Dr. Kiky Sanford: Hi I am Dr. Kiky Sanford and today on Food Science we are going to have fun with shining silver. Getting tarnished silver clean can be a real hassle with all the creams and the polishes and the hours spend rubbing the silver, going up one of my choice was polishing the tarnished silver in the house. My parents always had parties and I always have to clean the sliver and some how it always seemed like it was dirty making it one of my least favorite chores.
However, now I know that there is a much easier way to get that tarnished silver sparkling clean, it's called the electrolytic cleaning plate. This little plate doesn't look like much, just a thin sheet of metal with some holes drilled in it but what it can do is actually really surprising, first you take the metal plate and you put in some kind of a wash basin then cover the plate with water up to a level that will actually cover the silver objects that you are trying to get clean and make sure this is nice and full of hot water, make it as warmer as hot as you possibly can and then we are going to take washing soda, sprinkle it over the plate, and then let it dissolve in a little bit. You are going to take your silver and make sure it is contacting the aluminum plate, give it a second to start acting and you should see it just start going there are bubbles that will start to arising, you will actually see some kind of a sulfur gas arising from the surface of the water.
Make smell of a little bit like rotten eggs, around about 30 seconds your silver should be pretty much clean, you can take it out of your hot water give it a little rinse, and then wipe it off. The tarnish on this fork is actually called silver sulfide. It comes from the silver in the fork reacting with sulfur in the atmosphere. You can try rubbing it off with polishes but you are actually going to loose some of your fork. In the reaction involving the aluminum plate the silver sulfide is chemically converted back into silver.
So you don't actually loose any silver. Many metals in addition to silver will form compounds with sulphur. But some of them like aluminum actually have a greater affinity for the sulphur. In this experiment the sulphur atoms are being transferred from the silver to the aluminum, freeing up the silver and forming aluminium sulphide. The temperature of the water helps to speed up the reaction so the warmer the water the faster the reaction goes. The washing soda which is also known as sodium carbonate acts to create an electrolytic current that builds the salt bridge that carries the electrons of the sulphur from the silver to the aluminum.
Since I know how this plate works, I wonder if I can replace it with something from around my house, like aluminum foil -- it works. But remember it's not just food, it's science.
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