Karen A. Beitler
Students will often say something is large, or small without the understanding that size is relative to what an object is compared to. To help with the understanding of the size of an atom, comparisons are often employed. If an atom were the size of a basketball, then a dime of atoms would be the size of the entire planet, or if an apple were as big as the Earth, then each of the Earth's atoms would be the size of an apple. An atom is mostly empty space; therefore if the sun were a nucleus of an atom (protons and neutrons) then Mars would be the closest electron. Size is important to understand when polymers are described as large molecules. When atoms are bonded together they make molecules. If small molecules are repeatedly bonded together into large chains molecules then the small molecule is called a monomer and the large chain a polymer. A monomer is like a crystal of sugar and a polymer is like a bowl of spaghetti (starch). One long noodle would make a polymer chain of monomers, like a bowl of spaghetti, and this molecule would have specific properties. Spaghetti is a good analogy because you can think of spaghetti that is heated and cooked, soft and pliable and as the dry, hard, straight chains. Polymers are much the same. As more and more monomers become larger and more condensed polymers, the molecule becomes denser and more brittle, thus the properties change when heat is applied and molecules are lost.