how do you make invisible ink, like the one in the national treasure? i need this for my science project?

Answer 1

You can make a very basic invisible ink using just lemon juice. When the juice dries, it is invisible. To read the invisible messag, hold the paper up to a light bulb; the heat from the bulb will darken the message (be careful not to set the paper alight).

You can also use baking soda in the same way; disolve one part baking soda in two parts water.

If you want to be ambitious with your project and are able to obtain a small amount of silver nitrate: use sodium chloride in solution (table salt in water) to write a message. You can then develop the message by spraying silver nitrate in solution onto it.

To make your project more interesting, write messages using both lemon juice and sodium chloride, to demonstrate different re-agents (heat and silver nitrate). You could also write messages - over the top of the invisible ones - using a ball-point pen, to demonstrate how so many secret messages were sent undetected during WWII (a blank sheet of paper is pretty suspicious).

Good luck with your project.

Answer 2

I think if you write with lemon, it is invisible but then it turns brown if you heat it.

Answer 3

For my opunion it is water using with a pen.Water trace can detect later I think.

Answer 4

I did this as a kid in school too. I don't exactly remember how but I bet you it's on wikihow.com.



Yeah , it's there.