An optical science activity from Science Buddies : The Magnifying Effect of a Water Drop

Have you ever studied an everyday object through a magnifying glass and been amazed at what you could see? Or have you ever noticed, for example in a swimming pool, that an object that is sticking out of the water looks different just above and just below the surface? In this activity you will learn a little bit more about both of these observations. Get ready to bend light, magnify letters and have fun with water drops all while getting a glimpse into how lenses work! Lenses are the key components in eyeglasses, contact lenses, binoculars and telescopes just to name a few devices. With this activity a homemade magnifying glass is only a drop away!

You see an object because light rays reflected from the object shine into your eye, creating an image on the retina inside your eye. Signals to your brain allow it to re-create the picture of the object.

A light ray bouncing off an object usually travels in a straight line to your eye. Things change when a transparent material, such as glass or water, gets in the way. When a light ray traveling through air enters such a material, it changes direction, creating a sort of kink. Another kink is introduced when the ray leaves the material. Therefore, the final image of the object in your eye might be different due to the changes in direction of the light on its way to your eye. Your brain is unaware of these kinks and expects an image created by rays that traveled in a straight line. As a result, it might reconstruct a picture that is different from the initial object. Your eyes and brain might have been fooled!

Lenses use these kinks to make objects look bigger or smaller, closer or farther away. A convex lens bends light rays inward, which results in the object being perceived as larger or closer. A concave lens bends rays outward; you get the perception that objects are smaller or farther away. There is no overall bending of light for a flat lens. You perceive the object as it is.

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