2.8 is about the pH of lemon juice. A pH of 2.8 might make your mouth pucker, but it won’t hurt you.
“It will dissolve a nail in about 4 days.” – What will? Based on elementary school English, the subject of the first sentence is phosphoric acid. The “it” in the second and third sentences are pronouns referring to the phosphoric acid in the first sentence. That means that phosphoric acid will dissolve a nail in about 4 days. What does that have to do with Coke? Is it the only ingredient in there? I have hydrochloric acid in my stomach with a pH of 2…if I hold a nail in my hand for four days, will it dissolve?
So, now that we have dissected it, lets go ahead and test it!
Introduction
The purpose of this experiment is to test the validity of the “The active ingredient in Coke is phosphoric acid. It’s pH is 2.8. It will dissolve a nail in about 4 days.” statement that is found in several e-mails making their way around the Internet. Specifically, will a nail left in Coca-Cola dissolve in about four days (96 hours).
The first thing that came to mind is that the e-mail did not specifically say which variety of Coke it was talking about. In the absence of a particular variety, I would assume that the plain old Classic Coca-Cola variety would be assumed. To be on the safe side, I included four of the most popular varieties of Coke: Classic Coke, Diet Coke, Vanilla Coke, and Cherry Coke. For good measure, I also included Pepsi, Dr Pepper, Sprite and some genuine, fresh, New York City tap water (it’s won taste tests!).
The second thing that came to mind is that the e-mail did not specifically say what kind of nail the nail is. It is steel? Brass? Lead? Keratin? I decided that the two most popular kinds (and the kinds most likely to be found in my apartment) were the standard steel, “wall mounting” nail, and the keratin based fingernail. I rummaged around my toolbox and found the former. The latter was a bit harder to come by. I had just cut my nails earlier in the week, and didn’t have much growth to make an effective experiment; however, my toenails were due for a trimming. Only problem with toenails is that when clipped, they have a tendency to fly across the room at a high rate of speed. This made gathering them up a bit of a challenge, but testing the veracity of the email claims are my contribution to society, and as such, a little discomfort would have to be endured.
The following table details the list of equipment used in this experiment. I’ve also included the ingredients listed for the sodas used in the experiment.
| Quantity | Item |
|---|---|
1/4 oz. | Coca-Cola (Classic) |
1/4 oz. | Diet Coke |
1/4 oz. | Vanilla Coke |
1/4 oz. | Cherry Coke |
1/4 oz. | Pepsi |
1/4 oz. | Dr Pepper |
1/4 oz. | Sprite |
1/4 oz. | NYC tap water, unfiltered, straight from the tap |
9 | glass spice jars with tops |
9 | steel, 1″ nails |
9 | toenails of various sizes from Josh |
1 | 8x Carl Zeiss loupe (for examining the results) |
1 | Revlon toenail clipper (for clipping the toenails) |
3 | Paper towels (for general spills, toenail clippings, etc.) |
1 | small glass food preparation bowl |
The following photos were of the initial setup:
All equipment
Keratin nails
Steel nails
Measuring out the Coke
Pouring the Coke
The nails just before submerging
December 14, 2003
Each spice jar was labeled with the name of the liquid that it was to hold. 1/4 oz. of each liquid in the experiment was measured out and poured into the corresponding spice jar. A steel and keratin nail were randomly chosen and assigned to each jar. Each jar, steel nail, and keratin nail were photographed. The steel nail and keratin nail were examined under the 8x loupe and notes were made about their appearances.
At 2100 hours (Eastern Standard Time (EST)) the nails were put into the jars, and the tops were put on the jars. The tops were not screwed on tightly, but rather left a little loose to allow some gas to escape.
I will check on the progress at 2100 hours tomorrow.
December 15, 2003
At 2100 hours (24 hours after starting the experiment) the nails in each jar were photographed, examined with the 8x loupe and compared to the control samples and the notes made at the start of the experiment.
