Communication is very important, but sometimes, we don’t want just anyone to be able to read the notes we are writing. In addition to learning about chemistry, you and your child will be able to form your own secret club and share top secret messages after learning how to make Invisible Ink!
There are two methods of making Invisible Ink. Here’s what you’ll need to try both methods:
- Cardstock
- Measuring spoons
- Three cups or small bowls
- A spoon
- Q-tips or a paintbrush
- Old newspaper or cardboard
- Paper towels
- Lemon juice
- Water
- An iron
- Baking soda
- Turmeric and rubbing alcohol OR concentrated grape or blueberry juice
For this experiment, we will have to create three separate solutions by mixing different ingredients together in each of our three bowls.
In the first bowl, mix the juice from half a lemon with half a teaspoon of water. In the second bowl, mix one tablespoon of baking soda with one tablespoon of water. In the third bowl, mix ½ tablespoon of turmeric powder with 3 tablespoons of rubbing alcohol.
Now that our solutions are ready, let’s test out our two Invisible Ink methods!
For method one, dip a Q-Tip into the lemon/water solution. Use the wet Q-Tip to write a message on your card stock. Rewet your Q-Tip if you need to, but be careful not to get your paper too wet. Can you see your message on the paper? Now let it dry fully… Can you still see your message now that it’s dry?
Plug in your iron and put it on the high setting. Help your child carefully run the iron over the dry paper several times. What happens when you apply heat to the paper? Can you see your message? Why does this happen? Lemon juice contains citric acid. When you apply citric acid to the paper, it weakens the fibers of the paper, and they start to decompose. Citric acid is also a carbohydrate, and carbohydrates do not like heat. When you apply the heat from the iron, the carbohydrates begin to release carbon, which oxidizes when it comes in contact with the air. The result is a brown substance that makes your secret message visible!
Now let’s try method number two!! Dip your Q-tip in the baking soda solution and write a message on a new piece of cardstock. Again, make sure not to get your paper too wet. Allow the paper to dry completely. If you see any remaining baking soda on the paper, remove it with a paper towel. Next, dip a Q-tip or paintbrush into the turmeric and alcohol solution. Paint the whole paper with the turmeric solution. What happens?
Baking soda is alkaline. It gets absorbed by the paper just like the lemon juice. When the turmeric and alcohol come into contact with the baking soda on the paper, the solution turns from yellow to deep red, revealing your secret message!
Who knew that chemistry could make communication so fun?! Check out the full experiment and more of the science and history behind Invisible Ink from Science Buddies HERE.
As always, get as creative as you want, and above all, have lots of fun learning together!
We’ll see you right back here next Saturday for another STEAM Saturday activity! Scroll through the rest of our website to learn how Critchlow Adkins is Building Brighter Futures for the children and families we serve!
