There are two forces at work in tooth decay from
soda. The first of these is, as you mentioned,
the carbonation. Carbonated beverages contain
carbon dioxide, or CO2. Soda like Coca-Cola is
made of water (H20), flavored syrup, and CO2. The
equation for carbonation is as follows:
H20+CO2--->H2CO3. The right side of the equation
is carbonic acid.Tooth decay is caused by acids
dissolving the enamel of the teeth.
might worry that you have been soaking your teeth
in acid every time you take a big gulp of soda,
and you would be partially correct. Since the
carbonic acid that is formed in the soda is
dissolved in the water, it comes into contact with
your teeth for only a short time every sip.The
second contributor to tooth decay is sugar. Sugar
from sodas (and fruit juices, for that matter)
coats the teeth every time you take a sip.Bacteria
in our mouths break down the sugar into acids,
similar to the equation above for carbonic acid.
However, since sugar is sticky, it sticks to your
teeth and therefore provides a longer time of
exposure to acids. That is why sugar is usually
the main culprit in tooth decay.
Now, for your
experiment. Since you want to study only the
effects of carbonation, you must use that as your
only variable (ask your science teacher what this
means if you are not sure). I would suggest using
a drink that contains only carbonation, and no
sugar. You also want it to be clear so that you
can see what is happening as it happens.
Therefore, use 'soda water' or 'seltzer,' which is
just CO2 in water. (You could also vary the
experiment by having lots of different kinds of
soda and checking the effects of *sugar*, but that
is a different experiment.)The fizziness you
experience when you have a freshly opened can of
soda is the carbon dioxide 'escaping.' However,
as the soda sits and gets 'flat,' the carbon
dioxide is turning into carbonic acid.
fill a glass with fresh seltzer, it will dissolve
a tooth. However, unless you have lots of baby
teeth sitting around the house and your parents
are looking for a cool way to get rid of them, I
wouldn't suggest using teeth!Instead, take a piece
of limestone (which also has calcium in it!), and
drop it into the glass. As time wears on, it will
dissolve more and more. If you refill the glass
with fresh soda, it will dissolve slower than if
you just let the same glass sit and turn flat. Why?
Click Here to return to the search form.