Many of us use the term Styrofoam as a reference to most plastic foam packaging. We include foam drinking cups, packaging peanuts and the white material that our appliances, toys and so many other items are packaged in. In fact, most of this is not Styrofoam. Styrofoam is a registered trademark of Dow Chemical for an extruded polystyrene foam material sometimes referred to as XPS. This material is always made in a sheet form and is generally the color blue. The primary use for Styrofoam is for building insulation although you may find it used in Geofoam applications or in block form in the hobby store. As Dow states on their website, "You can't drink coffee from a STYROFOAM cup. (There's no such thing.)"
The typical foam coffee cup and the most common white colored packaging foam is expandable polystyrene foam or EPS for short. This material is related to Styrofoam in chemical makeup but it is produced and formed in a different process. It is generally recycled separately from DOW Styrofoam or other XPS material. EPS can usually be identified by looking for the circular pattern on the surface created by the individual beads that are used to make the molded shape.