Over the centuries a series of classic experiments in optics and chemistry--some of which you can find online at this site and try for yourselves--established the nature of the stars and our Sun.

http://coolcosmos.ipac.caltech.edu/cosmic_classroom/ir_tutorial/discovery.html
Herschel: The discovery of infrared

http://www.ipac.caltech.edu/
NASA's Infrared Processing and Analysis Center Infrared Astronomy web site.

http://www.ktca.org/newtons/11/infrared.html
From PBS's "Newton's Apple": infrared Radiation: Interesting at home experiment on infrared radiation using a television remote control to detect infrared radiation.