CHEM CLASS
'(<a href="http://www.j-archive.com/media/2007-02-05_J_24.jpg" target="_blank">Jon of the Clue Crew gives the clue from behind a lab table.</a>)  When put on paper, graphite's lubricant properties <a href="http://www.j-archive.com/media/2007-02-05_J_24a.jpg" target="_blank">reduce this force</a> that resists relative motion'
friction