Turning Copper into Silver into Gold

No kidding! You’ll be able to show your friends this super-cool magic show chemistry trick with very little fuss (once you get the hang of it). This experiment is for advanced students. Before we start, here are a few notes about the setup to keep you safe and your nasal passages intact:

The chemicals required for this experiment are toxic! This is not an experiment to do with little kids or pets around, and you want to do the entire experiment outside or next to an open window for good ventilation, as the fumes from the sodium hydroxide/zinc solution should not be inhaled.


This experiment is not dangerous when you follow the steps I’ve outlined carefully. I’ll take you step by step and show you how to handle the chemicals, mix them properly, and dispose of the waste when you’re done.


Goggles and gloves are a MUST for this experiment, as the sodium hydroxide (in both liquid and solid form) is caustic and corrosive and will burn your skin on contact.


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Comments

41 Responses to “Turning Copper into Silver into Gold”
  1. Aurora says:

    Yes, just wash it off first with lots of water and wipe it clean to be sure it’s got the sodium hydroxide removed from the surface.

  2. Aurora says:

    You’ll need to use plain Zinc. You can get it here:

    https://www.homesciencetools.com/product/zinc-powder-15-g/

  3. Candyce Ovadal says:

    Will liquid Sodium Hydroxide work?

  4. Candyce Ovadal says:

    Can kids play with the coins after they are turned to gold?

  5. Candyce Ovadal says:

    Will Zinc Nitrate work instead of Zinc Powder?

  6. Aurora says:

    The old C3000 kids did include it, but I think the manufacturers (Thames and Kosmos) no longer have it included, so you can find zinc here: http://www.hometrainingtools.com/zinc-powder-15-g It’s pretty inexpensive. Before you order, go through your chemistry list and see if there’s anything else you’d like to order from that website to save on shipping. 🙂

    And the sodium hydroxide you will make from other chemicals included your kit, because it’s so expensive to ship due to corrosive hazards.

  7. Angela Silva says:

    Should we have received zinc powder and sodium hydroxide in our diamond mastery kit? We can’t find either one.

  8. Aurora says:

    There’s two places for volume control – one is on your computer itself, the other is on the player (see the speaker in the lower right side?) Make sure both are turned on (not muted) and up! 🙂

  9. Aurora says:

    If you mean zinc from a vitamin bottle, it’s not quite the same thing and will not work. You need pure zinc powder, like this one.

  10. Gabriele Pealer says:

    Can I use Zinc tablets instead of Zinc dust?

  11. Leah Thompson says:

    I can get this video to play but it doesn’t have any sound.

  12. Aurora says:

    No, because you’ve fused the two surfaces together with the propane torch. It’s a one-way process. 🙂

  13. Linda Beckwith says:

    Can I turn the penny back to copper and can I do this with other coins?

  14. Rosalind Hitchcock says:

    Similar to some previous comments, our zinc didn’t appear to dissolve, and the penny didn’t galvanize when we followed instructions and let it sit. However, we found that re-heating and stirring the solution, with the penny sitting in it, did the trick.

  15. Aurora says:

    I’ll have my team contact you right away!

  16. Kimberly Miljatovic says:

    how do we upgrade so we can get access to this?

  17. Colleen Canary says:

    Success! Thank you Aurora, we tried again this weekend and with your tips, it worked out great!

  18. Aurora says:

    Yes that’s exactly how you do it. Sorry I forgot to mention that before.

  19. Colleen Canary says:

    🙂 That’s where we bought our zinc from! Would something like a mortar/pestle be good to turn it to powder?

  20. Aurora says:

    I think so. You’ll want to grind it to a powder, but here’s the catch – do not use your kitchenware. You’ll need to use something that is dedicated to science experiments, or you can buy a small bottle of it for pretty cheap from this source (already a powder). And you can boil the solution as long as you take extra care that it doesn’t splash (use a tall enough beaker).

    And kudos to you for encouraging your kids and showing them how to solve problems like this when they come up… just like they’ll encounter in the real world! 🙂 Keep me posted on how it goes!

  21. Colleen Canary says:

    Thanks for getting back to us! This is a great learning opportunity for my little perfectionist 🙂 So, to answer your questions.

    The container states that it is plain zinc powder, yet it looks more granulated like sugar. We started off with distilled water at room temperature, heating it slowly over the alcohol burner, it was hot but did not boil. Is the granulated zinc likely the culprit? would crunching it up a little help?

  22. Aurora says:

    Is your zinc really a powder like flour, or is it granular like white granulated sugar?

  23. Aurora says:

    Let’s try a few things first: did you heat the solution or do it cold? The zinc will not completely dissolved (as shown in the video as bits on the bottom), and it takes a couple of minutes for it to be coated completely. Another question: is your zinc powder plain zinc, or is there something else with it?

