http://www.helium.com/channels/847-Physics.xml Helium.com Physics en-us Copyright Helium.com Wed, 09 Jul 2008 14:51:55 GMT Wed, 09 Jul 2008 14:51:55 GMT http://www.helium.com/knowledge/172632-sir-isaac-newton-one-mind-equals-many-discoveries Knowledge: Sir Isaac Newton: a life of physics Mon, 30 Jun 2008 14:13:28