If you don’t have equipment lying around for this experiment, wait until you complete Unit 10 (Electricity) and then come back to complete this experiment. It’s definitely worth it!
Electroplating was first figured out by Michael Faraday. The copper dissolves and shoots over to the key and gets stuck as a thin layer onto the metal key. During this process, hydrogen bubbles up and is released as a gas. People use this technique to add material to undersized parts, for place a protective layer of material on objects, to add aesthetic qualities to an object.
Materials:
- one shiny metal key
- 2 alligator clips
- 9V battery clip
- copper sulfate (MSDS)
- one copper strip or shiny copper penny
- one empty pickle jar
- 9V battery
You may have connected the battery backwards. Be sure to connect the key to the black (negative) wire.
Great! I’m glad that switching the wires solved the problem. To use salt and vinegar, use 1/4 teaspoon of salt for each 1/2 cup of vinegar.
Yes the key was on the negative wire. In the download materials it says you can use salt and vinegar – would this work better? What amounts/combination would be best?
Hi we used copper wire and salt water and the reaction started happening and all the copper came off the wire and made the water black but no copper went on the key. What might have happened?
Yes indeed, you can use copper wire, but be sure to remove any plastic insulation before connecting it to the alligator clip. If you don’t have copper sulfate, you can use saltwater (just add salt to warm water and stir until the salt dissolves. So, instead of the copper strip, you can use bare copper wire and instead of copper sulfate, you can use saltwater.
Hi there can we use copper wire instead of a strip of copper? What if we bunch up a few wires together by twisting them and then attach to the alligator clip? Will it work? Can we do the same thing instead of getting copper sulfate where you said in another response use 2 copper pennies (we don’t have copper coins in Australia) can we just put a bunch of copper wire in the solution and connect to a battery?
We finally did this one and it was so cool. Every time I look at my spoon (we tried a spoon after successfully using two keys) I am so amazed that we managed to coat it with copper from an old penny using a 9V battery and some chemicals we ordered off the internet. My dad loved copper and I wish I could show him this.
You really need a 9volt battery for this experiment. D or AA batteries only provide 1.5 volts each.
I thought I had all the supplies for this unit but it turns out I don’t have the 9V battery clip. Can we use a different battery compartment? We have ones that fit a D battery and one that fits 2 AA batteries.
On the experiment sheet for December 2021 it says “do plants sore energy”. Just noticed 🙂
The key receives the copper plating because it is attached to the negative (cathode) side of the battery. The plating occurs due to the direction of current flow.
There is only a limited amount of copper in the copper sulfate solution. Attaching the copper strip to the positive side of the battery allows oxidation to occur, which pulls copper ions off the strip, thus replenishing the copper in the solution.
Why doesn’t the metal of the key plate onto the copper?
Also, since there is copper in the solution, why does the experiment need a copper piece? Is it because the dissolved copper sulfate is not ionized?
We’re going to talk about it today in our class – you can put the copper ions in the solution by placing two copper pieces in a solution and connecting them to a battery and leaving it for about 20 minutes, until it’s a blue-green color.
What can i use instead of copper sulfate?
Thanks for the clarification – I’ll make sure it’s clear which connections are which for you!
Thanks Aurora!
Hi there,
In the student worksheet instructions for this experiment (which was really cool by the way) you told us to connect our batteries in series and then told us to connect them in series again but in a different way which our dad said was actually connecting them in parallel.
You can find copper sulfate here: https://www.homesciencetools.com/copper-ii-cupric-sulfate-30-g
Where do you get this copper sulfate?
No, do not hook up a car battery to this experiment (or any other experiment for that matter). Car batteries have way too much amperage and should not be part of a lower-power experiment like this.
If I use Salt (instead of copper sulfate), will a Car battery be enough power?
Yes – anything metal will work.
Can you do this to coins?
Awww…. 🙂 Thanks so much – so glad you found us.
There’ more than one Apologia section – which one are you looking at? Can you provide a link to the main page?
Is there anyway we can have access to the Apologia Science section? That is the curriculum that we are going through.
So gad I found you! My son has always been a “future mad scientist” and he sure didn’t get it from me! I can’t replace your wisdom or enthusiasm. I have always wished I had a scientist next door. Seems God still answers prayers! 🙂
I’ll ask my question again.
We tried this experiment using Copper (II) Sulfate. We put the key in the solution and it turned black in ten seconds. We wiped it off and it was still the same metal plating. We did this waiting for about 5 minutes and it still was the same metal plating. What did we do wrong?
We tried this experiment using Copper (II) Sulfate. We put the key in the solution and it turned black in ten seconds. We wiped it off and it was still the same metal plating. We did this waiting for about 5 minutes and it still was the same metal plating. What did we do wrong?
Wow – I am sorry the kit has so many changes! We just evaluated it only a few months ago.
Okay, the cupric sulfate should work, as long as it’s still blue. You’ll find they really don’t dissolve (as least, to the naked eye), but the water color should change slightly. The light brown is your coating of copper. Try rubbing the dull coating with ketchup or placing it in a solution of salt-and-vinegar for a minute after you’re done electroplating to shine it up (although this may not work , as cupric sulfate tends to leave a dull instead of shiny coating). There’s another option, though – use a shiny copper piece of pipe (or pipe fitting) for the copper electrode and omit the copper sulfate. It will take longer, but you’ll get a shiny coating.
If you’re curious, here’s more info about the difference between copper sulfate and cupric sulfate, although it’s a bit more involved to understand. I asked one of our chemists here in the lab, and here’s the answer:
Copper is one of those metals that has multiple valence states (i.e. more than one positive charge). Copper can be +1 or +2. Copper +1 is designated cuprous or copper (I). Copper +2 is cupric or copper (II). So you can have 2 copper sulfates. Sulfate has a charge of -2; SO4^-2. The positives must balance the negatives in a compound. With Cu(I), the formula is Cu2SO4 and is called cuprous sulfate or copper (I) sulfate. With Cu(II), the formula is CuSO4 and is cupric sulfate or copper (II) sulfate. If you have the blue crystalline compound, you have CuSO4.5H2O, the pentahydrate. That’s the stuff used in electroplating.
Hi,
Another surprise, I guess..
In the kit, Copper Sulfate appears to have been replaced by Cupric Sulfate. The company Parts List says, “Copper II (cupric) sulfate, 30 g ”
The 30 grams were essentially a number of small rocks. We dropped a number of these rocks into 50 ml of distilled water and crushed (without much success) the rocks as much as possible. After an hour, very little of these rocks had dissolved. We went ahead in the 50 ml water and dropped a shiny penny (utilized a fresh 9v and a shiny small key). Both the key and penny changed to a light brown and no black discoloration. ..Same results after 30-45 minutes. The light brown would not rub off and was not shiny. In fact, the kids considered the key corroded.
🙂 It has been an interesting few days. Good preparation with things not going quite right – as we lead up to the Science Fair and project.