fluorescence

the emission of light by a substance that has absorbed light or other electromagnetic radiation, a form of luminescence. 

color changing marshmallows
// Wednesday, July 19, 2023 Tom Kuntzleman
Jet-Puffed color changing marshmallows are an interesting new product that is available on the shelves of grocery stores through the end of September.1 The color of these marshmallows changes when exposed to heat: the blue version turns green, while the pink version turns orange.
text on green background: A Chemical Laser Show
// Saturday, December 7, 2019 Tom Kuntzleman
I recently developed a demonstration that I’d like to call “The Chemical Laser Show”.
How to make a better glow stick
// Thursday, January 8, 2015 Tom Kuntzleman
Happy New Year!  Did you know that 2015 is the International Year of Light (IYL)? IYL is a “global initiative adopted by the United Nations to raise awareness of how optical technologies promote sustainable development and provide solutions to worldwide challenges in energy, education, agriculture, communications and health1”.  IYL is sponsored by several organizations with interests in science and science education, including the European Physical Society, the Institute of Physics, the American Physical Society, and the American Institute of Physics.  You can find several lesson plans, videos and other educational resources on the IYL website2
// Saturday, October 19, 2013 Tom Kuntzleman
Halloween is a great time of year to do experiments with fluorescence. In the video below, we experiment with some fluorescent yarn.