About: http://webisa.webdatacommons.org/417349399

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	In short, there are two main reasons: there are different types of glass and secondly, marbles are spheres.Uranium Marbles that Glow in the Dark.
http://www.w3.org/ns/prov#wasQuotedFrom	physicscentral.com