Simplify the following text for a Grade 10 native English-speaking person.
Original: In physics , specifically quantum mechanics , the SchrÃ dinger equation , formulated in 1926 by Austrian physicist Erwin SchrÃ dinger , is an equation that describes how the quantum state of a physical system changes in time .
Simplified: The SchrÃ dinger equation is a mathematical formula that physicists use to study quantum mechanics . It is a mathematical equation that was thought of by Erwin SchrÃ dinger in 1925 .