PHYSICS / OPTICS: Animation: movie of a make-up or shaving mirror with varying curvature (changing concavity). Magnification varies with curvature.

This animation shows a concave spherical magnifying mirror (makeup or shaving mirror) whose curvature varies. The animation starts with the mirror at maximum useful curvature (if the curvature is increased beyond this amount then the image becomes distorted) and the curvature drops until the mirror becomes a plane (flat) mirror (e.g. a normal bathroom mirror). At the start of the animation (when the concavity is greatest) you can see how the mirror greatly magnifies the objects in front. As the mirror becomes increasingly flat so the magnification drops. When it is completely flat then the image is the same size as the object itself. This capacity to magnify objects makes these concave spherical mirrors useful for detailed tasks such as shaving or applying makeup. Real makeup mirrors often have built in lights. This animation is a sub-set of a larger animation showing the same mirror transforming from concave to convex.

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