Hi, Welcome to Kid Fun. A place to share ideas of games and activities to play with children. Never hear them utter the words, 'I'm bored' ever again! Come and write for us and you will get a share of the revenue made, plus it's really fun. We are currently offering guaranteed bronze $5 awards for articles with at least 1000 characters, 3 images and at least 1 original image. So grab the kids together and let's have some fun :)
Use lemon juice to write invisible messages that appear when heated! These messages are the perfect addition to a secret spy game, or simply use them to marvel at how the message suddenly appears out of nowhere.
Materials Sheets of white paper
A few drops of water
Cotton buds or cotton pads
Juice the lemon and strain the juice into a bowl.
Add a few drops of water and stir through with a spoon.
Dip a cotton bud into the lemon juice solution. Here, I used a rolled cotton pad because all of the cotton buds seemed to have vanished! But it worked the same way.
Write a secret message with the lemon juice covered cotton bud onto the white paper.
Set the paper aside and allow the juice and water to dry completely.
How it works
Once the message has dried, take it to a lamp. Carefully hold the paper to the lamp to heat up the paper where the message is written.
Be patient here! The lamp only makes a small amount of heat, so it can sometimes take some time for the paper to heat up and for the message to appear.
If you want to check to make sure the experiment is working, an adult can carefully do the same process using the oven or stove top. Have a fire extinguisher and a bowl or 2 of water ready if you are doing this, just in case the paper catches fire On the stove top, turn on one of the jets and hold the paper above the jets until the message appears. In the oven, place the paper onto a baking tray and bake for a few minutes until the message appears.
INK! A message has appeared
There are 2 key parts to how the invisible ink works. First, mixing in the few drops of water will dilute the lemon juice slightly and make it very hard to notice when applied to the white paper. When the message dries you will barely be able to notice it.
The lemon juice is an organic substance that, when heated, oxidises and turns brown! A chemical reaction takes place when the lemon juice is subjected to heat that turns the lemon juice brown, so that you can see where the lemon juice has been when it is heated.
Things like orange juice, milk, honey, and vinegar are some other substances that work the same way.