PHYSICS / OPTICS / OPTICAL INSTRUMENTS: Animation: movie of a magnifying glass with varying curvature. Magnification varies with curvature. Two magnifying glasses are shown that go through the same transformation. The upper one shows the lens in side view so that its varying convexity can be seen.
This animation shows a magnifying glass whose curvature varies. The animation starts with the magnifying glass lens at maximum curvature and the curvature drops until the lens becomes a plane (flat) glass. At the start of the animation (when the convexity is greatest) you can see how the magnifying glass greatly magnifies the letters behind. Notice the bulging lens in the side view at top. As the lens becomes increasingly flat, so the magnification drops. When it is completely flat (in the middle of the animation) then the image is the same size as the object itself. This capacity to magnify objects makes these convex lenses useful for detailed tasks.