This fun demonstration purports to turn red wine
into white wine, milk, raspberry milkshake and fizzy lemonade.
It relies on the audience not noticing
that you've prepared your glasses by adding small volumes of liquid to them before the demonstration.
For this reason the audience being able to see the precise details of the procedure
is less important than it is in some of our other demonstrations.
If you have a post-sixteen audience you may wish to discuss the chemistry of the reactions taking place.
Before the demonstration you'll need to prepare your red wine.
This is an acidified solution of potassium manganate(VII).
You should pour the red wine into an empty wine bottle, carafe, or suitable jug.
Before the demonstration you will also need to make up solutions
of sodium thiosulfate, barium chloride and sodium carbonate.
Out of sight of the audience, and before the demonstration,
you should prepare your five glasses.
The first glass will contain only red wine so that one should be left empty.
The second glass will contain white wine
and you should prepare that by adding 1 centimetre cubed of sodium thiosulfate
to that glass before the demonstration.
The third glass will contain milk
and to that glass you should add 1 centimetre cubed of sodium thiosulfate,
and also 3 centimetres cubed of barium chloride.
Glass 4 will contain our raspberry milkshake
and that glass should be prepared with 3 centimetres cubed of barium chloride only.
And to the final glass, which will contain our fizzy lemonade
you should add 1 centimetre cubed of sodium thiosulfate,
and also 3 centimetres cubed of sodium carbonate.
Now you're ready to do the demonstration.
To each glass in turn, with suitable words about magic drinks,
you should add approximately 125 centimetres cubed of the acidified potassium manganate(VII) solution.
Glass 1 will contain only our red wine.
In glass 2 our white wine is produced
by the reduction of managanate(VII) ions to almost colourless manganese(II) ions.
In our third glass our milk is produced
as the manganate(VII) ions are again reduced to colourless manganese(II) ions
and a white precipitate, a barium sulfate, is produced
from the reaction of the sulfate ions in the acid in the wine,
and the barium ions that were present in the glass already.
Our fourth glass contains raspberry milkshake
and this is produced because of the purple manganate(VII) ions
and the white precipitate of barium sulfate.
And in our final glass our fizzy lemonade is produced because of the reaction of the acid in the wine
with the carbonate ions producing bubbles of carbon dioxide
and again the purple colour of the manganate(VII) ions
has been changed to the colourless manganese(II) ions.
After the demonstration it's well worth removing the glasses from the view of the audience fairly quickly
because the white precipitate of barium sulfate in glasses 3 and 4 will slowly settle out,
and glasses 2 and 5 will slowly become cloudy
because of the production of a sulfur precipitate from the reaction of thiosulfate ions with the acid in the red wine.