Both the steel nails and the keratin nails from the Coke, Diet Coke, Vanilla Coke, Cherry Coke, Pepsi and Dr Pepper showed no signs of change, other than a darker color. The steel nail and keratin nail in the Sprite showed no sign of change other than a slightly duller color. The steel nail in the tap water showed some signs of surface rust, with the water near the nail a medium rust color. The keratin nail in the water showed no changes.
I will check on the progress at 2100 hours tomorrow.
December 16, 2003
At 2100 hours (48 hours after starting the experiment) the nails in each jar were photographed, examined with the 8x loupe and compared to the control samples and the notes made at the start of the experiment and after 24 hours.
Both the steel nails and the keratin nails from the Coke, Diet Coke, Vanilla Coke, Pepsi and Dr Pepper showed no signs of change, other than the darker color seen yesterday. The steel nail and keratin nail in the Sprite showed no sign of change since yesterday. The steel nail in the tap water showed more signs of surface rust, about 50% of the outside covered with it. The water near the nail was a deep rust color, and there were these little rust colored specks all over the bottom of the jar. The keratin nail in the water showed no changes.
The steel nail in the Cherry Coke showed some signs of a slight corrosion on about 1/8 of the shaft of the nail. It was only evident on one side of the nail, and I’m not sure whether this was the side of the nail that was in contact with the glass jar or not.
I will check on the progress at 2100 hours tomorrow.
December 17, 2003
At 2230 hours (73.5 hours after starting the experiment) the nails in each jar were photographed, examined with the 8x loupe and compared to the control samples and the notes made at the start of the experiment and after 24 and 48 hours.
Both the steel nails and the keratin nails from the Coke, Diet Coke, Vanilla Coke, Pepsi and Dr Pepper showed no signs of change, other than the darker color seen the past two days. The Diet Coke steel nail seems to be lighter than the other cola nails, but it is still darker than the control nail. The Sprite liquid has turned a slightly green/yellow color, and the keratin nail shows a slightly green/yellow tint. The steel nail in the Sprite looks dull, but otherwise, unchanged. The steel nail in the tap water showed more signs of surface rust, about 75% of the outside covered with it, but there is a section that has no rust, again, I assume this is where the nail is in contact with the glass. The water near the nail was a deep rust color, and there were these little rust colored specks all over the bottom of the jar. The keratin nail in the water sports a rust colored hue, but otherwise, appears unchanged.
The steel nail in the Cherry Coke does not show the signs of the slight corrosion mentioned yesterday, and looks very similar to the other cola nails.
I will check on the progress at 2100 hours tomorrow.
December 18, 2003
At 2330 hours (98.5 hours after starting the experiment) the nails in each jar were photographed, examined with the 8x loupe and compared to the control samples and the notes made at the start of the experiment and after 24, 48, and 73.5 hours.
This is the official end of the experiment since the e-mail said the nail would dissolve in Coke after four days. It has been four days plus 2.5 hours since the experiment began.
The keratin nails from all of the soda’s showed no ill effects. They did turn the color of the soda and were soft, like after you take a shower, but overall, they were unaffected.
The steel nail results are as follows:
| Jar | Result |
|---|---|
| 1. Coke | It is dark and rough to the touch. |
| 2. Diet Coke | It is smooth and is rusted on 75% of the shaft. |
| 3. Vanilla Coke | It is smoother and slightly lighter in color than that of the Coke nail. |
| 4. Dr Pepper | It is smooth and has an even, dark luster throughout the nail. Of the cola nails, this one seems to be the most consistent in its feel over the whole nail. |
| 5. Pepsi | It has the same color and touch as the Coke nail. |
| 6. Sprite | It is dull compared to the control nail. Otherwise, unchanged. |
| 7. Cherry Coke | It is slightly darker than the Vanilla Coke nail, but not as dark as the Coke or Pepsi nail. Has a slightly rough touch to it. |
| 8. Water | It has rust over 100% of it. Some patches are darker than others. |
| 9. Control | Nail is shiny and has the same color and touch as a nail straight from the package. |
All steels nails after experiment is over
Now that we know what happens to the outside appearance of the nail, we now need to test its structural strength. The only test I could think of that I could do with my limited resources was to try to hammer each nail into some wood.
