Apertures are used every day, in telescopes, cameras—even the pupil of your eye is an aperture! But how do they work? Use this kit to clearly and simply demonstrate the principles and properties of various apertures. Create apertures using diagrams provided in the kit, and insert the apertures so as to limit the amount of light hitting a mirror—suddenly, blurry images become clear! Clarity comes at a cost, however, because the images get dimmer as successively smaller apertures sharpen them. Mirror provided in this kit has both a convex and concave side, allowing you to also illustrate the difference between virtual and real images by attempting to project both. Only one will be visible! Economical kit is fully reusable and includes concave/convex mirror, mirror holder, and aperture diagrams and materials corresponding to six f-stop numbers. Detailed instructions and student worksheet are provided.