Materials:
- adult helper to cut the lemon
- lemon
- 2 cotton swabs or 2 paint brushes
- paper
- red cabbage water(from previous experiment)
Experiment:
Have an adult cut the lemon in half. This is your ink.
Dip the end of the cotton swab, paint brush or your finger into the “ink” and use it write a secret message or draw a picture onto a piece of paper.
Let the juice dry. The paper will look blank.
Take a clean cotton swab or paintbrush and dip it into some red cabbage water. Paint it over the lemon writing.
Why?
Red cabbage juice is an indicator that is used to test acids and bases. The acid in the lemon juice reacted to the cabbage juice and changed color so you could see your message.