In this activity, students will write secret messages that can only be revealed if you know how to read invisible ink!

Materials Needed

Per Student:

Half a lemon (or 1 Tbsp of bottled lemon juice)
1 cup
1 cotton swab
At least 1 sheet of white paper

Enough to Share:

Heated hair dryers

Steps:

Squeeze the lemon juice into a cup, or just pour the bottled juice in.
Add a little bit of water and stir it.
Dip the cotton swab into the mixture and then write a message on a white piece of paper.
Let the paper dry- your message should be invisible.
When you are ready to reveal your message, heat it up by using a hair dryer.

Explanation:

Lemon juice is very acidic. When you write on the paper with it, it eats away at the paper and makes it weak. When you heat it with the hair dryer, the lemon juice burns before the rest of the paper does. This makes it turn brown!

Try it!

Try it with milk or orange juice instead of lemon juice.

Real World:

There are lots of different uses for acidic liquids. One of the most common uses is for household cleaning. The acidity is really good at eating away at grime and gross stuff.