Eric Faulson9 age 9, of W illiamsport, PA, for,his question:

How small is a molecule?

A molecule is a bundle of atoms and the average sized atom measures about 100 million to the inch. The size of the molecule depends upon the number and size of the atoms it contains. The smallest molecules are made from two small atoms. The largest contains many thousands of atoms. But even the largest molecule is too small for our eyes to see. Some of the up‑to‑date microscopes, however, can enlarge a molecule and show us its picture.

Some of the biggest molecules are viruses. One of these is the polio virus which is a. round ball made from thousands of atoms. The electron microscope can enlarge this big molecule 180,000 times. A picture of this enlargement shows a round pom‑pom a little less than a quarter inch in diameter. Scaled down to its proper size, it would take three quarters of a million molecules of this size to measure one inch.

Most things around us are made of small or medium sized molecules. A molecule of table salt, for example, is a tiny bundle of two atoms, Every atom of table salt is made from one atom of sodium and one atom of chlorine. This is the smallest possible particle of table salt. If we broke the molecule apart, it would no longer be a particle of salt.

Table salt, as everybody knows, is made from crisp white grains. Perhaps we might think each one of those grains is a molecule. Not at all. A grain of salt is made from a vast army of salt molecules. They tend to arrange themselves in a square‑sided crystal of neat lattice work. Many of these miniature cubes cling together to form a. single grain of salt. It is possible to estimate the number of molecules in such a grain of salt, The number would be 10, followed by 24 zeros.

Suppose we could divide the molecules in one grain of salt equally among all the people in the world. From this one grain of salt, every man, woman and child would get about 60 million, million molecules

Table salt is a good example of the magic that takes place when atoms form molecules. Chlorine is a greenish yellow gas and very dangerous. It irritates the throat and gives a feeling of suffocation. A deer breath of chlorine is poisonous and may prove fatal, Sodium is a waxy, silver‑white metal. It needs only air to burst into flame, which is why pure sodium must be kept under a liquid such as kerosene,

Our innocent table salt is made from these highly dangerous atoms. In the world of chemistry, this is an old story* For when atoms comb'ne to form molecules$ they tend to loss themselves. The molecules are very different from the original atoms.. A lot of atoms of one kind form an element, such as sodium or chlorine. A lot of molecules form a compound, such as table salt.