Nature’s Notes: versatility, usefulness of sand is staggering

The recent flood brought thousands of Iowans into contact with one of nature's most common and useful items — sand.

Sand kept the river at bay, and it was heartening to see so many volunteers filling and lugging sandbags as city workers hustled to fill HESCO barriers. The amount of sand used to ward off the flood is staggering. A few hundred grains in a single layer cover a quarter of a square inch. A handful holds tens of thousands of grains. Multiply that by the number of handfuls it takes to fill a sandbag and then multiply that by the 30,000 sandbags used and the number of sand grains used to fight high water is staggering.

Fortunately sand is common all over the world. It can be comprised of any tiny hard material, even sea shells ground up by the surf. However, most sand is composed of silicon and oxygen and was formed when glaciers ground up solid rock. Sand is often moved by wind or current. It usually is deposited in layers of unified grains. Large heavy grains fall to the bottom with lighter smaller grains on top. Sand dug from the same strata will be composed of same sized grains.

Few items in nature are as useful as sand. It is the main ingredient in concrete, provides silica used to make electronic chips, is the raw material of glass, smooths wood and metal when used as an abrasive, keeps cars from skidding on icy roads, and, of course, is stuffed into sandbags. When compressed together by nature sand grains form sandstone used to create beautiful buildings. Northeast Iowa sand is mined and used in the fracking process to extract oil and gas from deep in the earth. Children love making sand castles at beaches and backyard sandboxes.

Often sand is composed of grains of quartz. When viewed under a magnifying glass or low power microscope miniature sparkling gems greet the eye. When billions of grains are heaped and sculpted by the wind dunes of fascinating shapes are formed.

Thanks go to the thousands of volunteers who each hefted millions of sand grains to build barriers that kept Cedar Rapids dry.

Marion Patterson is an instructor at Kirkwood. Rich Patterson is the former executive director of Indian Creek Nature Center in Cedar Rapids.