About: http://webisa.webdatacommons.org/404515635

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	Frictional machines rely on the fact that some insulating substances such as glass, sulfur, and resin become electrically charged when rubbed vigorously.
http://www.w3.org/ns/prov#wasQuotedFrom	imss.fi.it