How on Earth?! Bizarre Phenomena Observed on Our Planet

Quick Flip

Take out a magnifying glass and hold it an inch or so over this apple. Probably the only difference you'll notice is that the image is much bigger. Now for the magic trick. Walk several feet away from the computer screen and hold up your magnifying glass about one foot away from your eyes. Point it at the apple. (Gasp!) Viewed through your magnifying glass, the apple is upside down! Why? The answer is fairly simple. In a magnifying glass, both sides of the lens curve outward to form a double convex lens. This lens can give you two kinds of images, a "virtual image" and a "real image." When you magnify the apple by holding the lens "Sherlock Holmes style," an inch or so away from the screen, you are viewing the apple's "virtual image." The light rays which produce the image do not pass through the magnifying lens, but instead diverge (or spread out) on only one side of the lens. When you perform the "magic trick" and view the apple upside down, you are viewing the apple's real image. In a real image, the light rays reflected by the apple pass through the lens and are focused on the other side. When the light rays pass through the lens's first side, they are inverted, to produce the upside down image focused on the other side. Interestingly enough, when we view any object, it is the "real," upside down image, that our eye receives. Our mind turns it right- side up for us only once the image actually enters our brain. That's it for today's Quick Flip. (c) 2002 Jennifer L. Nielsen