These regions are sometimes represented as being negatively charged and positively charged. Polar molecules are held together by forces of attraction between opposite charges on different molecules. Water molecules have electron rich regions on the oxygen atoms and electron poor regions on the hydrogen atoms. Thus, water molecules are polar and consequently they stick together because the positive region of one water molecule is attracted to the negative region of another. These interactions provide an explanation for the high boiling point of water.
Paper is made up of extremely long molecules called cellulose.
Cellulose is a polymer which means that it is made up of thousands of smaller molecules strung together like beads. These bead-like molecules that make up the cellulose chains are polar and, as a result, cellulose has many regions of high and low electron density. The fact that the long cellulose chains are aligned in one direction can be demonstrated by tearing a piece of newspaper. You will find that newspaper tears easily and along a fairly straight line if torn in one direction, but when torn at a 90o angle the paper will not tear along a straight line.