Make secret messages that glow with Fizzics Education | Kids Science Experiments


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Secret Glow in the Dark Message

Secret Glow in the Dark Message

Follow FizzicsEd 150 Science Experiments:

You Will Need:

  • A Blacklight can be found at a hardware store
  • Petroleum Jelly (Vaseline)
  • Paper
  • A dark room


Secret glow in the dark science experiment - materials needed
1 Secret glow in the dark science experiment - rubbing vaseline on paper

Dip your finger into the petroleum jelly and write a message on the paper. Don’t tell anyone!

2 Secret glow in the dark science experiment - turning on the UV back light

Turn on the blacklight and turn off the lights in your room.

3 Secret glow in the dark science experiment - secret message on paper revealed under a UV black light

Can you read your message?


Why Does This Happen:

The visible light rang, for humans, is between the frequencies of 400nm and 700nm, and we see this as red and violet respectively. Black lights emit an invisible ultraviolet light called UV-A, which as less energy than the sunburn causing ultraviolet light UW-B.

Some chemicals can absorb energy from the invisible UV-A light and reemit it as visible light. These chemicals are said to be fluorescent and you can find a lot of these chemicals in and around your home. For example: in laundry detergent, nail polish, your driver’s licence and money.
All material are made up of atoms and within these atoms there exist electrons. These electrons move around the nucleolus of the atom, its centre, in orbits or ‘shells.’ Moving between one shell, or orbit, to another requires loosing or gaining energy. For an electron to move to a higher orbit it must gain energy and for it to fall into a lower orbit it must lose energy.

Fluorescence occurs when the UV-A light gives energy to electron and moves them to a higher orbit. Once the electrons lose this new energy they fall back to their original orbit, releasing the remaining energy as visible light.

Forensic scientist can use fluorescence of chemicals to link a crime scene to the guilt person!

For more information on forensic techniques check out the crime scene investigation link.

Learn more!


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