Secret Ink - Become a spy like Black Widow and send secret messages

"It is always the simple that produces the marvelous. " - Amelia Barr

Become a secret agent and write your own classified invisible messages using just a few materials at home. You can also try this experiment using other ingredients like honey, milk, soapy water, and sugar!

Materials:

• Half a lemon

• Water

• Spoon

• Bowl

• Cotton bud

• White paper

• Lamp or other light bulb or a source of heat

Instructions:

1. Prepare your invisible ink by making diluted lemon juice. Squeeze some lemon juice into a bowl and dilute it by adding a couple drops of water. Mix the mixture with a spoon.

2. To write your message, dip a cotton bud into the lemon juice dilution and write on a white paper. It is best to use an unlined piece of paper so any ink on the paper does not bleed.

3. Wait for the juice to completely dry, so the ink becomes invisible.

4. To read the secret message, place the paper by a source of heat like a lamp or a light bulb, and the ink will become dark.

Science Behind It:

• Acidic fruit juices, like lemon juice, are organic substances that oxidizes when heated, turning brown. By diluting the lemon juice, the ink will become invisible as it dries, and no one will be able to see a message on the paper until it is heated. You can also use different ingredients for the ink, like different acidic fruits (orange and apple juice), honey, milk, onion juice, vinegar, and wine. Messages written with different chemicals like baking soda, ammonia, or salt can also be viewed with chemical reactions, and vitamin B12 dissolved in vinegar, tonic water, and dilute laundry detergent messages can be visible with ultraviolet (UV) light.