Pink Lover - How to Do Color-Changing Magic

This Pink Lover experiment is like magic (actually, this is what magicians usually do). You can make the colorless liquid into pink by just pouring the liquid into another empty cup and make it turn back colorless by just a blow of air.

Age：5+          Time: < 20 mins

 Safety 

1. Adult supervision.
2. Do not drink the liquid.

 Materials List 

• Water
• Wine glass
• Drinking straw
• Dropper
• Medicine spoon
• Phenolphthalein
• Sodium carbonate
• Disposable cup

 Instruction 

Step 1/5 – Dissolve about 3g Sodium Carbonate in about 50ml water.

Step 2/5 – Wet the wine glass with the sodium carbonate solution.

Step 3/5 – Dissolve several drops of Phenolphthalein into about 50ml water.

Step 4/5 – Pour the Phenolphthalein solution into the wine glass. You can find that the colorless solution change into red.

Step 5/5 – Blow the air through drinking straw into the liquid. You can find that after a while the red color change back into colorless.

 Troubleshooting 

Why I do not have the pink color?

— Make sure you have wet the wine glass with the sodium carbonate solution completely.

Why did my pink color fail to change back to colorless?

— Make sure you blow the air into the pink liquid and continue blowing for a while, more than 10 seconds.

 Scientific Description 

Phenolphthalein is a chemical compound, usually used as a PH indicator. For this application, it turns colorless in acidic solutions and pink in basic solutions. Sodium carbonate is the inorganic compound, also known as washing soda, soda ash, and soda crystals. It gives moderately alkaline solutions. So, the sodium carbonate can make the Phenolphthalein solution into pink. The air we blow out contains lots of carbon dioxide which combined with water will give Acidic solutions. The Acidic solution given by carbon dioxide neutralizes the alkaline solution given by sodium carbonate. Thus, when we blow the air into the pink liquid for a while, the pink color burns back into colorless.

 Extensions 

You can try to pour some vinegar into the pink liquid and see what will happen.

 Disposal 

Pour the solution into the drainage and wash down with plenty of water.