MnSTEP Teaching Activity Collection > MnSTEP Activities > Invisible Ink

Invisible Ink

Sarah Hanf, North Park Elementary, Columbia Heights, MN based on an original activity from Janice Vancleave's book "200 Gooey, Slippery, Slimy, Weird, and Fun Experiments"


This chemistry experiment allows kindergartners a chance to hypothesize what will happen when we paint pictures or write words in lemon juice and then painted the paper with a special solution. This is not only a good way to enhance literacy by writing words but also to question and wonder about the reaction of the two substances.

Learning Goals

Hypothesize what will happen when the 2 substances mix.
Observe what happens once the experiment is complete.
Reflect on why the result happened and brainstorm ways to change or adapt the experiment.
concepts ~ Two Materials mixing together can change each other. Safety necessary while doing experiments. How can we change the materials and retest to see if results are different.
Vocab Words ~ Iodine, Invisible, Safety Goggles

Context for Use

This will be done in a kindergarten classroom but could be used with older grades. It is a lab and requires set up and clean up. It should take about 30 minutes and you will need lemon juice and an iodine solution. This activity is not really connected to our Foss Science kits but will enhance students science skills and the inquiry process.

Subject: Chemistry
Resource Type: Activities:Classroom Activity
Grade Level: Primary (K-2)

Description and Teaching Materials

This lesson will be introduced by telling the students that today they will see how two different solutions react to each other. Lemon Juice and Iodine...have the class observe the 2 solutions and then brainstorm a class hypothesis list of what will happen when they mix together. Have table groups or lab groups put on safety equipment to stay safe and get started. First you paint the lemon juice in a picture or words on white paper. Allow to dry (you can use a hair dryer to go faster) and then paint on the iodine solution. When it is dry you will be able to see your message in white. Have the class discuss what happened and talk about why. Then have them guess what other solutions they could use and what the result might be. For another day set up the experiments they come up with! Tell the kids this is a way to make invisible ink =)

Teaching Notes and Tips

Do make sure the kids are wearing safety goggles, iodine is a poisonous substance and need to keep their hands away from their eyes. The message will show up best when iodine is dry.


The assessment will be informal observation based on their hypothesis, and adaptations of the experiments. Participation is required by all students.


There are no kindergarten Chemistry Standards = (
1. The Practice of Science 2. Scientific inquiry is a set of interrelated processes used to pose questions about the natural world and investigate phenomena.
Use observations to develop an accurate description of a natural phenomenon and compare one's observations and descriptions with those of others.

References and Resources