Simplify the following text for a Grade 9 native English-speaking person.
Original: In 1972 , John Bardeen shared the Nobel Prize in Physics with Leon Neil Cooper of Brown University and John Robert Schrieffer of the University of Pennsylvania for their jointly developed theory of superconductivity , usually called the BCS-theory .
Simplified: Bardeen worked together with Leon Cooper and Robert Schrieffer created the standard theory of superconductivity known as the BCS theory , named after them . For this work they shared the Nobel Prize in Physics for 1972 .