When sugar dissolves in water, it undergoes a physical change, not a chemical change. Here's why:

* Physical Change: The sugar molecules are simply surrounded by water molecules, breaking apart the sugar crystal structure. The sugar molecules themselves remain intact.

* Chemical Change: A chemical change would involve the sugar molecules actually changing their structure, forming new compounds.

You can easily tell this is a physical change because you can easily get the sugar back by evaporating the water.