We now want the milk to maneuver somewhat. To do this large changing milk science experiment requires some washing up liquid or 'dish soap'. Get a cotton wool ball and dip it down into the soap - don't put to much soap about it, you don't want the swab to become dripping in soap. Carefully dab the cotton swab into one of several food coloring's in the soap and contain the swab there. Bang! Watch large explode outwards in concentric circles - very pretty.