From Anne Marie Helmenstine,
This popular chemistry demonstration is often
called turning water into wine or water into
blood. It's really a simple example of a pH
indicator. Phenolphthalein is added to water,
which is then poured into a second glass containing
a base. If the pH of the resulting solution
is right, you can make the water turn from clear
to red to clear again, as long as you like.
Time Required: Minutes
1. Sprinkle sodium carbonate to coat the bottom
of a drinking glass.
2. Fill a second glass halfway full of water.
Add ~10 drops phenolphthalein indicator solution
to the water. The glasses can be prepared in
3. To change water into wine or blood, pour
the water with indicator into the glass that
contains the sodium carbonate. Stir the contents
to mix the sodium carbonate, and the water will
change from clear to red.
4. If you like, you can use a straw to blow
air into the red liquid to change it back to
5. The principle is the same as for the disappearing
ink formula. Phenolphthalein is an acid-base
Phenolphthalein and sodium carbonate can be
ordered freely from any scientific supplier.
Most grade school and high school science labs
have these chemicals, though you can order them
Don't drink the water/wine/blood. It isn't particularly
toxic, but it isn't good for you either. The
liquid can be poured down the drain when the
demonstration is complete.
For a normal drinking glass, the ratio used
to get the reversible color change reaction
is 5 parts sodium carbonate per 10 drops of
a phenolphthalein stock solution.
What You Need:
phenolphthalein pH indicator
straw or pipette