Aim of the project The aim of the project is to make an invisible ink that can be viewed only by some persons. Basically, it is the old trick that I learnt in my childhood. It is a very interesting activity that can be tried with minimum of efforts and time. You do not need the help of any elder or any of the specialists for this project.
Materials required for the above activity
• A knife
• A bowl of water
• Any normal size paper to write on.
• Any feather of the bird or any other instrument such as a stick from the groom.
Procedure to make the invisible ink First of all, you squeeze out the lemon juice with the help of a knife. See that you take the help of an elder if you are a child. After this,add a little water that is equivalent to the amount of the lemon juice that you have squeezed out. After this, take the paper and keep it in an oven or on the pan with medium flame. See that the intensity of the fame is not too high as the paper shall burn. The aim if doing this is to make your paper look old as it shall turn brown when kept in an oven or on a pan. Take the quill from the feather of the bird or the stick from the groom. Use this instrument as a pen and write after dipping it in the lemon juice. There are various types of combinations that you can use. If you want to use a light colored ink, add a little more water that is just more than the lemon juice that you squeezed out. If you want it to be of darker color, add more lemon juice than the water. After you have written your secret message, take the paper and hold it above the candle flame for a time being. See that the paper is held sufficiently above the flame so as to prevent it from acquiring too much of heat. You shall see the secret message is now visible to everyone.
Explanation of the experimentThe basic reason for this is the difference in the boiling point of water and lemon juice. Water gets evaporated faster than the lemon juice that gets oxidized in the presence of the oxygen in the atmosphere due to which the juice turns brown in color. Hence, your message becomes clear and visible.
A word of cautionThe readers must not feel that this can be used as a mean to do cheating in the exams as you shall not have access to any of the heating sources in the exam center.
Children attempting the experiment must take the help of the elders as far as the heating of the paper and holding the candle is concerned.