Matter exists in various forms such as gas, liquid and solid. Arrangement of atoms in these forms gives them their characteristic physical properties like density, shape and color. If we subdivide the solid state into fine particles until we reach molecular dimension, we observe a spectrum of particles, say, ranging from millimeter to nanometer size. Colloids are concerned with the properties of matter involving characteristic length scales that range from 1 to 1000 nm (1nm = 10-9 meters). Grah...