How does lemon juice make the invisible ink effect?
Invisible ink is a substance used for writing that is invisible either when applied or shortly thereafter. While kids use it as a form of entertainment, the use of invisible ink was common among prisoners, spies and during times of war. Today invisible inks help in various industries, from hand stamps during events to verify admission to anti-counterfeiting practices. Lemon juice is inexpensive, and makes a handy invisible ink for kids—and the kids-at-heart.ApplicationLemon juice invisible ink is used by applying the liquid to paper using a swab, brush or other object, then allowed to dry. A visible message or drawing is usually written on the paper to further encrypt the message.Heat Makes the Image AppearHeat is used to reveal a message created using lemon juice as invisible ink. A light bulb or iron provides enough heat to cause a chemical reaction to occur with the lemon juice. The reaction causes the lemon juice to discolor so that the message can be seen.Why it WorksLemon juice