The results of the hammer and nail test were the same for each nail. Each nail had no problem being driven into the wood. Each nail took about four hits to be driven halfway into the wood (not including the four times I hit my thumb…the things I do for science!).
Nails in wood
Conclusion
As I suspected, no nail of any kind was dissolved by any of the sodas.
At least that entry in the e-mail is false. Perhaps I should tackle some of the other entries…
Bibliography
The Coca-Cola Company
http://www.coca-cola.com/
Science Is Fun in the Lab of Shakhashiri – Chemical of the Week – Phosphoric Acid
http://scifun.chem.wisc.edu/chemweek/H3PO4/H3PO4.html
Gondar Design Science – Acids and alkalis—the pH scale
http://www.purchon.com/chemistry/ph.htm
Not nails! Try teeth. Get the kids baby teeth or extracted wisdom teeth and try your experiment again!
im doing nails for my scinec project
it seemed interresrting 
Iron nails rust in Coke. Steel nails do not.
Thanks for the detailed notes! I was going to try this for a fun science experiment in my 5th grade class, but after reading this and other info I see it doesn’t really work! Though it might be good for kids to see you can’t believe everything you get in an email… <img src="http://joshmadison.com/images/smileys/wink.gif" width="19" height="19" alt="wink" style="border:0;" />
THANK YOU SO MUCH!!!! THANKS!! I’m so sick of people telling me coke will dissolve a nail. You are awesome! Great project as well!!
Hi,
From what I understand it is necessary to use iron nails without a coating. Nearly impossible to find in hardware stores today. Need to find iron from another source.
I am doing this for my 8th grade Science Fair and I already have my report due tomorrow so it is too late to turn back now, but I wish I would have known this earlier to prove that Coke can NOT dissolve a nail!
Cars and television don’t help either, but I’m only testing whether it can dissolve a nail, not trying to save society in general.
good one josh, I agree, but coca cola can have a negative effect on you also, especially diet coke because of the aspertame in it, aspertame is used in many weight gain formulas and makes you crave more, and in drinking more it adds more calories, then there’s to many calories, then you get fat!!!
I always thought that a nail would disolve in coke but i guess not.This will bw my topik 4 the science faire at my school if a nail disolves in coke. I will do a teast like yours and see if what i get was like youres.
Thanks! this experiment will help me on my science fair. It's about what coke can and can't dissolve.:)
p.s. BLOOP
what do you do for the control nail?
i am doing an experiment on "which soda will dissolve a nail the fastest?" i am sure it will be coke but i cant use a steel nail because it obviously wont dissolve. Should i try a pure iron nail with no coating???
That seems to be the consensus. If I were you, I'd actually do the experiment with both, and any other type of nails you can find.
I doubt you will find the iron nails you are looking for in a hardware store. Maybe an antique shop… they may have the square nails of yesteryear.
I am also wondering if a drycleaner's type metal hanger might be an adequate substitute cut into short lengths. The little bit of coating or paint could be easily sanded off or just left for the acids to do the job…
The other thing I wonder about is the amount of soda and the freshness of it… perhaps a larger amount would not be neutralized by the chemical reaction OR swapping out the old soda on a daily basis???
Actually, i did the same project to test it except i used a nail, PENNY, AND HUMAN TOOTH into plain coke for about 14 whole days. Every 12 hours i had to check and really nothing happened. BUT the hard part is getting it all together. I am still working on that…
came on this site for backround info
i am doing a project on the effct of coke !!! should i do stell nails or human nails ? which one will give the bezst result ?
You did it wrong, i did the same and coke did dissolve the nail josh, if you wanna do a experiment do it right BOOOOOOOO!!!!!
stfu
no because they will be old, and teeth rot sfter a cerain emout of time.
lucky!!!
thanks this helped alot i was doing a science fair project on this but it only rusted
im confused because some websites say that nails will dissolve in a glass of coke in about 4 days but some say it wont. i am doing my science project on this and i tried the nail in coke and sprite but that was a long time ago and it didnt work.
I have 3 days to finish my project. I started 3 days ago. I’ve read that the nail will dissolve in 4 days. Is that true? i need to know ASAP!!!! Or else i will get a bad grade.
