This is a reasonably safe way to heat the paper without risk of burning and it works well to reveal the message. The paper containing the message can be placed onto a white (ceramic) tile and the white tile can then be placed onto a hotplate.

An easy way to reveal these types of messages is to iron the paper gently. Most invisible inks are made visible by heating the paper. Avoid using lined paper to write your invisible message, for the same reason. Do not use a fountain pen since this ink could run into your invisible ink and make it visible. Write another (not secret) message on the paper with ballpoint pen, pencil or crayon, so it doesn’t appear to be blank and meaningless.Let the message dry in the air or use a hairdryer. Use the ink by writing your message with it using a paintbrush, spill, cotton bud, straw with a cut end to make a nib, or toothpick with cloth wrapped around it.The tiles heat up but protect the paper from burning.) White tiles (For using on the hotplate.Paintbrushes (and/or straws, cotton buds, spills).Sucrose (table sugar) solution (1 tsp in 10 cm 3 water).Soapy water (or 0.1 M sodium carbonate).Baking soda (sodium bicarbonate) (or 1 M sodium hydrogen carbonate).Heat-activated invisible inks Equipment:Īny of the following for your invisible inks: How you reveal the message depends on the ink you used. It would be good to use different types of ink as advised by your teacher. Pass the message to another group who will write an answer to the question and pass it back to you to develop. Use one of the methods below to write a question on a piece of white paper. Like all good science-artists, you decide to investigate further… You wonder if there is a way of writing with an ink that is only visible under certain conditions. You have been tasked by King Agis of Sparta to develop a way of delivering secret messages to his armies, which would be unreadable if they fell into the enemies’ hands. It is 410BCE and the Ionian (or Decelean) war, between Athens and Sparta has been raging for four years. Using my scientific knowledge to explain how changing the conditions the inks are under affects their visibility.Changing the conditions of the invisible inks to see if messages become visible.Writing messages with a variety of substances which can be used as invisible inks.RSC Yusuf Hamied Inspirational Science Programme.Introductory maths for higher education.The physics of restoration and conservation.

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