EXPERIMENTS ARE FUN!

   SECRET MESSAGE

To start with, we are going to need the juice of half a lemon, some cotton, adhesive tape, a match or a stove or some kind of fire, a toothpick and a paper.

First of all, we going to make a little cotton ball and join the cotton and the toothpick with a piece of tape:

This is the result of the brush that we're going to use:

Squeeze the half lemon to get the juice:

Then dunk the brush in the lemon juice:

And start writing your secret message. At first you'll be able to see it because it will be wet, but then it's going to dry up.

Once the paper has dried up it will look like this:

Finally, when you want to see the text you have to get the paper close to a stove or another heating source and the text will start to appear:

This is our secret message!