Metalloids are the class of elements in the Periodic Table of the Elements that separate metals from non-metals. The elements on either side of the metalloids are either metallic or non-metallic, while the metalloids contain properties of both. This allows interesting chemical reactions as well as chemical combinations that are not seen in true metals and true non-metals. For example, silicon is a semi-conductor, which means that it does not fully conduct electricity like copper, but can conduct electricity if the conditions are correct; silicon is therefore useful in computers and other technology where a varying conduction rate is important. Aluminium, which people commonly think of as a metal because of its use in beverage cans, is actually a disputed element; it is thought of as an "Other Metal" because of its non-metallic properties.