PLEASE HELP ME!!!!!
you're grade is toast!
Oh this was great – a true, practical, American way of making science.
That's we Old Europe need the US!
: )
I'm doing this for my Science project @ school…. It blew every one's mind, and it worked
Define "it worked".
Wow, I'm axially doing that for my science projet, it rock's. I didn't no anyone els has ever done it, thought I was the first, bummer
Thanks, this is hilarious and it made my day. I was actually searching for a way to very selectively dissolve paper, but I took a moment to read your blog entry.
by nails it means your nails in your hand.
I am starting to think that the "Coke" required is not the trademark variety, but the illicit type imported from warmer climates
Thesse nails are all galvanised or coated. You want to use "bright common" nails available at any hardware store.
The main component in Bright Common nails is Iron which oxodises the iron, I would be interested in your results if you redo the experiment with common nails, I'm sure you will have a somewhat different result.
My son is doing this experiment now for his science fair project. He used a steel nail (non-galvanized). It has been 10 days and the nail has darkened (black comes off on your fingers) and there's minor corrosion. A classmate of my husband's said they did this experiement with coke and a steel nail about 23 years ago and it apparently dissolved the nail within 24 hrs. I guess phosphoric acid in coke was a lot higher then. As far as the work involved goes, you still have to check the progress each day, photograph the nails and log the information no matter what the result. It's still just as interesting to disprove something as it is to prove something.
what is dirt coke
Thx for the comment "Nameless Chicken" me and my friend are going to use the teeth and sugar thing for a science project.
Phoroshoric Acid – Fact or Fiction? The active ingredient in Coke is phosphoric acid. It’s pH is 2.8. It will dissolve a nail in about 4 days! Wow! Jared Brown from Richland, Washington wrote this letter concerning this “rumor”! “What you heard isn’t true at all. I’ve been doing a science project on the effects of phoroshoric acid and I tried to dissolve egg’s and nails, even a steak. Nothing was dissolved. I put a nail in a bowl of Coke and changed the coke everyday for 3 weeks. Nothing happened. The nail didn’t flynch in size or weight. It just turned a really dark cool brown color.”Aw oh Jared, Libby from West Frankfort IL doesn’t agree with you! Libby writes; “I just read the Coke tips page and Jarred (sp) said Coke will not dissolve a nail. I have tried the same experiment and learned that if you want it to dissolve you must use an iron nail without a coating. Iron is very reactive with acids. Also, you need to put it in a 2 Liter bottle and reseal it because it is actually the carbonic acid (from the CO2 -carbon dioxide) that dissolves the nail not the phosphoric acid. If the Coke is open then the Carbon dioxide escapes and will not be as effective.” Thanks for setting us straight Libby!
My son is in 5th grade and we just completed an experiment on oxidation and the rusting of nails in 6 different liquids. One of the liquids was Coca Cola. We baked 6 iron nails for 15 minutes to remove the coating. Our experiment was recorded over 6 weeks. Coca Cola had the MOST rusting of all the liquids. Two of our other liquids were salt water and well water. We found Coke to disolve the nail within just a few days. Our conclusion was that with an uncoated nail, Coke can cause a tremendous amount of rusting!
I've done the teeth experiment (only with Coke classic) – I left one of my baby teeth in the Coke until there was nothing but an almost dry syrup and a lump (more than a month). When I washed it, there was the tooth!
Recently a dentist explained to me why Coke (and virtually all other sodas, sports drinks and many fruit drinks) are bad for the teeth. Any that contain phosphoric acid (or orthophosphoric acid) cause the same problem. Phosphorous is required in small quantities by the body, but large quantities would be toxic. Phosphorous cannot be excreted by the urinary tract, so it must be excreted in the feces. To do this, it must be a solid – and the body requires calcium to make the insoluble calcium phosphate. If the diet has insufficient calcium to match the amount of phosphoric acid, then the body takes the calcium from the teeth or bones to excrete the poison. As the bones are more important to the body than the teeth, the body takes the calcium from the teeth first.
