Magic Light by YINING LU
1st Place - Natural Category
School: Beijing National Day School
Teacher: Homeschooled Physics
"Penny grass is a tiny, umbrella like grass. which cannot live without water. I took this picture just after it was watered in the morning. I was deeply impressed and attracted. It is colorful and glittering. The flowers in the droplet of water were formed by the refraction of light. This is a perfect example of the path changing of the light rays due to the different index of refraction of air and water. when light passed from one transparent medium into another, part of the incident light is reflected at the boundary. The rest changed their directions. The droplet is not a perfect spherical one owing to the gravity. It is much more like one planoconvex lens. The diameter is only half a centimeter around. The incidence light first reflected from the real flower into the water and changed direction and focused on the focal point to form the image. The droplet just like a convex lens. The position of the real flower and the droplet should be parallel to each other to get a clear and complete real image. We can see a sharp image, when the eye is placed behind the image. The sunflower is real and has three dimensions, so the focal planes are not only one. That is why the images are not quite the same as the object. The real images are upside down which can be explained by tracing the ray. The size of the image is depends on the distance between the flower and the droplets according to the lens equation. The beautiful flowers in the droplets can be seen is the coincidence of the right incidence angle of light, the right angle of my eyes. when I moved slightly, it disappeared like a magic. Beauty is everywhere, for our eyes, not the lack of beauty, but the lack of discovery! "