explain what will happen to a sugar cube when it is placed in a glass of water.

2 answers

It will dissolve.

http://www.infoplease.com/cig/science-fair-projects/salt-sugar-dissolves-faster-different-liquids.html
This is because adhesive forces between the water molecules and the sugar molecules, along with cohesion with- in the liquid, allowed the water to move up the sugar cube tower against gravity. This process is called capillary action