A visit to the toilet is included in Professor Phil Moriarty's explanation of 3D glasses. How do 3D films give us that three dimensional effect? Visit our website at http://www.sixtysymbols.com/ We're on Facebook at http://www.facebook.com/sixtysymbols And Twitter at http://twitter.com/#!/periodicvideos Sixty Symbols videos by Brady Haran Brady's other channels include: null (Chemistry stuff) null (Numbers and maths) null (Space stuff) null (Science and behind the scenes) null (Food science) null (Big science facilities) null (Favourite scientists)