Styrofoam™ cups is what cups made out of polystyrene foam, or plastic #6, are commonly referred to. However, the term Styrofoam™ is a trademark of the Dow Chemical Company and is not used to make food products -- including cups, plates, take-out containers or egg cartons. Styrofoam™ is used for packaging materials such as foam peanuts or inserts in boxes around electronic equipment, along with materials for crafts.
Despite the fact that the term Styrofoam™ cups is technically incorrect, most people refer to these polystyrene cups that way. Most people purchase disposable cups because they are easy to clean up and do not need to be washed. If you stop and get a cup of coffee on the way to work in the morning, chances are it came in a polystyrene cup.
There is much debate over what type of disposable cups and plates are better for the environment. In general, if you can use a cup or plate made of glass or ceramic that can be washed and reused, that is the best choice. If disposable plates and cups are a necessity, though, most environmentalists advocate choosing paper first, then plastic. Styrofoam™ cups should generally be thought of as a last resort.
Some are also concerned with health issues from using polystyrene foam in food. It is possible for some of the chemicals found in the polystyrene foam to leach into food, which you would then ingest. Scientific studies are taking place to determine the health effects, if any, from ingesting small amounts of these chemicals. As a general rule, however, you should avoid microwaving any food or beverage in a foam container.
Another problem with using Styrofoam™ cups is that these cups cannot be recycled. Though polystyrene foam can be recycled in some areas, food products cannot. Styrofoam™ takes 1,000 years to degrade, which only means that the chemicals begin to break down leach into the groundwater and soil. It does not truly "biodegrade" away into nothing. Plastic cups can sometimes be recycled, which is obviously a better option.
Instead of using polystyrene foam cups for your morning coffee, consider purchasing a reusable travel mug. You can either make coffee or tea at home and bring it with you, or stop at your favorite coffee shop to have it filled. Some coffee shops will even offer a discount if you use their proprietary mug, and all you need to do is wash the cup at the end of the day. Unless it is absolutely necessary when you are having a party or small gathering, consider using reusable utensils, plates and cups.