This week's experiment is in
honor of all of the mothers on the list. It is a simple chemistry
experiment that you can use to clean the silver. I do ask you to get
permission before doing this. While it may seem a nice surprise, some
silver is not to be cleaned, so be sure to ask before you do
this experiment.
You will need:
some aluminum foil baking soda boiling water some tarnished silver
What causes silver to tarnish? It
starts all bright and shiny and soon turns dark and dull. The tarnish
is a chemical change which takes place when sulfur compounds
in the air combine with the silver to make silver sulfide. Silver
sulfide is black.
Some silver polishes actually
grind away the silver sulfide. This makes the silver nice and shiny, but it
also removes a bit of the silver. This is especially
serious for silver plated items, as years of polishing will wear away the
silver, revealing the metal underneath.
With this experiment, we will
change the silver sulfide back into silver, leaving in place instead
of removing it. To do that, we need to remove the sulfur. By
knowing a bit about electricity and chemicals, we can do this easily.
Line a large pot or your sink
with aluminum foil. Sprinkle about a cup of baking soda over the foil.
Pour in a couple of quarts of boiling water. Add the silver,
being careful not to burn your fingers. The silver should be in contact
with the foil. Within minutes, you should see the tarnish begin
to vanish. At the same time, the foil will darken.
What is happening? The sulfur
from the silver sulfide (Its formula is Ag2S) is moving to join with the
aluminum to form aluminum sulfide (Al2S3). The sulfur is
being moved by electricity. Two different metals in a conducting
solution (water and baking soda) can produce an electric current.
As the current flows, it removes the sulfur from the silver and bonds
it to the aluminum. If you have an electric volt meter, you
can connect one lead to the handle of a silver fork and the other to
the edge of the foil. When the fork is brought into contact
with the foil, the volt meter should show about half a volt. Not a lot
of electricity, but enough to carry the sulfur and clean the
silver.
Back
to Krampf Index Including permission to post
these
experiments on my web site.
