Test_assessment knowledge optics #1 | MOON PHASES | ECLIPSES | LIGHT SOURCES | SHADOWS | UMBRA | Earth - Moon - Sun | Optics - Interactive Physics Simulations | Interactive Physics Animations | Interactive flash animation for optics learning - Interactive flash animation to understand why the Moon is not always the same. Physics and Chemistry by a Clear Learning in High School, Middle School, Upper School, Secondary School and Academy. PCCL