hydrophobic

A hydrophobic effect is an effect displayed by hydrophobes showing the tendency of nonpolar substances to repel water molecules. A typical rule dealing with polarity in chemistry states that like attracts like, which means that a polar substance/solute will dissolve in another polar substance/solvent and the same applies with nonpolar substances. A nonpolar substance such as oil will not mix with water because water is polar. In biology, the hydrophobic effect is important in protein folding and forming lipid bilayers among other things. In one picture, the density and hydrophobicity of each substance keeps it from mixing together and in the other picture is a drop of water (polar) on the nonpolar surface of a leaf.