Pepper. Soap. Water.

Who knew three simple things could be so fun? Oh the wonders of chemistry.

Intermoluecular forces are defined as the bonds between two molecules and intramolecular forces are the bonds between atoms within one molecule. The intermolecular forces in water include dispersion, hydrogen bonding and dipole. While soaps seem to have weak van der waals forces.

(Water molecule diagram)

Here, with the soap and water alone, the soap did not dissolve. It seemed to have sink straight to the bottom and stay there. This can be explained by the polar and nonpolar ends of the soap molecules. The polar ends unnoticably dissolved at the surface of the water while the non polar ends sank to the bottom. This type of substance is known as a surfactant. The polar ends were strong enough to break the surface tension of the water. The surface tension of water is due to cohesion of the hydrogen bonding. Cool stuff.

 Now here is where the pepper was added to illustrate the interaction between the soap and water. The pepper stayed at the surface of the water. As I touched the surface with my soap covered finger, the pepper molecules seemed to "explode" and immediately spread to the edges of the cup. This visulization of repulsion is due to the intramolecular forces within the soap as well as the water. The intramolecular forces impact the intermolecular forces between the water and the soap. The polar ends of the soap molecules immediately repelled the polar forces from the hydogen bonds in the water.