Invisible Ink

Invisible Ink is a great science experiment that enables children to create invisible art and make it magically appear using lemon juice!

Materials Required

White glue
White crayons
Watercolours
Iron
Earbuds
Lime juice
White construction paper

What To Do

Take the white construction paper.

Activity 1

Squeeze out some lime juice in a bowl.
Take the earbuds, dip them into the lime juice and draw/write on the construction paper.
Now let them dry overnight.
The next day you can heat the iron and carefully apply it to the paper where you have written.
Slowly you will observe that your writings start to become visible.

Activity 2

Using white crayons, you can make art on construction paper.
Then using watercolours, discover the hidden messages and drawings.

Activity 3

Using the white glue, you can create your own piece of art on the construction paper.
Allow it to dry for a day.
The next day, you will find that the glue is dried hard and appears in an embossed form on the paper.
Now take the watercolour blocks and give a very light wash of watercolours.
Very soon you will find your invisible drawings to be visible in the paper.

The Science

Heat, oxidation-reduction, and acid-base reactions are a few of the reactions that can be utilised to reveal invisible ink. When an acidic or alkaline component of the ink can be seen by a particular chemical (indicator) that changes colour depending on whether it is in an acidic or alkaline environment, acid-base reactions take place. The usage of oxidation-reduction reactions, in which a chemical compound's colour varies based on its redox state, is analogous. The fact that some chemical substances are sensitive to heat or light and alter their colour when subjected to these conditions can also be used.

Making invisible ink visible can be accomplished in a variety of ways, including by applying heat, a specific chemical, or UV light, depending on the kind of chemical reaction the ink is based on. The secret message is revealed as a result of all these specific processes.

Hints And Tips

For the 1st activity, you can flip the paper and apply iron to it so that the chances of the paper getting burnt are less.
The iron should be set in the cotton setting.
Also, ask kids what other materials can they use to make invisible ink.
Citrus juices work best as invisible ink.
You can also try some cow’s milk, vinegar, almond milk, etc. to make invisible ink. Note down the observations for each ingredient you use.
The 2nd activity will give you instant invisible ink.
Kids can use this to write secret messages and exchange them with their friends. Then they can decode this message using watercolours.
This is a wonderful game that kids will enjoy playing.
In the 3rd activity, if you find making designs with glue to be difficult, you can pour some glue into squeezy bottles so that the kids can handle it easily.
You can encourage kids to make various designs, patterns, shapes, drawings, letters, and numbers through this invisible ink. This could be a very good start for the writing of the toddlers.
They could use this art to write some secret messages to their loved ones.
Let the kids explore and experiment with this activity with their own imaginations and combinations.