Projected materials like overhead projectors, document cameras, and slides allow educators to convey information to large audiences. They require three things: the material being projected, a projector, and a screen. Document cameras can magnify and project both 2D and 3D objects. When creating PowerPoint presentations, teachers should use contrasting colors for text and backgrounds, with a standard font size of 32 and about 9 lines per slide. Digital images are made up of pixels representing brightness levels, while projected materials allow sharing information visually with groups.