Activity Overview
Create secret messages for your friends with this sneaky Science Experiment for all ages to enjoy. In this experiment you will create a watermark which will only be visible when the paper that you are using is wet. You will use two sheets of paper, one wet and one dry, and a ball point pen. Have fun sending secret messages to friends and family members.
The pressure that you exert onto the ball point pen onto the dry paper changes the paper fibers of the wet sheet underneath. This change is only visible when that paper is wet and disappears when the paper is dry.
Materials Needed
- A ballpoint pen
- Water
- 2 sheets of plain paper
How to Do It
- Wet one sheet of paper with water and flatten out on a hard surface.
- Place the dry sheet of paper over the wet one.
- Use a ball point pen to write a secret message on the dry paper by pressing firmly with your ball point pen.
- Carefully remove the paper from the flat surface and separate the delicate wet paper from the dry one. You will see that the message that you wrote is visible on the wet piece of paper.
- Allow the paper to dry and the message disappears from view.
- Wet the paper again to reveal the message.
