The hydrogens in a water molecule are attached to the oxygen by polar covalent bonds. What makes the water molecules stick to each other to form a cohesive liquid? There are no more unpaired or lose electrons to aid in bonding. That's what makes the bond a non-chemical bond. This Powerpoint presentation explores the types and causes of several types of non-chemical bonds, including London dispersion forces, dipole-dipole attractions, hydrogen bonds, and metallic bonds.
Worksheets on this topic are available on my website at http://www.evanschemistrycorner.com.