Water is a polar molecule, meaning that it has a positive end and a negative end. This allows it to attract and dissolve other polar molecules. Nonpolar molecules, on the other hand, do not have a positive or negative end, so they are not attracted to water and do not dissolve in it.

Some examples of polar molecules that dissolve in water include:

* Sugar

* Salt

* Soap

* Alcohol

Some examples of nonpolar molecules that do not dissolve in water include:

* Oil

* Grease

* Wax

* Rubber