What is Invisible ink?
{{Orphan|date=August 2010}} '''Invisible ink''' is a type of liquid that cannot be seen or read unless it is first activated. Chemical reactions, heat, [[ultraviolet]] light or special glasses are used to make invisible ink visible. It is used to send secret messages or for entertainment. Invisible ink pens are sometimes sold or used for prizes, usually with an ultraviolet light. ==More reading== * {{cite book |last1=Iggulden |first1=Hal |last2=Iggulden |first2=Conn |title=The Dangerous Book for Boys |date=2007 |publisher=HarperCollins |location=New York |isbn=978-0061243585 |page=149 |chapter=Secret Inks}} {{stub}} [[Category:Writing tools]]