spherical mirror

A spherical mirror is a curved mirror shaped like a small piece cut from a hollow sphere, with its reflecting surface curved either inward or outward.

• Spherical mirrors aren't literally sliced from a glass ball — they're made by grinding and polishing a flat piece of glass into a curved shape, then coating one side to make it reflective.
• A shiny metal spoon is a handy everyday spherical mirror: its inner curved bowl and outer curved back behave completely differently, previewing concave and convex mirror behaviour without needing any special equipment.
• Unlike a flat, plane mirror, which always shows a same-size, upright reflection, a spherical mirror changes the size and sometimes the orientation of the image depending on how far the object is from it.
• Spherical mirrors split into exactly two types based on which way they curve — concave (curving inward) and convex (curving outward) — and that single difference in curvature is what drives everything else about how they behave.