Thionin - The Two-Faced Solution - Chemical Demonstration Kit
By: The Flinn Staff
Item #: AP8845
The Thonon the Two-Faced Solution Light-Activated Chemical Demonstration Kit is an activity enjoyed by students and instructors alike. Students study light-activated reactions and indicators. “Elegant” best describes this wonderful demo.
This item can only be shipped to schools, museums and science centers
“Elegant” best describes this wonderful demonstration. A large beaker containing a purple solution is placed on an overhead projector. Aluminum foil is placed under the beaker so only half the beaker will be exposed to direct light. Switch the overhead lamp on and in a matter of seconds, the side of the beaker exposed to the light turns colorless. The unexposed side remains purple. The intense light causes iron(II) to reduce thionin in an acidic solution. The thionin is photochemically reduced—a visible example of the conversion of light energy to chemical energy. Since the chemical solution can be used over and over again we have provided enough materials to prepare the solution three times. Both you and your students will enjoy this demonstration. Teacher Demonstration Notes included. Enough materials are included to perform the demonstration seven times.
Concepts: Light-activated reactions, indicators.
Time Required: 15 minutes
Chemicals Provided: Thionin, sulfuric acid solution, iron(II) sulfate.