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Picture this:  You see two people meet up. Person 1 passes Person 2 a few sheets of paper. They both leave in opposite directions. Another person bumps into Person 2, who drops the sheets on the ground. One sheet lands at your feet and the other sheets are picked up by Person 2, who then leaves in a hurry. You pick the sheet of paper up and notice it is blank… or is it? 

Did you know that there is a way to write without leaving a trace? Invisible Ink!

The invisible ink experiment that we will conduct below is based on something called oxidation. Oxidation is a chemical reaction that involves the loss of electrons. Specifically, the reaction gains oxygen and loses hydrogen (kidzsearch).

When iron is left outside and exposed to the air (which has oxygen in it) or exposed to water (which also has oxygen in it), you get oxidation, or in the case of the iron that is left outside, you get rust (study.com).

The invisible ink experiment that we will conduct below is based on something called oxidation. Oxidation is a chemical reaction that involves the loss of electrons. Specifically, the reaction gains oxygen and loses hydrogen (kidzsearch).

Oxidation also occurs when fruits and vegetables are exposed to air. Ever seen apples go brown? Lots of fruit juices like lemon juice, for instance, go brown when exposed to air or hot air. That is oxidation (scientificamerican).

Supplies:

  • Lemon Juice (You can squeeze a lemon or just use bottled juice)

  • Bowl

  • Q-Tip

  • White Computer Paper

  • Heat Source Like a 100 Watt Light Bulb, Hair Dryer, Iron (not on steam), Oven Burner* *This should be done under adult supervision.

Step 1: Pour/Squeeze lemon juice into a bowl.

Step 2: Dip the q-tip into the bowl.

Step 3: Write your secret message.

Step 4: Allow your paper to dry completely.

Step 5 : Let an adult help you with this step as things can get really hot and burn you.

Gently heat your paper with the heat source (I used an oven burner) to reveal your message. 

Librarian Tip: You may want to try out vinegar or milk as secret message mediums.

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