top of page

Invisible Ink

IMG_20200401_132311_edited.jpg

Materials

white paper

white vinegar,  lemon or lime juice

cotton buds

heat source: hair dryer, lamp or toaster

Difficulty: 

Time: depends on drying time

Adult supervision: possibly to help with revealing the message

Dangers: heat

Instructions

  1. Put some lemon juice or white vinegar in a small bowl/container

  2. Use the cotton bud as your pen: dip the tip into the lemon juice or vinegar and write a message on the paper. Make sure the "ink" penetrates the paper. 

  3. Wait for the paper to dry

  4. To reveal the message, you may need the help of an adult. I got good results with a hair dryer. Alternatively, turn your toaster to the lowest heat setting and carefully hold the paper over the heat. Some methods suggest holding the paper up to a high wattage lamp.

The Science

The heat reacts with the lemon or lime juice or vinegar in a process called oxidation turning it brown.

Further investigation

  • Does it matter what type of paper you use? Newsprint vs normal photocopy paper

  • What "ink" is better: vinegar or juice? I got better results with lime juice.

​

bottom of page