Acrylic is a useful, clear plastic that resembles glass, but has properties that make it superior to glass in many ways. Common brands of high-grade acrylic include Polycast, Lucite and Plexiglass.

There are two basic types of acrylic: extruded and cell cast. Extruded or "continuous cast" acrylic is made by a less expensive process, is softer, can scratch easier and may contain impurities. Cell cast acrylic is a higher quality acrylic and U.S. domestic cell cast is a good choice for applications that require the best. Imported cell cast acrylic is often manufactured to lesser standards.

Acrylic is used to make various products, such as shower doors, bath enclosures, windows and skylights. It is chosen over glass for many reasons. It is many times stronger than glass, making it much more impact resistant and therefore safer. Falling against an acrylic shower door will not likely break it. Baseballs that crash through glass windows will, in most cases, bounce off acrylic windows. Acrylic also insulates better than glass, potentially saving on heating bills.

Another great advantage of acrylic is that it is only half as heavy as glass. This makes working with acrylic much easier. It can also be sawed, whereas glass must be scored.

Adding to this favorable array of properties, a transparency rate of 93% makes acrylic the clearest material known. Very thick glass will have a green tint, while acrylic remains clear.

A unique property of plastic is its ability to be shaped. Bow-front aquariums are beautiful examples of acrylic's wonderful properties. There are also no seams in acrylic structures, as chemical welding at the molecular level actually "melts" seams into one piece of solid material. Seams that are welded and polished are invisible.

There are some misconceptions about acrylic, namely that it yellows, turns brittle and cracks over time. Though this might be true of very cheap forms of plastic, it is not so with acrylic. For example, the fighter planes of WWII have acrylic bubble-tops. Airplane windows are also acrylic. If taken care of, acrylic remains new looking regardless of age or exposure to sun. Some people worry that acrylic scratches too easily, but unlike glass, scratches can be easily buffed out of acrylic.

For all of its advantages, there are two disadvantages of acrylic: it is more expensive than glass, and if exposed to a direct flame it will melt and eventually burn.

Today acrylic is used more than ever. Virtually all major public aquariums now build display tanks out of acrylic. You will also find acrylic in malls, institutions, prisons, hospitals and commercial buildings. Acrylic just over one inch thick (32mm) is bullet resistant. The Presidential motorcade, the Pope's booth-vehicle, teller enclosures and drive-through window enclosures all feature bullet-resistant acrylic.

If upgrading the windows in your house, remodeling your bathroom, or adding a beautiful aquarium, consider acrylic. It may cost a little more than glass, but its sheer clarity, light weight and insulating properties make it a superior choice for many applications.