The teeth virtually erode from the inside out. As a person who used to drink between 6 and 8 quarts of coke a day, I can tell you that my otherwise healthy teeth began to break for no apparent reason. This was when the dentist explained the real facts.
I love Coke, but daren't drink it or other drinks containing phosphoric acid. If you do, then make sure you have plenty of calcium in your diet!!
I rather enjoyed the detailed experiment. For those who have tried it longer like for a month and DO show dissolving action, I would be interested to see if this would happen even in regular tap water as well simply because of the rusting process. Also, to the one who says "dirt" coke is bad because it "rusts" a nail…do not forget that Coke DOES contain water and water did cause the nail to rust as well. I'm glad to finally have this discussion in general proven false and laid to rest.
i think this project thingy should have been longer, therefore maybe dissolving the nails in like 5 months!! you didnt prove anything and i think it would dissolve at least half a nail in like maybe 10 months, but that still is proof that coke CAN dissolve a nail. i have to agree with R.T. he(i think R.T. is he) he dissolved at least .1 gram(s) of a nail in coke!
you are awesome monkie-inator!!!! well, because i agree with you and you are my sis. ya, the experiment should have gone a LOT longer. c u l8r!
try it using an uncoated iron nail and see if you get different results.
does the coke dissolve the nail or what i need to know left my experiment to the lastinute got 1 week :/
Thanks so much for doing the experiment on the nails with the coke because it showed actual results and not just your opinion on what might happen, which is obviously what the person or people who started this myth did.Thanks again,now I know.
Loved the experiment, Josh!! Thank you so much!!!!
Great experiment for my fourth grade class!
I don't know how much phosphoric acid is in cola. On this side of the Herring Pond I've known about and used phosphoric acid for at least 50 years. The main use has been as a rust converter, and you know when rust, iron oxide, has been converted to iron phosphate because it turns black. Looking at some of the nails in the test look about the same colour as the steel does after it was converted. I am not a chemist,so I don't know the strength of the acid I've used, compared to that in the beverage, "My" rust converters take about half an hour to work, and, generally speaking, you can paint straight over the surface [with the right paint] and be pretty sure it'll be a long time before you're troubled again/.
Duh, using a steel nail isn't gonna help much. The typical query is whether coke can dissolve an Iron nail. Obviously you need more than the minimum amount of coke possible to cover the nail. Coke can dissolve an Iron nail in 4 days, given a heat source and a regular change of coke in the coke bath. thx.
im doing this and it is an easy project
science exp for Beano
Youre an idiot. Does coke really have to be able to dissolve a nail in four days for you to figure out that it's TERRRRRIBLE for you health. Moron.
I believe your suppose to put a nail in a 2 liter bottle of Classic Coke….
AWESOME!!! but coke can be a really good factor because nurse's and doctor's @ hospital's use it to settle your stomach if your having problems.
[...] read about his experiment go to his blog, “Will Coke Disolve A Nail” Experiment. Thanks, [...]
i agree any places to go?
i know right!!!
yeah it is a great project
u realize that coca cola changed their formula so it would no longer dissolve nails and clean drains?, was kinda bad for profit
what is then?
i am doin this for a 7th grade 1.
cool!!
yea…
Oh, the claim being tested was shown to be false, so the obvious ploy is to use the tried and true startegy of changing the subject.
hey not tryin to do anythin wrong, but i am doin a similar project. but instead i have 3 nails 1 pepsi, 1 serri mist, 1 bottle water, and the nail in the wateer when i look at it the nail as bubbles all over it. the serr mist as no bubbles on it and the pepsi i cant see through it and so i dunno what is happin to the nail, all i know is when i put it in it almost exploded.email; me at rawrlovez@gmail.com plz for any questions or want to be friends and i am 13
yah but it would still be a good example.
got that right!
the email I received about phosphoric acid in Coke claimed that "phosphoric acid" would dissolve a nail not the coke with phosphoric acid in it. It was merely pointing out that a chemical compound "phosphoric acid" that was capable of dissolving a nail could also be found in Coke, albeit in a much lesser amount.