International Day of Women and Girls in Science

Today is the International Day of Women and Girls in Science. This day is very special, as it is a call to action for the world recognize gender inequality in science, and to “achieve full and equal access to and participation in science for women and girls.” We would like to invite all girls to a fun science activity from Peel Respite Service’s Virtual Respite Booklet: Invisible Ink!

Let’s write a top secret message with invisible ink! After you complete it, we welcome you to post a picture of your invisible ink, tagging us with the hashtags #CDRCP and #womeninscience.


  • a halved lemon
  • small bowl
  • water
  • a spoon
  • a small paintbrush
  • white paper


Squeeze any juice into your small bowl and pick out any seeds. Add a few drops of water to the lemon juice and stir. Use the ink you have just created and the small paintbrush to write an invisible message to someone. Once the ink is dry, give your invisible letter to someone and hold it up to a heat source like a lamp. Watch as the ink becomes visible!

The science behind invisible ink: 

The lemon juice contains the chemical element of carbon. When you add heat, the chemicals in the lemon breaks down and releases carbon. When the carbon meets the air, it oxidizes and turns black or brown. This activity helps us learn about the endless scientific possibilities of the objects we use in our day-to-day lives.