Bending the Truth

Ever notice how your arm appears to shift at a weird angle when you immerse it in bath water? If so, you’ve witnessed how water can bend light. What you may not realize is that the lenses in your eyes are mostly water. Like prisms, they break up white light into different colors so that the images formed on the retina tend to be slightly smeared. This color smearing, called chromatic aberration, follows a well-defined pattern: blue light bends the most, followed by green, then red. Under normal circumstances, your brain compensates for this color smearing of light, and you don’t notice anything unusual.