What Are Things Made Of? Summary and Analysis

Long ago, many different societies came to the conclusion that everything was composed of different elements: earth, fire, air, and water. One Greek philosopher named Democritus, however, believed that things were made out of atoms—indivisible units of matter that could not be broken down any further. This turns out to be somewhat true, but most of the substances we see around us are compounds—collections of many different kinds of atoms. These compounds are known as "molecules," and may consist of just two atoms, or very many. Diamonds, for example, are crystals of millions of carbon atoms joined together in a single molecule. The atoms in this type of formation are all spaced out in the same way. Most metals are joined together in this way. Other types of matter...