Forehead Thermometer: How Liquid Crystals Work

[The Worry Boy]

Yoy guys, I am working on an invention recently which is related to liquid crystals. I want to know how liquid crystals in a forehead thermometer works. Or basically, how a forehead thermometer works! Thx guys!

 

[mgb_phys]

They are simply a chemical mixture that changes colour at different temperatures, you can make the stuff yourself failry easily - see http://www.mrsec.wisc.edu/Edetc/nanolab/LC_prep/index.html

 

[chemisttree]

The device is explained here. Liquid crystal terminology can be found here. The cholesteryl ester based liquid crystals are termed "Chiral" liquid crystals.