Invisible lemon ink

STREAM Activity: Invisible Lemon Ink

Activity best for children ages 4 and up

Invisible ink isn’t just for spies—you can write your own secret message right in your kitchen! Check out this cool way to learn about chemical reactions, using ingredients from your own home. Why does this work? Lemon juice is an acid and weakens the paper. The salt and crayons are a base. When these two chemicals mix together they react and the base helps you see the acidic message!

GUIDING QUESTIONS

  • What do you think will happen when you mix these materials together?

  • Why do you think you can see the message?

  • How could you use this experiment to help you in the future?

MATERIALS

  • White paper

  • Cotton swab

  • Half of a lemon (juice squeezed into a bowl or dish)

  • Salt

  • Crayon

DIRECTIONS

STEP 1

Think of a message you want to write to a family member.

STEP 2

Dip your cotton swab in the lemon juice and write your message on the paper.

STEP 3

Sprinkle salt all over your drying lemon “ink.”

STEP 4

Once the message is dry, use a crayon to color over the paper and reveal your secret message!