tag:techtv.mit.edu,:Array/218918600 2007-10-21 19:30:09 -0400 MIT News Office <p>In this video, MIT researchers add ammonium chloride in solution to the tunable gel, changing the gel's color. Washing the ammonium chloride away returns the gel to its original color. <a href="http://web.mit.edu/newsoffice/2007/lightgels-1021.html">Full story</a><br />Video / Youngjong Kang </p> 37