This Week's Experiment - #334 Instant Fizz
A few weeks ago we saw how yeast is used to make all the tiny holes in bread.
This week we will look at a different way that cooks put the tiny holes in
baked goods. This method uses chemistry instead of biology. To try it, you
will need:
a glass of water
baking powder
baking soda
vinegar
Place the glass of water in the sink or on a plate, so you don't make a mess.
Then sprinkle a small spoonful of baking powder into the water. Watch
what happens. It foams and fizzes. How can it to that?
Have you ever mixed vinegar and baking soda? If not, get a fresh glass and
try it now. Put a little vinegar into the glass and then sprinkle in some
baking soda. What happens? Basically, the same thing that happened with the
baking powder and water. You get foam and fizz.
What you are seeing is an acid (vinegar) reacting with a base (baking soda).
This reaction releases bubbles of carbon dioxide gas. That is what makes
the foam.
But with the baking powder, all you added was water. How does that work?
The baking powder is actually a mixture of two chemicals. It contains baking
soda, but instead of vinegar, it contains one of several acidic powders.
Mine contains calcium acid phosphate. Others can contain other acid salts,
such as sodium aluminum sulfate, sodium aluminum phosphate, or dicalcium
phosphate dihydrate. Any of them provide the acid that is needed to combine with the
baking soda to make the bubbles. As long as both powders are dry, they do
not react. It is only when you add water that things get going.
It is important to keep your baking powder sealed up, as even the moisture in
the air can cause it to react. If it has already reacted, then it will not
produce the bubbles you need to make your baked goods rise. If your baking
soda is old, be sure to test a little in water before using it in cooking.
That way, you will be sure that it will work.
Have a wonder filled week.
From Robert Krampf's Science Education Company
PO Box 60982
Jacksonville, FL 32236-0982
904-388-6381
krampf@aol.com
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