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'Magic' writing experiment

Description

Messages or pictures are drawn on absorbent paper using a variety of colourless, dilute, aqueous solutions. These are invisible once dried but on spraying with suitable reagents the messages or pictures can be colourfully revealed.

Credits

:
This is an experiment from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry.
magic-writing-experiment



Apparatus Chemicals

For each demonstration:

Eye protection: goggles

Protective gloves (preferably nitrile)

Large sheet of filter paper (Note 1)

Beakers (100 cm3), 6

Small paintbrushes (Note 2), several

Spray bottles (Note 3), 3

Hair drier (optional) (Note 4)

Potassium hexacyanoferrate(II)-3-water, 5 g

Copper(II) sulfate-5-water (HARMFUL), 5 g

Ammonium thiocyanate (HARMFUL), 5 g

Iron(III) nitrate-9-water (OXISIDING, IRRITANT), 5 g

Lead(II) nitrate (TOXIC, DANGEROUS TO THE ENVIRONMENT), 5 g

Potassium iodide, 5 g

Ammonia solution, 2 M, 100 cm3

Phenolphthalein indicator solution (HIGHLY FLAMMABLE), a few cm3

Deionised or distilled water, 1 dm3

Refer to Health & Safety and Technical notes section below for additional information.

 


Read our standard health & safety guidance







Page last updated July 2016

Messages or pictures are drawn on absorbent paper using a variety of colourless, dilute, aqueous solutions. These are invisible once dried but on spraying with suitable reagents the messages or pictures can be colourfully revealed.

ADDITIONAL INFORMATION

This is a resource from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry. This collection of over 200 practical activities demonstrates a wide range of chemical concepts and processes. Each activity contains comprehensive information for teachers and technicians, including full technical notes and step-by-step procedures. Practical Chemistry activities accompany Practical Physics and Practical Biology .