The Digital Bits Science Labs are fun science experiments for young children. Kids, make sure you have an adult's permission before trying any of these science experiments.
Digital Bits Science Lab
Science Experiments for Kids, Parents and Teachers
How to electroplate copper
Warning: Copper sulfate is poisonous if swallowed, and the blue color makes it very attractive to small children. Do not leave the crystals or solutions unattended around very young children, who may try to eat or drink them!
Description: Dissolved copper can be plated onto a metal surface using electricity. Learn how electroplating works.
Equipment needed:
Copper Sulfate. This is one of the most soluble copper compounds, it makes bright blue crystals and dissolves fairly easily in water. You can buy it in hardware stores in several forms, the form I found was Roebic Root Killer (used to clear roots out of sewers and septic systems).
Click the photo to view the larger-sized picture.
A small DC power supply. A “wall-wart” power adaptor like this one works fine. I expect that pretty much everyone has at least one or two of these around, orphaned when the electronic gadget that it went with broke down. This power supply came from . . . from . . . well, to tell you the truth, I don’t know what it came from. All I know is that, whatever it was supposed to provide power to, we don’t have it anymore.
A couple of “alligator clips“, to put onto the wires from the power adaptor. These cost about 50 cents each at the hardware store.
Wire stripper
(optional, if you’re handy with scissors)
A screwdriver, that matches the type of screws on your alligator clips.
A small plastic or glass container (something small and disposable, like a small jelly jar or a yogurt cup, is good)
A chunk of copper that will fit easily into your container, and that is thin enough to clip on an alligator clip, and long enough to stick out of the container (a piece of heavy copper wire, or a copper sheet, are both good. You can get these at any hardware store). This will be one electrode of your electroplating cell.
A large steel nail that is long enough to stick out of the container. This will be your second electrode.
A plastic or wooden stirrer for mixing the solution (a coffee stirrer or a wooden skewer are both good. Don’t use a metal spoon to stir it, because it will plate copper onto the metal)
A multimeter, either a digital multimeter
or an analog multimeter
. (It’s optional, you can do the experiment without this, although it does help.)
The Digital Bits Science Lab Experiment:
First, prepare your power supply. Cut off the end that would normally plug into the piece of electronics, and pull the two strands of wire apart.
Strip the insulation off of the ends, and put on the alligator clips so that your power supply looks like this:
Put a spoonful of copper sulfate into the container, add water, and stir until the copper sulfate dissolves.
Put in the piece of copper and the nail, with the ends sticking up:
Now, if you have a multimeter, you can check the polarity of your power supply. Clip the red (+) lead of your multimeter into one of the alligator clips, and the other (-) lead into the other clip. Set your multimeter to read DC volts, and plug in the power supply. If you get a positive reading, then you know that the power supply lead connected to your red multimeter lead is the positive lead. If you get a negative reading, swap the power supply leads and try again.
OK, now clip the POSITIVE lead of the power supply to your copper electrode, and the NEGATIVE lead to the steel nail.
If you don’t have a multimeter, just guess which one is which, we’ll be able to figure it out once we turn it on.
Carefully check to make sure that the two electrodes are not touching each other, ideally keep them about an inch apart.
And now, plug in the power supply and watch what happens over a period of about 10 minutes or so.
If the polarity is correct, then you will get metallic copper plating onto the nail, with maybe a small amount of bubbles forming on the nail as well. Meanwhile your copper electrode will tarnish and turn dark brown or black. If you leave it running for half an hour or so, you should get a deposit of copper something like this on the nail:
If you have the polarity backwards, then your nail will bubble vigorously, and while there may be a thin film of copper on the surface, it will never build up a significant thickness of copper.
What’s happening here?
This is an electrolysis reaction. What we are doing is pumping electrons into one electrode (the nail), while pulling electrons out of the other electrode (the copper). When you add electrons to a copper sulfate solution, the copper sulfate turns to metallic copper and sulfuric acid. The metallic copper is not soluble in water, so it plates out on the electrode where we are adding electrons.
Meanwhile, at the other electrode we are pulling out electrons. This makes the metallic copper there react with the sulfuric acid in the solution to make more copper sulfate.
The overall effect is that copper dissolves from the copper electrode, travels over to the iron electrode, and plates out there as metallic copper.
By adding “smoothing agents” to the solution, it is possible to make the copper plate out as a smooth, shiny metal coating. Similar things can be done with other metals, like gold, silver, zinc, chromium, and nickel. The metal coatings can be decorative, or they can protect the metal underneath from being corroded, or both.
Other articles related to this topic:
- How to make copper metal from dissolved copper compounds
- Multimeter experiment with voltage and current
- Multimeter experiments and introduction
- Multimeter experiments with electricity and water
- Easy electrolysis – how to make your own hydrogen
What are the smoothing agents? I would like to plate an aluminum heat sink in my computer with copper to get it to match some other items but it comes out too rough. What do I have to do to get a smooth mirror finish?
im doing this in the sceice fair at school.
Guys, before you try this and get disappointed:
This is not going to work. You will get a deposit of powdery flaky copper that will brush right off.
Real copper electroplating requires a mix of several different chemicals to create a smooth, even finish that adheres to the target.
This reminds me of trying out copper plating as a teenager. I read all about it in a Ladybird book where it said to use a couple of D cell batteries.
As an impatient teenager I borrowed a car battery from my Dad’s garage.
A tub of copper sulphate was prepared in my bedroom. Two wires were connected to the 12V battery terminals and a 6 inch nail connected to one of them. I lowered the ends of the wire and nail into the solution and suddenly an enormous amount of white smoke was produced.
I ran out of the house as quickly as possible and looked in through the window. I couldn’t see anything because of the thick smoke.
Later on I returned and couldn’t find the wire. Upon closer inspection it had completely melted and there were drips of metal on copper carpet. The current must have been so high that the heat generated was hot enough to melt the wire. I guess I am lucky not to burn the house down.
Funnily enough I haven’t tried copper plating since then.
Actually, this will work. I have done it myself.
I copper plated a quarter.
My copper source was a three inch long piece of copper pipe. I created a little holder out of a paper clip to hold the quarter and to clip onto.
Changing voltage and current will change how fast and even the plating goes.
I used two or three 9V batteries in series to power my project. So I had the same current as one battery, but at 27 volts.
I just used two regular wires with small alligator clips at both ends.
My first science fair project was electroplating copper plates with nickel. I believe we used nickel sulfate from a home chemistry set. My dad and I tried the experiment several times, and only got a brown sludge to form on the copper.
In the end, we got it to work. The trick was to use distilled water only. Our tap water had too many contaminants. Another tip: use steel wool to clean the heck out of the surface to plate.
I, too, would like to know what those “smoothing agents” Mr. Brain mentioned are.
Smoothing Agents = Windex
had to do this for my summative in grade 12 chemistry
too bad the teacher didnt know the copper would rub right off the nail when we were supposed to rinse the newly played nail under water. what an idiot
i would like to know what is windex and were will i get it from it must have more than windex to its name
come on peter tell us more is it a powder or what?
Windex is a glass cleaner, has lots of ammonia. I don’t know if that works as a smoothing agent, though.
How do you use the windex, is it mixed with the copper sulfate or applied after plating?
can we use this type of electroplating to electroplate transistors made from silicon for example.
i tried this when i was a teenager & won first place in school as science champ.
sir,what chemical can i use to increase brigtness to the cyanide copper plating bath?