The Naked Scientists

The Naked Scientists Forum

Author Topic: Vanishing/ Disappearing Ink PRANK  (Read 4573 times)

Offline israel.raphael

  • First timers
  • *
  • Posts: 2
    • View Profile
Vanishing/ Disappearing Ink PRANK
« on: 08/03/2009 11:19:45 »
Does any one know how vanishing ink used as a prank, the one that....splattered on someone's clothing and leaves frightening stains disappears within seconds is made?


 

Offline John Chapman

  • Hero Member
  • *****
  • Posts: 602
    • View Profile
Vanishing/ Disappearing Ink PRANK
« Reply #1 on: 08/03/2009 14:52:04 »
Hi israel.raphael

I don't know if this is the full answer but I once bought some cheap disappearing ink from a practical joke shop about 15 years ago. It seemed to be just methylated spirits. Not very convincing as ink but it did evaporate and disappear. Also not very healthy or safe to throw over someone's clothing. Particularly if they are smoking! I suspect that 'genuine' disappearing ink, like the stuff they used to throw around in The Beano and other kids comics when I was growing up, is either different stuff or, more likely, doesn't exist at all.
 

Offline John Chapman

  • Hero Member
  • *****
  • Posts: 602
    • View Profile
Vanishing/ Disappearing Ink PRANK
« Reply #2 on: 08/03/2009 14:58:29 »
Believe it or not, Wikipedia has an entry for disappearing ink. See it here.

The main paragraph says:

"Inks that are visible for a period of time without the intention of being made visible again are called disappearing inks. Disappearing inks typically rely on the chemical reaction between thymolphthalein and a basic substance such as sodium hydroxide. Thymolphthalein, which is normally colorless, turns blue in solution with the base. As the base reacts with carbon dioxide (always present in the air), the pH drops below 10.5 and the color disappears.[2] Pens are now also available that can be erased simply by swiping a special pen over the original text. Disappearing inks have been used in gag squirtguns, for limited-time secret messages, for security reasons on non-reusable passes, and for fraudulent purposes."
 

Offline John Chapman

  • Hero Member
  • *****
  • Posts: 602
    • View Profile
Vanishing/ Disappearing Ink PRANK
« Reply #3 on: 08/03/2009 14:59:07 »
Oh, and welcome to the site!
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8661
  • Thanked: 42 times
    • View Profile
Vanishing/ Disappearing Ink PRANK
« Reply #4 on: 08/03/2009 15:40:13 »
Anything alkaline enough to turn thymolphthalein blue would be rather corrosive. You certainly wouldn't want to get any in your eyes and I'd think twice about getting it on skin.
 

Offline Chemistry4me

  • Neilep Level Member
  • ******
  • Posts: 7709
    • View Profile
Vanishing/ Disappearing Ink PRANK
« Reply #5 on: 09/03/2009 03:07:30 »
You might want to try
feature=related at home. :)
 


The Naked Scientists Forum

Vanishing/ Disappearing Ink PRANK
« Reply #6 on: 09/03/2009 03:11:31 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums