Simplify the following text for a Grade 10 native English-speaking person.
Original: In this article , he presented the postulates of relativity , derived the Lorentz transformations from them , and ( unaware of Lorentz 's 1904 article ) also showed how the Lorentz Transformations affect electric and magnetic fields .
Simplified: A quantity invariant under Lorentz transformations is known as a Lorentz scalar .