This Week's Experiment - #257 Light Soda
This week's experiment is one that has been in my file for quite some time.
I dug it out in response to a question sent to me by Jaclyn in Pittsburgh.
She is a math teacher and had heard about the experiment a while back and was
trying to remember the details. To see why she found this interesting, you
will need:
a large bowl or other container for water
water
a can of regular soda
a can of diet soda
Be sure that both of the cans of soda are the same brand. Since this is a
scientific investigation, we want to control the variables. What is a
variable? It is something that changes. For example, if you were comparing
a can of regular Coke with a can of diet lemonade, you would have several
variables. Besides the fact that one has sugar and the other has artificial
sweeteners, one is carbonated, while the other is not. Also, there is a big
difference between the recipe for Coke and the recipe for lemonade. If you
found a difference in the properties of the two drinks, you might not know
whether the difference was due to the sweetener, the carbonation, or the
recipe. Controlling the variables is very important in science.
Fill the bowl about 3/4 full of water. DON'T OPEN THE CANS. Place the can
of regular soda into the water and watch what happens. Then put the can of
diet soda into the water. Do you notice a difference?
The regular soda sinks, while the diet soda floats. What is the difference?
Both cans are the same size, but one floats and one sinks. The contents of
the regular soda must be heavier than the contents off the diet soda.
The variable that we are looking at is the sugar and artificial sweetener.
Is sugar that much heavier than aspartame, which is the most commonly used
diet sweetener? No, there is not enough difference between the two to cause
one can to sink and the other to float. The clue to the difference can be
found by looking at the sweetness of the two chemicals. Aspartame is more
than one hundred times sweeter than sugar. That means that if you want the
two cans of soda to have the same sweetness, you must put one hundred times
as much sugar in the regular soda. Adding that much more sweetener makes the
difference between floating and sinking.
To get an idea of how more sugar is used, look at the ingredient list on each
can. The ingredients are listed in order by amount, with the most abundant
ingredient first. Sucrose and high fructose corn syrup are both sugars.
Even dividing the sugar into these two groups, you will still see both near
the top of the list for any regular soda. Compare that with where aspartame
is listed on the diet drink. If you are using a cola, you will notice that
the sugar comes before the caramel coloring and that the aspartame comes
after it. It varies from brand to brand, but some use more than 400 times as
much sugar.
From Robert Krampf's Science Education Company
PO Box 60982
Jacksonville, FL 32236-0982
904-388-6381
krampf@aol.com
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