Physicists have set up a new pitch drop experiment for students to explore the difference between solid and liquids. Known as the 'world's longest experiment', the set up at the University of Queensland was famous for taking ten years for a drop of pitch -- a thick, black, sticky material -- to fall from a funnel.<img src="http://feeds.feedburner.com/~r/sciencedaily/~4/WYG2FXp_VLk" height="1" width="1"/>
