Video Description:   Find out how rocks brought to Earth by the Apollo astronauts have helped NASA learn more about the rock cycle. Compare igneous, sedimentary and metamorphic rocks found on Earth to three types of rocks found on the moon.     Video Length:  4:08.NASA eClipsTM is a suite of online student-centered, standards-based resources that support instruction by increasing STEM literacy in formal and nonformal settings.  These free digital and downloadable resources inform and engage students through NASA-inspired, real-world connections.NASA eClips Our World videos (grades 3-5) help students understand the differences between science (the natural world) and engineering (the designed world).  These video segments supplement elementary learning objectives not only in science, technology, engineering and mathematics, but also in reading, writing, visual and performing arts.