For social studies this year we are studying U.S. History. John was a double major in college and one of those majors was history, so this is a subject we don't have a curriculum we follow. Part of what we are doing this year is watching Liberty's Kids (Click here to find out more about Liberty's Kids). We rented these videos a few years ago from the public library and this year we found them on Netflix. Today's episode was entitled 'Postmaster General Franklin' and we did a little project to go along with it. Invisible Ink!
With simply baking soda and water it is easy to make invisible ink. We used about 2 spoonfuls of each, but then poured off a little of the water. The girls used cotton swabs to draw with the solution on printer paper.
Next let the paper dry.
There are a few different ways to make the invisible ink become visible, a heat source such as a light bulb or candle, grape juice, or lemon juice. The show used a candle as a heat source. I wanted to stick with using a heat source, but a light bulb instead of a candle. I just imagined our whole house going up in flames at the thought of the kids holding paper over a candle. Using a light bulb, you still have to be careful. The paper can still catch on fire. This was the plan, however, all of our light bulbs are the low heat, energy efficient variety. They just don't emit enough heat for this project, so we went with lemon juice. Anara used her fingers to spread the juice on the papers. By the time Nia got back to the table, Cameron had already finished her paper for her.
Here are the results, which were only a little easier to make out in person than by this picture. They must have used a better medium or tools in Franklin's day or the messages would have had to of been really short. These didn't turn out great, but the kids got an idea what it would have been like to use invisible ink. It's a challenge writing something when you can't see what you are writing.