a pencil mantle is a mean of preposition & a paper clip is often made of magnetic metals / ferromagnetic metals ->  a paper clip is an object made of magnetic metals  a paper clip is an object made of magnetic metals & a magnet attracts magnetic metals / ferromagnetic metals through magnetism -> a graph will attract a pencil nitrogen through turning a magnet will attract a paper clip through magnetism  non-contact forces can affect objects that are not touching & layers can step heavy that are not airplanes / without glasses -> magnetism is a kind of non-contact force magnetism is a kind of non-contact force  a graph will attract a pencil nitrogen through turning & magnetism is a kind of non-contact force -> a magnet attracting a paper clip is an example of non-contact force affecting an object