Are you obsessed with secret agents and espionage? Do you think detective work is cool?
Either way, this DIY lab experiment is for anyone that enjoys solving a good mystery!
Here’s what you need:
– one lemon
– small bowl or ramekin
– a cotton swab
– white paper
– hair dryer
Squeeze the juice from the lemon into a small bowl and add a few drops of water.
Dip one end of your cotton swab into the bowl until it is soaked in lemon juice.
Write a single word or short message with the cotton-swab on the white paper.
Allow several minutes to let the word or message dry and remove any remaining liquids from the area. Using your hair dryer on LOW HEAT, pass over the paper until the word you wrote in the lemon juice – aka invisible ink – is revealed!
The lemon juice was diluted by the water so it was very hard to see when you added it to your paper, but since it is an organic substance, it turned brown when heated.
Invisible ink is made by using a liquid – like lemon juice, orange juice, milk, honey, even wine – that reacts chemically in the presence of light heat and ultraviolet light!
Stay tuned for even more fun experiments on LabNotes!
These experiments are intended for inquiring young chemists and their adult supervisors. In all experiments, responsible adults should assist throughout to ensure proper safety precautions are followed. Eye goggles, gloves, etc. may be required.