Invisible Universe (LSE) Invisible Universe: The Electromagnetic Spectrum from Radio Waves to Gamma Rays. GEMS Teacher's Guide, Grades 6-8 Students unveil our dynamic relationship with the Sun through a space-weather mystery, a mock mission from Earth's atmosphere to outer space, ultraviolet experiments, and more. This NASA-inspired unit focuses on the impact of electromagnetic energy and solar particles on Earth. CD-ROM included. For grades 6-8. Qty :