"D" IN SCIENCE
'(<a href="http://www.j-archive.com/media/2008-03-11_DJ_05.jpg" target="_blank">Kelly of the Clue Crew adds drops to a beaker.</a>) When you add food coloring to water, the motions of the dye's molecules causes it to <a href="http://www.j-archive.com/media/2008-03-11_DJ_05a.jpg" target="_blank">disperse</a>, eventually filling the glass evenly through a process called this'
diffusion (dilution accepted)