Invisible Ink

Do you have a message you want to send your friend?  Try writing it with invisible ink!

You will need: lemon, saucer, water, teaspoon, Q-tip, white paper, and lamp.

1. Squeeze the lemon juice into the saucer.
2. Add a few drops of water and mix well with a spoon.
3. Dip the Q-tip into the lemon juice mix.  Not too much or you'll make invisible blobs!
4. Use the Q-tip to write a message on ordinary white paper.  Thick paper works best.
5. When it dries the writing will be invisible.
6. Heat the paper by holding it with the written side down near a light bulb.

What Happens:  While it heats up, the invisible ink writing slowly becomes brown and visible.  The words appear on the page.

Why: 

• The juice of lemons has compounds of cardon.
• These compounds have almost no color when you dissolve them in water.
• When you heat them, the carbon compounds break down and turn black.