Introduction: Fun With Acid!

Picture of Fun With Acid!

I'll show you something neat you can do with some easy to obtain acid.

Step 1: Supplies

Picture of Supplies

You'll need the following:

- Muriatic acid (hydrochloric acid)
You can find this at your local hardware or paint store.

- Small glass

- Some shiny pennies
Only pennies from 1982 and newer will work.

Step 2: Grind Away

Picture of Grind Away

File away some of the copper on the side of the penny you don't want to keep.

In doing so, you'll expose the zinc inside.

Step 3: Now for the Bubbly! (and an Explanation)

Picture of Now for the Bubbly! (and an Explanation)

Put the penny in the glass with the exposed zinc facing up.

Next, pour in just enough acid to cover the top of the penny.

Leave it for several hours or overnight.

So what's going on in the glass?

The composition of U.S. pennies changed in 1982.

Before 1982 (for about 20 years), pennies were an alloy of about 94% copper and 6% zinc.

The increasing cost of copper made this impractical. Therefore, some 1982 pennies and all
pennies produced after that time have a pure copper shell with a zinc interior.

The new pennies contain only about 2.4% copper and weigh 2.5 grams as opposed to the 3.1-gram weight of the older type.

Zinc is a more active metal than copper. In this experiment, we see that zinc will react
with acid to produce hydrogen gas:

Zn(s) + 2 HCl(aq) => ZnCl 2(aq) + H 2(g)

The hydrogen gas generated by the reaction will bubble up because it is less dense
than the penny and the acid solution.

However, towards the end of the reaction some bubbles of hydrogen may adhere to the copper or be trapped inside the shell. If this occurs, the combination of copper and hydrogen gas may be less dense than the acid solution and what is left of the penny may float!

Step 4: The Next Morning...

Picture of The Next Morning...

After the acid has finished reacting with the zinc, you will be left with a thin copper foil and a copper shell of a penny only one thousandth of an inch thick!

The shell will be very fragile, so use tweezers or a cotton swab to pull it out of the acid.

You can rinse the shell in the sink with some tap water.

NEVER, NEVER pour water into acid. Dispose of the acid by pouring it in the sink and then rinsing it down with water.

You can also neutralize the acid with some baking soda.

Step 5: Clean It and You're Done!

Picture of Clean It and You're Done!

Now carefully clean the inside of the shell with a cotton swab. Be sure to place it on a flat surface so you don't bend it.

Now you're done!

You can use the penny shell to hide a dime in for an oldie but goodie magic trick.

More information can be found in these fine books on

Experiments That Explore Acid by M.Gutnik

365 Simple Science Experiments with Everyday Materials

Classic Chemistry Experiments by Hutchings


Magnelectrostatic (author)2007-08-23

Why shouldn't you put water in acid? That should just dilute it. Also would an aqueous solution of hydrochloric acid work?

The reason to add acid to water is that many acids boil at low(ish) temperatures and heat up when combined with water. If you add acid to the water, you end up diluting the acid out very quickly, raising its boiling temperature closer to that of the water. Hot water with a little bit of acid in it is no big deal. If you add water to acid, the first few drops of water mix up and create heat in a very concentrated acid mixture. This can boil or fume or worse. Hot acid with a little bit of water in it is a problem.

laci37 (author)The Real Elliot2009-01-16

HCl(hydrogen-chloride) is not a liquid, it's a gas, hidrochloric acid can be mixed safely with water since it's the solution of HCl, but do not try this with sulfuric acid, because the water boils because of the exothermal reaction and the acid can go out of the container. If you want thin sulfuric acid you need to mix aysmall amount (few drops) of sulfuric acid with much water, because the water absorbs the heat of the reaction.

soapmaker72 (author)laci372015-08-03

Certainly, adding hydrochloric acid to water is far less dramatic. Still I notice a significant rise in temperature by adding 30+% into water. If that water is already 90 Celsius then you could get a POOF of HCl vapors in your face from the exothermic dilution.

Adding water to HCl is an exothermic reaction. If you add water to the acid there's a chance that it will splash up and get you on the skin or in your eyes. You always slowly add the acid to water. Not water into acid.

lemonie (author)skegger2007-08-24

Yes, you're right. Concentrated sulphuric is quite exothermic, you need a bit of stirring even if you are doing it in the right way L (Hydrogen-bonding)

Grimling (author)2007-08-23

When i readed : Fun With Acid! , i was really hoping it would be an instructable about our good friend , Lycergic Acid Diethylamide :p Nice Instructable anyhow

minerug (author)Grimling2008-03-10

what is 'Lycergic Acid Diethylamide'?

mannys9130 (author)minerug2008-06-11

lysergic acid diethylamide also known as LSD, is among many hallucinagens. LSD was created by albert hoffman. look it up on wikipedia, it'll tell you all about it.

minerug (author)mannys91302008-06-12

lol, 'daddy, that funny chemical made me see things'......

FrozenFire (author)minerug2010-07-27

I've seen things! I've seen them with my eyes! I've seen things, they're often in disguise!

x z i t (author)mannys91302008-07-01


x z i t (author)x z i t2008-07-01


a powerful hallucinogenic substance. (also known as, "gettin' high, dude")

Supreme_Angler (author)Grimling2008-02-15

I love that friend.

