A large block of Aluminum has a perfect cylindrical hole of diameter 3 meters. On top of the hole sits a perfect, solid glass sphere of diameter 3.05 meters. Your job is to get the glass sphere to traverse the hole in the block. Oh yeah, when you are done, the block and sphere are indistinguishable (macroscopically and microscopically) from their condition before you started. Is this possible?

Heating the block will increase the diameter of the cylindric hole.  The thermal expansion coefficient of aluminum is 2½ times that of  regular glass and six times that of Pyrex glass.  However, the temperature increase required to decrease the differential between the cylinder and the sphere far exceeds the melting point of aluminum based on standard initial temperature.

Even in the best case where the metal is heated and the glass is not, it would require a temperature increase of 735 °C for the diameter of the cylindrical hole to expand to 3.05 m.  The melting point of aluminum is only 660 °C. 

Posted by hoodat on 2007-02-08 16:57:30