Experiments with lemon: write a secret message


Learn to write a secret message using lemon juice.

Things we need:

  • 1/2 lemon
  • small plastic container
  • a cutting board
  • knife
  • spoon
  • a cotton swab
  • white paper
  • a lamp with the bulb

On the table will cut the lemon in half with a knife. Shall squeeze half a lemon on the plastic container.

We help plastic spoon to remove the seeds. Add a few drops of lemon juice to the water we obtained above and mix well.

Dip the cotton swab into the mixture and write a message on the white paper, and let the lemon juice dry. The role will be dry.

To read the message we need to hold the paper in front of a lamp. Place it near the bulb but without the touch. The heat from the bulb will cause the message.

What happened?

Lemon juice contains compounds of carbon dioxide which is colorless when it is dissolved in water. When heated, they produce carbon, which is black.

So you can read the invisible message.

Notes:  Be careful not to burn the paper when it passes over the bulb and not to cut with the knife. Adults should always supervise children when they are conducting experiments.