Kataze (author)Grimling2007-08-23

Ah, good times.... XD

lemonie (author)Kataze2007-08-25

Oh yes L

Silas (author)Grimling2007-08-23


macingtosh (author)2010-07-19

does it wok with old muratic acid because ive had some in my garage for about 3 years and also how can you trick someone if the dime dosent have the other side of the penny

Kiteman (author)2007-08-23

"Don't breath the fumes" No problem breathing the fumes - they're competely non-toxic. They do, however, go bang - It's hydrogen. Leave an inverted tub over the penny to collect the bubbles, you can celebrate getting your (quite excellent) penny shell by lighting the hydrogen!

lobo_pal (author)Kiteman2009-09-20

I depends on the molarity of the acid, HCl produces Chlorine gas naturally, which is one of the most notorious killing devices known to man.

Kiteman (author)lobo_pal2009-09-21

Not when reacting with metals: HCl + metal -> metal halide (salt) + hydrogen gas.

lobo_pal (author)Kiteman2009-09-21

Yes, but any unreacted HCl will still put out chlorine gas, and since these are amateur chemists they probably won't balance the moles, and while he gives measurements, not everyone will follow these.

PKTraceur (author)Kiteman2009-07-24

Kiteman, I thinks thats the first time you've had fun on 'Ibles...

PKTraceur (author)Kiteman2009-07-24

Fine, fine, but the first time having fun with chemistry, and not the social kind. Plus, I haven't been on ibles for about 4 months...

laci37 (author)Kiteman2009-01-16

After the first smell you will consider berathing it again because the hydrogen-chloride goes out of the heated solution, and it is irritating.

NK5 (author)Kiteman2007-08-23

I was referring to the fumes of the muriatic acid, actually. Those are quite noxious.

mellis1995 (author)2009-09-11

wow that is really cool would it work with 1p and 2p coins to

sharlston (author)2009-08-08

nice ible its really cool and well written :)

dhdishner (author)2008-09-24

Put it in a plastice 20oz coke bottle (1/4 way full) add a couple foil balls and close it up..... mustard gas bomb.... and you all say you cant have fun with acid!!!

laci37 (author)dhdishner2009-01-16

That's not mustard gas! Do NOT try to make mustard gas becasue that's NEUROtoxic(it affects your brain). With this bomb the sound of the exploding hydrogen or your hurting lungs will affect your brain not the gas...

M4industries (author)laci372009-07-07

A) What you described is a felony to detonate in public areas. B) Neurotoxins arent something many people can make in their backyard.

Sunny124613 (author)2008-07-11

how can you have fun with acid? It burns....

mspark400 (author)Sunny1246132008-09-16

how can you NOT have fun with acid? IT BURNS!!!!! cheers, (and safety) mspark400

Sunny124613 (author)mspark4002008-09-30

yah,your right.I have GOT to try it on my bros...... mwahahaha....

dombeef (author)Sunny1246132009-04-26


M4industries (author)dombeef2009-07-07

I've gotten it on my skin before, it itches.

dombeef (author)M4industries2009-07-07

Oh ok man did it burn?

M4industries (author)dombeef2009-07-07

Stung a little bit, felt like touching a stinging nettle plant. I only got burned because I was stupid enough to forget about washing it off.

lil_pyro (author)mspark4002009-05-18


Project_Nightmare (author)2007-08-24

If you mix HCl with lye (NaOH), you'll get salt and more water. But who knows how violent the reaction will be

Derin (author)Project_Nightmare2008-05-13

and poisonous fumes

"If you are cordless,you are free.But if you are corded you are chained to a socket."Sir Derinsleep

laci37 (author)Derin2009-01-16

There are no poisonous fumes if you mix the hidrochloric acid with enough water and it won't boil, else some HCl can be produced, so do it outside


codongolev (author)2008-10-12

you could just file a small hole at the edge and end up with a hollow penny.

instructors (author)2008-10-10

You cude make your own scotch an soda (magictrick) with this method!

dhdishner (author)2008-09-24

Also had another thought. You could take the shell of that penny and glue it to another one to make a double sided coin...

PyroMonger (author)2008-02-03

muriatic acid can also be used for acid bombs where you just add foil BUT BE WARNED! it is very dangerous and make sure you do it in a safe place with no cops..I was unlucky to do it with my cousin one time at his new house in a new area and there was an off duty officer at home who heard the loud noise and thought (in his words) that someone was discharging a weapon. he came on our property and started taking my aunt called her link in the S.A.S and got him a hefty punishment for doing that shit without a warrant and he also nearly got a beating from me and my cousin because he was in plain clothes and we didnt know he was a police officer.....nearly threw one of the bombs at him too...on purpose....seriously though careful and take others into consideration when doing explosive experiments...or any for that matter!

mshannon93 (author)2007-09-20

shiniest penny i ever saw

Ohm (author)2007-09-03

If I remember right you can desolve some tin in boiling HCL and use it to coat a penny and then use a burner flame to melt the outer layer of copper and the tin together making a brass penny.

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