- a piece of white paper
- an artist's paint brush
- baking soda
- grape juice
- Put two spoons full of baking soda into a cup. Add a cup of water. Stir.
- Use the paint brush to paint a message on the paper, using the baking soda-water mixture as the paint. Let the paper dry completely.
- When you want to reveal the message, brush over the entire paper with grape juice.
Which kinds of juice reveal the hidden message?