Zinc is a metallic chemical element found in reasonable abundance around the world. It is classified in the transition metals, along with nickel and mercury, among others. The metal is used in a variety of alloys and compounds which have a range of uses, from sunscreen to fine art. Living organisms also rely on it as a valuable nutritional trace element; many foods are excellent sources, including seeds and whole grains.
Pure zinc is a bluish white, lustrous metal. It is extremely brittle at average room temperature, although when it is heated it becomes soft, malleable, and easily worked. When burned, it yields a bright blue to green flame, and the metal is reactive, combining readily with an assortment of other elements. On the periodic table of elements, zinc is identified with the symbol Zn, and the metal has an atomic number of 30.
Humans have been using zinc for thousands of years; the element was used extensively in India in particular. Around the 1500s, it began to be imported into Europe, where it was a costly and unusual metal. Allegedly, zinc was named by Paracelsus, after the German zinke, “jagged,” to describe the way it behaved in a furnace. By the 1700s, several European scientists had managed to isolate the element; there is some dispute over who did it first, although many people give the credit to Andreas Marggraf.
In alloys such as bronze, zinc makes the metal stronger and sometimes easier to work as well. It is also used in solders and in galvanizing. Zinc oxide, a well known compound, is a popular ingredient in sunscreen. Some batteries, pigments, and coins also contain this metal. Humans require around 11 milligrams of zinc each day, most of which they absorb through a variety of foods. A deficiency can lead to hair loss, diarrhea, and sores, while an excess can cause stomach cramps and anemia.
Pure zinc metal is not toxic, but the element should be handled cautiously in some circumstances. The fumes can be toxic for people who work with the metal while it's heated, and free ions can be very dangerous. It is important to wear proper protection when smelting and heating metals in general to reduce exposure to toxic fumes. People who are exposed to too much zinc may have difficulty taking in necessary dietary minerals, as the metal can block absorption. Therefore, excess can lead to substantial health problems if it is not addressed.
By Mary McMahon
Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a All The Science researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.