Light and Invisible Ink Exploration Pack - Set Of 10 With DVD. This set of four activities investigates how light is used in technology products. Each activity has deep content and unique materials so users can explore science concepts using STEM methodology. Pack Sets, designed for use by an entire class, include 10 sets of hands-on materials for one activity and a DVD with extensive content for all four activities. The DVD contains: Teacher and Student Guides, Background Information, Powerpoints and Videos, Glossary, Worksheets.