Invisible ink is a writing fluid that’s invisible when utilized to paper however could be revealed later by warmth, gentle, or chemical response. It has been used for hundreds of years to ship secret messages, and it’s nonetheless used at present for quite a lot of functions, together with safety, espionage, and leisure.
One of the frequent methods to make invisible ink is to make use of lemon juice. Merely write your message on a bit of paper with a lemon wedge, and permit the juice to dry utterly. The message might be invisible till it’s heated, at which level the lemon juice will caramelize and switch brown, revealing the message.
