Electron lenses may operate electrostatically or magnetically. Because the charges are separated, plasmas are electrically conductive and magnetically controllable. Magnetic bearing (magnetically levitated) and air bearing centrifugal compressors exist. Magnetic storage uses different patterns of magnetization on a magnetically coated surface to store information. To reduce the magnetic background noise, the measurements were made in a magnetically shielded room. This is electrically and magnetically similar, but has improved air cooling. The sculpture consists of an aluminum sphere magnetically levitated above a walnut disc. The linear-motor magnetically levitated train has a top speed of . The principle used in scanning a ferromagnetic measuring scale magnetically does not exhibit these deficiencies. In 2000, cryptochrome was proposed as the "magnetic molecule" that could harbor magnetically sensitive radical-pairs. It is also used for some classes of magnetically levitated bearings. Magnetically "soft" (low coercivity) iron is used for the cores in electromagnets. Magnetically driven ferroelectricity is also caused by inhomogeneous magnetoelectric interaction. Materials with low coercivity are said to be magnetically "soft". Snatoms are a molecular modeling kit where the atoms snap together magnetically.