  24. Colleen Canary says:

    The only thing I can see that’s different is that our water never turned grey. It seems like the zinc powder didn’t dissolve. We added more water after reading that someone else had a similar issue. But nothing changed.

  25. Colleen Canary says:

    Hmmm, it’s been about 10 minutes and our pennies are still pretty copper colored. They where cleaned with vinegar and salt. Not much is happening, The zinc powder did not completely dissolve, the Sodium Hydroxide pellets dissolved easily, we’re not sure what went wrong.

  26. Colleen Canary says:

    Great! Thank you

  27. Aurora says:

    Yes – they are both made out of the same material.

  28. Colleen Canary says:

    We are hoping to do this experiment soon but I do not have a glass beaker. Could you please tell me, would a Pyrex measuring cup suffice? Thanks!

  29. Dr Tom Frey says:

    You DO get a redox initially. Zn + 2OH- –> ZnO2– + H2. The ZnO2– is the zincate ion. Any you do get H2 but apparently cant see them due to the size or due to the heating process. When pure Zn is oxidized, the 2 electrons migrate to the Cu surface and reduce the zincate ion back to zinc and plate the coin. In essence you are creating the Volta’s original battery one container so you don’t have an outside circuit. Very interesting. I can see why you do this!

  30. Aurora says:

    Sounds like you have a saturated solution, which still works in this experiment (not always the case in chemistry!). You can add more water to help dissolve it and then heat it back up, but you won’t need any more zinc.

  31. Nora Taylor says:

    We cannot get the zinc powder to dissolve in the water and sodium hydroxide. It just settles to the bottom of the beaker. What am I doing wrong? Thanks.

  32. Aurora says:

    Yes, you bring up an excellent point. I use disposable gloves just for this very reason – some of the chemicals will not come off with soap and water – or even with abrasive cleaners (which is not a good idea, as it introduces other chemicals tot he ones you are trying to remove). Sodium hydroxide is caustic and should be disposed of carefully.

  33. april sembrat says:

    I did this experiment with four kids yesterday (not high schoolers, so much supervision) and it was great. At first, I was skeptical and wondering if the pennies where really going to turn silver. Wow! They really did. The kids had a blast heating up the pennies with a blow torch and watching them turn to gold.

    Beware of the chemicals. The kids all wore gloves but when I washed our gloves, I got some of the chemicals on my hands and face. I found rubbing baking soda on was a relief but it is uncomfortable, so be careful 🙂

    Great experiment.

    April
    Santa Cruz, Ca

  34. Aurora says:

    The reaction of sodium hydroxide and zinc to produce hydrogen is a very exothermic one (a lot of heat is produced). With most of the water removed when the residual zinc and hydroxide was wiped out, the heat produced was thus sufficient to ignite paper.

    In the future, the mix should be washed well with water to remove the hydroxide before disposing of the metal. Sodium hydroxide will not harm the plumbing in the sink as it is also used as a drain cleaner (dissolves hair, etc.) but don’t get it on your hands! Vinegar will neutralize any residual sodium hydroxide.

  35. Janet McGrath says:

    We really enjoyed doing the experiment turning copper into silver into gold.
    It turned out we had a problem in disposing of our chemicals and wonder what happened.
    We flushed down the cooled combined chemical of sodium hydroxide and zinc but there was still remaining zinc in the beaker when all the liquid was poured out. So I wiped the remaining zinc out with a paper towel and disposed of it in the trash. About 5 minutes maybe less I noticed a smell and thinking it was from the experiment decided to go and open up some windows (we live in Alaska) for a quick airing out, but was side tracked to throw away some garbage (our garbage in the kitchen is in a retactable bin inside a cupboard) when I pulled out the bin there was a fire!
    I immediately pulled out the trash bag and threw it in the sink to put the fire out with water. In doing so the flames leapt to the floor and counter. My son and I managed to put it out with no damage. Just wide-eyed about a chemical reaction. Talk about buring the house down!!! We won’t forget about this one.
    please advise with what happened. thanks Janet

  36. Aurora says:

    This video is for families with the full K-12 access enrollment. If you signed up only for K-8, then you won’t be able to access the more advanced projects like this one. You can tell which are in the K-12 category when you see “This experiment is for grades 9-12” at the top. Projects that involve fire, dangerous chemicals, power tools, soldering, or require a higher skill level are reserved for K-12. You can upgrade your account anytime by clicking on your Member link from the home page. I apologize if this was confusing!

  37. Elaine Deppe says:

    For some reason I can’t get the video to start. The access was denied.

  38. Debra Thomson says:

    Thank You!

  39. Aurora says:

    Hmm… looks like something was corrupted when we uploaded this file. This sometimes happens when we upload large batches of videos at one time. I’ll get our video team to re-upload the video in the morning. Sorry about that – but thanks for your eagle eye!

  40. Debra Thomson says:

    I can’t get the sound on this video-is this just my speakers/headphones?

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