This popular chemistry demonstration is often called turning water into wine or water into Blood. It is really a simple example of pH indicator. Phenolphthalein (an indicator) is added to water, which is then poured into second glass containing a base. If the pH of the solution is right, you can make the water turn from clear to red clear again, as long as you like.
For this you must follow these simple steps:
1. Sprinkle Sodium Carbonate to the bottom of a drinking glass.
2. Fill a second glass halfway full of water. Add about 10 drops of phenolphthalein indicator solution to water. The glasses can be prepared in advance.
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 clear.
5. The principle is same as for disappearing ink formula. Phenolphthalein is an acid base indicator.