Mystery Powders Analysis

My name is Amber and you asked my class
and I to find out what the mystery powder
was. So we experimented mixing different
powders and liquids. After we performed
tests with the liquids and powders we
looked at their reactions. We decided that
the mystery powder was salt, cornstarch,
and baking soda.
We took notes on all of the
experiments and used them to help figure
out what was in the mystery powder. We
had to feel, look, and smell the powders
mixed with liquids to come up with some
One of the tests we did was to add
iodine to the mystery powder. It turned
black and that told us that there was
cornstarch in it. I know that because when
you add iodine to cornstarch it turns black.
The next test that we did was to
compare sugar and salt. We did this to find
out if we could see it in the mystery
powder using a magnifying glass. Before
we did this part of the test, we felt the
powders. We discovered that one powder
was sugar and one powder was salt. The
sugar felt hard and when we added liquid
to it, it dissolved. The salt looked different
under the magnifying glass. It looked like
little squares and it felt hard and sunk to
the bottom of the cup when we added
liquid to it. We knew there was salt in the
mystery powder by its shape and because
we could see the salt sink to the bottom
when we added water to the mystery
We knew there was baking soda in the
mystery powder because when we mixed it
with vinegar, it bubbled, and when you put
vinegar with baking soda, it bubbles a lot.
Mystery Powders
Identification - Identifying chemical or physical
1 Granulated sugar
White crystals
Turns yellow with iodine
Dissolves in water & vinegar
2 Table salt
White crystals
No reaction with vinegar or iodine
Dissolves in water
3 Baking soda
Fine white powder
Turns yellow/orange with iodine
Fizzes with vinegar and water
4 Corn starch
Fine yellowish-white powder
Gets thick, then hard with vinegar
Turns red, ends black with iodine
Makes water cloudy but stays on bottom
5 Plaster
Grainy grayish-white powder
Hardens like a rock in water
Turns yellow in iodine
Melts and hardens in vinegar