Ever wondered how invisible inks work wonders? 

Imagine this: You have got the opportunity to take part in a treasure hunt. In fact, you have been chosen as the leader of one of the teams. How will you secretly communicate with your team members? We have an idea for you: Let invisible ink do the talking! All you need to do is write a note on a piece of paper using an invisible ink, so that even if your opponent catches hold of it, they won’t be able to decode the message. Are you already intrigued with the idea? Well, you should definitely try it out sometime. For now, focus on how an invisible ink works its wonders. Natural agents such as heat, light and chemicals have the power to activate invisible inks. Here’s a low-down on different types of invisible inks. 

Heat-activated invisible ink 
As you can guess from the name, there are inks that are usually invisible and can only be seen when exposed to heat. These inks are made up of organic liquids (kitchen staples such as lemon juice, onion juice and vinegar), and once the written text dries on the paper, it soon disappears. Okay, so how do you make it visible? It’s simple. All you need to do is expose the ink to heat, such as under an iron or over a candle flame. This tends to activate the acids in the organic liquid (ink) and turns into a different colour, revealing the message.  

Chemically-activated invisible ink 
The invisible ink that activates when exposed to chemicals are made from chemical substances. Are you wondering how does this happen? Well, certain chemicals are naturally colourless until they are blended with each other. One such chemical should be used while writing the message, while the second chemical should be added by the receiver while decoding it. Once the second chemical is added to the first one, the colour slowly changes, thus revealing the message. How exciting is that? Give it a shot. Well, try writing a message in vinegar and then add red beetroot water on it while decoding. 

Light-activated invisible ink 
Have you heard of people complaining about invisible stamps, when they return from amusement parks? Turns out, these stamps are made out of invisible inks and are activated when exposed to light. These inks are made out of substances that are only visible when put under special types of lights like the UV ones. Light-activated invisible inks can be made out of laundry detergents containing brighteners.