Write a letter in invisible ink

Although letter writing is a dying art in the day of the internet and email, it may still be fun to share a note written in invisible ink with your friend. This simple science project based on elemental chemistry allows you to keep a secret message for your friend a secret even as you write it all down on paper.

Here’s what all you will need – a lemon, a knife, a bowl, a brush, a candle, a matchbox, a piece of paper and your very own secret message. Now cut the lemon using the knife into two halves and squeeze the juice of the lemon into the bowl. You may like to enlist the help of an adult for using the knife.

Next dip the tip of the brush into the juice extracted and use it on the paper to write down your message. Once the message is completed you can place the paper down to dry off. As the lemon juice dries the message will become invisible. Then you can pass it on to your friend to read it.

Your friend will need the lit candle to slightly warm up the paper for the secret message to show up. Have an adult around so that the paper does not burn and the message end up in ashes. Make it an even more interesting science project by using different types of fruit juices to see if they can be used as invisible ink as well.

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