Crossed Polarizers Black Out an LCD

Image/light can fade nearly to black. Ask students to predict what will happen. Rotate one polarizer while viewing screen/filter stack. Key idea: Polarizers only transmit one orientation of light; crossed axes block most light. Ask: Why can two clear filters become dark together? Safety and cleanup: Avoid twisting/pressing screens. https://www.csub.edu/~adzyubenko/Phys2120/Polarization_Lab_2017.pdf