Science Smarts: Secret science Santa letter

By Patty Rooks on December 10, 2022.

I just looked at the calendar and cannot believe how fast Christmas is approaching. With Christmas just around the corner, I hope that all of the young scientists out there have written their letter to Santa so they will not be missed on Christmas morning!

Just in case you are worried your letter will fall into the wrong hands, I suggest we use a little science to write Santa a “secret” letter with all of your wishes on it. Do not worry, Santa and I have a great relationship and I have shared with him just how to decode this message. Let’s get started.

*Remember to ask an adult before doing this experiment.

Materials

– Kettle

– Water (preferably distilled)

– Measuring cup

– Teaspoon

– Cornstarch

– Stirring spoon

– Iodine (you can purchase iodine at a drugstore – CAUTION it is poisonous)

– Eyedropper

– Cotton swabs

– Writing paper

– Empty bottle (labelled disappearing ink – don’t drink)

Procedure

1. Fill the kettle full of water and bring it to a boil.

2. Measure out one cup of water into the measuring cup.

3. Measure one teaspoon of cornstarch.

4. Add the cornstarch to the cup of water.

5. Stir the cornstarch into the water until it is all dissolved.

6. Set aside.

7. Mix the iodine solution.

8. Measure out one cup of water.

9. Add 7-10 drops of iodine to the mixture.

10. Stir with the spoon after adding each drop.

11. You want to have a nice blue mixture.

12. Pour into a labelled bottle – label it poison, do not drink. (a spray bottle will work well).

13. Pour the disappearing ink into a labelled bottle.

14. Carefully dip the cotton swab into the disappearing ink mixture and write your message on the writing paper. You will have to rewet your cotton swab several times as you write.

15. Allow the message to dry (in a secret location)!

16. Be patient, as it may take a day or so, but the ink will disappear.

17. Get an envelope and address it to Santa. Do not worry; he knows that when he receives it, he will have to fill a spray bottle with an iodine solution in order to get the message to reappear!

What is going on?

When you mixed the cornstarch in the water, you created a basic solution. As the cornstarch solution dries, it will react with the air and eventually it will disappear. When you add iodine to starch, a bluish black solution appears. By adding the iodine to the paper where you wrote the message, the letters you wrote in the cornstarch solution should turn bright black and reappear.

Teachers – if your school is interested in having a science fair club, make sure you call soon so I can pop by and give you some great pointers!

Patty Rooks, Senior Scientific Consultant PRAXIS, “Connecting Science To The Community”. Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: #12 826 11 Street S. E., Medicine Hat, Alberta, T1A 1T7 Phone: 403.527.5365, email: praxis@praxismh.ca.

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