Several containers of clear liquid are displayed. A dye is placed in one of the containers and it changes to a golden yellow. Another clear liquid is added and it turns to a deep blue/black. A third clear liquid changes it to a wine red, and the fourth one restores it to sparkling clear again.

You will need the following chemicals:

1. Rubbing Alcohol
2. Tincture of Iodine
3. Ex-Lax(R) Tablets (the pills, not the chocolate stuff)
4. Corn Starch
5. Washing soda with ammonia
6. White Vinegar
7. Hypo (sodium thiosulphate) from a photography supply store

• Dissolve one Ex-Lax tablet in 2 oz. of rubbing alcohol to make a phenolphthalein solution.
  (note: Since the original writing, Ex-Lax has changed their formula. You will probably need to get phenolphthalein solution from a chemical supply house or a chemistry teacher.)
• Heat 8 oz. of water to boiling and dissolve 1 tsp cornstarch in it.
• Dissolve 3 tsp. washing soda in 8 oz. of water.
• Dissolve 1 tsp. hypo in 8 oz. water.
  All measurements are approximate. Experiment with different quantities for the effect you want.

  The first solution should be plain water. Adding a few drops of iodine will turn it golden yellow.

  The next solution should be the washing soda with a little starch water mixed in. The starch reacts with the iodine to make a blue/black color. If you use the starch and iodine sparingly you get a nice navy blue for U.S. patriotic themes. Larger concentrations look nearly black. Experiment to get just the effect you want.

  The next solution should be hypo with a little Ex-Lax solution mixed in. The hypo combines with the iodine to cancel out the starch reaction and make the solution clear. The phenolphthalein in the Ex-Lax turns red in the presence of a base (ammonia) giving the next color change. The final solution is the white vinegar, which neutralizes the ammonia and makes everything clear again.

  (Note: By alternately adding washing soda and vinegar to the solution you can change back and forth between red and clear.)

  Presentation

  A color changing liquid is only a chemical curiosity unless there is a story to support it. I sometimes use a patriotic theme with Blue representing Truth, Red for Courage and White for Purity. You may want to mix this with a flag production for a finale. You could also skip the iodine and hypo and do a water-to-wine-to-water effect. The main thing is to have an entertaining story and use the color changes to highlight the events.

  Application

  These colors work beautifully with the "wordless book" Gospel presentation. Gold represents heaven with its golden streets, and sunlight reminding us that God is light, and He wants us to live with Him in heaven. The next solution can be labeled "Sin", and when it comes into our lives it puts us into spiritual darkness, separating us from God and His plan. Label the next solution "Jesus" who shed his blood to cleanse us from sin, and the last solution "Faith" by which we receive His cleansing and forgiveness.

  The Easy Way

  Rev. Douglas E. Stoll has put together a similar effect that you can purchase very reasonably. It only has one color change, but all of the materials are included with enough chemicals for about 20 presentations. Refills are available. Visit his web site for a demonstration and ordering information.

  UPDATE A reader recently asked the following: Could you help me understand some of the items needed and where I can get them. Can you give me some "lessons for dummies"? Where would I go for each of them and what would I ask for. If there is another name for these (brand name, generic name,…) that would be possible. Also, I had thought about using red food coloring in water and then Oxi-Clean to take the color out. Have you tried this? What are the pro's and con's of this? Here's my reply: Tincture of Iodine is available at any drug store. It's the same Iodine that is used to disinfect minor cuts."Tincture" just means "dissolved in alcohol" Washing soda is a laundry cleaning enhancer. Any moderately strong alkali will do. Plain washing soda might be strong enough. Plain ammonia will work, but it has a strong odor and is harmful to inhale. It just needs to be strong enough to effect the color change in the phenolphthalein. You may need to get sodium thiosulphate and phenolphthalein solution from a chemistry teacher or a science hobby shop. A photography hobby shop may have hypo if you ask. It is also called "fixer" in photography. The ex-lax formula has changed since I wroth the article and the new formula won't work. If you get phenolphthalein solution you won't need the rubbing alcohol. I have not tried food coloring and Oxi-clean. It may work, but you would lose the part where the red color appears unexpectedly. Here's a quick run-down on what is happening chemically: Iodine in water will show up as a light to medium yellow depending on the concentration. It reacts with starch to make a blue-black color, again depending on the concentration. Hypo reacts with iodine to make a clear solution. This pulls the iodine away from the starch molecules and removes the blue/black color. Phenolphthalein is clear in a neutral or acid solution but turns red when the pH level (alkalinity) rises. Adding an acid(vinegar) reduces the alkalinity and returns the solution to clear. I chose the chemicals listed because they are relatively safe and were commonly available at the time.

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