Conic sections – the reflective property (satellite dish, whispering gallery, telescope)

MathematicsVectors & Coordinate GeometryAges 15–16

Rays of light hit a mirror shaped like a conic section and you watch where they go after reflecting: rays parallel to the axis of a parabolic mirror all converge at the focus (satellite dishes, headlights); rays leaving one focus of an ellipse pass through the other focus (kidney-stone lithotripters, whispering galleries); rays aimed at one focus of a hyperbola bounce back toward the other focus (Cassegrain telescopes).