Unveiling the Secrets: Marking Cards With Invisible Ink

Unveiling Secrets: Marking cards with Invisible Ink

In the past, spies would use invisible ink to create secret messages. It may seem old-fashioned, low-tech in comparison to the high-tech communications we have today, but invisible writing can be used for a variety purposes.

In order to make invisible ink, you must first mix the ink. This is made from a liquid that is slightly acidic, such as lemon juice or vinegar, and water. This mixture can be applied to paper using a pen or even a brush. The message will appear when the paper is heated. You can either iron the paper or place it in the oven (with caution to prevent burning) or hold the paper over the light bulb.

Depending on the type of ink used, different acids are needed to make it visible. Citric acid in lemon juice, for instance, eats up the carbohydrates on the paper and causes them to carbonize, turning brown. Other invisible inks are revealed by spraying a special chemical on the paper or shining an ultraviolet light.

Students can improve their writing skills by using invisible ink. It is a fun way to practice. You can use this method to highlight an important skill you want students to improve, such as capitalization or writing complete sentences.