Expert: Paul Soderman - 4/22/2008

Question
What is the best way to keep an ice cube from melting?
What do i have to put in on? (sugar, salt, coffee...)
thank you

Answer
Diego
This isn't exactly aero engineering, but I will take a shot at this.  The best way to keep ice from melting is to insulate it or keep the surrounding temperature below 0 degree centigrade.  I assume you are asking how can you delay ice from melting if the temperature around it reaches 0 degree or more (no insulation allowed).  Of the three substances you mention salt is the worst because it will melt ice.  You don't want to put the ice on salt.  Sugar is not quite so bad, but as the ice starts to melt the sugar will dissolve in the water and that should speed the melting process slightly.  So I would say coffee is your best bet.  It is not quite so readily dissolved and might provide some insulation.  Better yet would be Styrofoam or some other substance that does not transmit heat well.
Paul