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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Is it REAL gold?
No. But it’s very close in color, as is the ‘silver’. The basic idea behind the experiment is this: by cleaning the pennies in the first step, you clear off any oxide layers to expose the copper surface. When you dip it in the solution, a galvanization reaction starts (just like ‘galvanized nails’) covering the penny with a metallic silver zinc coating.
The torching process fuses the zinc and the copper together to make the gold colored brass coating. Be careful, though, as brass has a low melting temperature and if you leave it in the flame too long, you’ll burn off the brass coating.
Materials:
- propane torch with adult help
- shiny copper pennies
- distilled white vinegar
- Pyrex glass beaker
- sodium hydroxide (solid)
- zinc powder (dust)
- alcohol burner
- stand that fits over the alcohol burner
- lighter with adult help
- wire mesh screen
- popsicle sticks
- water
- salt
- disposable cup
- gloves
- goggles
- tweezers or pliers
Download Student Worksheet & Exercises
The chemical reaction plates the copper on the penny with zinc (called galvanization). The zinc reacts with the hot sodium hydroxide solution to form soluble sodium zincate (Na2ZnO2), which is converted to metallic zinc when it hits the surface of the penny.
Heating the penny fuses the zinc and copper together to form an alloy called brass. The amounts of copper and zinc in brass can vary a lot, from 60-82% copper and 18-40% zinc.
DISPOSAL INSTRUCTIONS: If you simply wipe out the beaker with a paper towel and toss it in the trash, you run the risk of igniting your trash can because the combination of sodium hydroxide and zinc is very exothermic (lots of heat is generated).
Make sure to use plenty of water to remove the sodium hydroxide first before removing 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.
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we are visiting my grandmother”s house right now and it doesn’t have as good a wifi connection as our house does-maybe that’s it?
thanks Aurora
I think this is a problem with your computer or internet connection. Try restarting your computer and ensure you have a good internet connection.
No, you should not use a regular glass jar. It is important to use Pyrex because it can handle higher temperatures and rapid changes in temperature much better than regular glass.
aurora my video does not work. When I do this:
1.Click PLAY.
2.Click PAUSE and let it load completely.
3.Click PLAY again.
it only loads when I click PLAY. When I click PAUSE it does not load. HELP.
why do you need a pyrex beaker? can you use a plain glass jar?
This particular experiment will only work with copper pennies.
Will the same galvanizing process work for metals other than copper
Yes indeed, the zinc should be dissolved. Be sure to apply continual heat as you are stirring the solution. But you should remove the heat source once the solution is near boiling. The experiment does work best when the solution remains warm, so it would be best not to conduct the experiment when it is cold and breezy. If you do the experiment inside, you need to do it near an open window so there is lots of ventilation.
Hello! We did this experiment today and it sort of worked. The pennies were shiny and we followed the procedure. However, the pennies took on only a little of the zinc…so it wasn’t as “wow” as your video. Is the zinc supposed to dissolve? Ours did not. The only thing I can think of was that it was a bit breezy and cooled down our solution after only 4 min. In cooler weather, should we keep the Pennies/solution on the burner? Can this experiment be done indoors? Any suggestions?
Look in the shopping list for this unit for direct links. You can find them in your C3000 Kit or by purchasing individually through companies like Home Training Tools.
Hi, where do I get sodium hydroxide and zinc powder?
A propane grill won’t do the job. That is way to large of a heat source and we need the heat source to be more concentrated.
Hi, my son really wants to do this experiment. I don’t have a propane torch or gas stove. I do have a propane grill. Would that work?
Thank you, Lori
No, it’s brass, which is gold colored. We fuse two metals together to make the appearance of gold (for a fraction of the cost!) It’s a chemistry experiment.
So, was this turned into actual gold?
Do you know the reason it was recommended to add them in this order?
In this case, the sodium hydroxide is solid. Adding it to the water could splash, which you don’t want. Also, in this instance we are adding it to zinc powder and sodium hydroxide, not just sodium hydroxide by alone.
I make soap and have always been taught to never put water into sodium hydroxide, rather sodium hydroxide should be put into the water. Why do you say to put the water into the sodium hydroxide?