einstein´s relativity theory e=mc2 equation mass energy equivalence on green old grungy vintage wide wooden chalkboard

answer background blackboard blue board chalk chalkboard class classroom concept education einstein einsteins emc emc2 energy equation equivalence formula frame genius green grungy handwriting isolated learn lesson mass math mathematics mc2 old physics relativity research retro school science scientist seamless simple solution study symbol teach theory vintage weathered white wide wood wooden