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I discovered that violet juice ( of the variety that grow in the yard in
spring) make an excellent pH indicator.

Sue Ann Heatherly
Green Bank Science Center
NRAO- Green Bank, WV

> ISEN-ASTC-L is a service of the Association of Science-Technology Centers
> Incorporated, a worldwide network of science museums and related
> institutions.
> *****************************************************************************
>
>
> For Halloween, use the mixture to paint a pumpkin on a sheet of paper.
> Have
> a plastic knife sitting in a glass of ammonia.   Cover the glass with foil
> and stick the knife through, to control the smell.   Tell the story of
> getting a
> pumpkin from a haunted pumpkin patch.   Then pick up the plasic knife and
> "slice" it across the pumpkin.   The ammonia turns the turmeric blood red,
> and as
> it runs down, it looks like the pumpkin is bleeding.
>
> This Week's Experiment - Making Turmeric Paper
>
> Anyone that has ever taken a chemistry class or played with a chemistry
> set
> is familiar with litmus paper.   These little strips of paper change color
> to
> indicate whether a chemical is acid or alkaline (a base.)   There are
> other
> substances that also change color in the same way.
>
> For this experiment you will need:
>
> the spice Turmeric.   This yellow spice can be found in at your local
> grocery.
> isopropyl alcohol, commonly known as rubbing alcohol.
> a disposable plastic cup
> a disposable paper or plastic plate
> coffee filters
> a variety of items from your kitchen.   Caution: Household cleaners can be
> toxic!   Be careful!!
>
> Pour about half a cup of alcohol into the plastic cup.   Use a disposable
> cup, as the turmeric will stain it yellow.   Put about a teaspoon of
> turmeric
> into the alcohol and stir.   Be careful not to get this on your skin or
> clothes, as it will stain them yellow.   Let it stand for about 5 minutes.
>
> Cut several coffee filters into strips about an inch wide and three inches
> long.   Carefully dip each strip into the turmeric mixture and then place
> them
> on the disposable plate.   Let them dry.   They will be bright yellow.
> It is
> ok if the part that you are holding does not get have the liquid on it.
> The
> liquid is not harmful to your skin, but it will make you yellow for a day
> or
> so.
>
> Once the paper strips are dry, you are ready to test some substances.
> Spray
> a little window cleaner onto one of the strips.   It will turn bright red,
> indication that it is alkaline.   Don't worry if several of the strips get
> sprayed and turn red.   In fact, it would be a good idea to spray several
> of them.
>  Again, let them dry.
>
> Pour a little vinegar into a cup and dip one of the yellow strips into it.
> Nothing happens.   Now dip one of the red strips.   It will turn yellow
> again,
> indicating an acid.   You can test all sorts of foods, to see which ones
> are
> acidic and which ones are alkaline or basic.   The same strip of paper can
> change color back and forth many times.
>
> A dramatic variation of this is to bring a piece of yellow turmeric paper
> near the top of an open bottle of ammonia.   The fumes from ammonia are so
> strong
> that they change the paper red without any liquid touching the paper.
> This
> is a very impressive demonstration.
>
> You can make similar test papers with the juice from red cabbage, blue
> berries, black berries and other fruits.   Some work better than others.
> It would
> make an interesting science project to see which fruit papers gave the
> most
> dramatic changes.
>
>>From Robert Krampf's Science Education Company
> www.krampf.com
>
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More information about the Informal Science Education Network and the
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message  SIGNOFF ISEN-ASTC-L in the BODY of a message to
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