Hydrogen is a highly flammable chemical element which occurs in great abundance throughout the universe. In fact, hydrogen makes up approximately 75% of the universe, by volume, and it appears in a very large number of compounds, especially those which make up various organic materials. Many people are familiar with hydrogen as a potential fuel source, thanks to its promotion as a potential alternative fuel, and all of us consume hydrogen every day, in the water we drink and the foods we eat.

The atomic number of hydrogen is one, and it is identified by the symbol H on the periodic table. Hydrogen is a unique standalone element, not classified with any other elements. Many scientists think of hydrogen as a kind of elemental building block, since its simple structure is the basis of so many things. The colorless, highly flammable gas has a number of industrial uses, especially in the refining of petroleum products.

The history of the discovery of hydrogen is quite lengthy. Like other gases, hydrogen rarely appears in a pure form on Earth, and it took some time for people to understand that hydrogen was an element. Hydrogen gas was described as early as the 1400s, when experimenters combined acids and metals to produce a flammable gas. In 1671, Robert Boyle described this reaction in more detail, but it was not until 1766 that Henry Cavendish recognized hydrogen as a true element.

In 1783, Antoine Lavoisier proposed a name for the new element, “hydrogen,” after the Greek hydros for “water” and genes for “born or formed.” Lavoisier recognized that when hydrogen was burned, it produced water as a byproduct, through the combination of hydrogen and oxygen in the air. Thus, the element in a sense gives birth to water. Once hydrogen was fully recognized as an element, it began to be extracted from various natural sources and used in an assortment of fields.

Hydrogen is dangerous, as most people who know about the fate of the Hindenburg are aware. It was originally used as a lifting agent in balloons and zeppelins because it was so light, but the explosive nature of the gas led to the proposal of helium as a more stable and safe replacement. Since hydrogen is so reactive, it must be handled with care to avoid unfortunate and explosive situations. Fortunately, few people work directly with pure hydrogen, and those who do are carefully trained.