So remember, hydrophilic is water loving and hydrophobic is water hating. So what happens is when we place them into a solution that contains water as a solvent. So these are the water molecules here. These blue sections will tend to point on a surface, lie on the surface, while these red sections, these amino acids that contain hydrophobic side chains, will tend to aggregate at the center and form the core of that protein. So a protein in an aqueous environment will have a hydrophobic core and a hydrophilic surface. Now, if we go into that core, inside that core, we have many of these hydrophobic nonpolar side chains that are packed together.