You are here

Activity

Invisible ink

Summary: 
Wrote a note in invisible ink
Science content (2016 curriculum): 
Chemistry: States of Matter, Properties of Materials (K-7)
Chemistry: Chemical Changes (2, 7)
Lessons activity is in: 
Materials: 
  • saturated baking soda solution in a tub
  • Q-tips
  • card to write note on
  • grape juice in a tub
  • paintbrush
Procedure: 

Write your note in baking soda solution.
Allow to dry.
The note will be barely visible (though not invisible).

Paint grape juice over the note to make it visible.
(The grape juice turns a different colour when covering the basic baking soda solution).

Notes: 

Other ideas for invisible ink:
lemon juice invisible until heated
Ex-Lax tablets in water (contain phenopthalein) to write. Add baking soda solution to visualize.

Grades taught: 
Gr K
Gr 3
Gr 4
Teacher: 
Ingrid
Teaching site: 
After School Program at Elementary schools in New York City
Activity originally developed and delivered: 

The School at Columbia