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BIG ENCYCLOPEDIA FOR CHILDREN AND ADULTS
What gives our eyes a certain color? Detailed answer
Directory / Big encyclopedia. Questions for quiz and self-education Did you know? What gives our eyes a certain color? The eye is one of the most remarkable organs of our body. It is a kind of camera, with an adjustable opening to let in light, with a lens-lens that focuses the light waves to form a visual image, with a sensitive film on which these images are imprinted. But we will not discuss here, as we see, but we will talk a little about the structure of the eye itself. Its shape is almost perfectly round, only slightly convex in a place that allows light to pass into the eye. This bulge is covered by the cornea. The cornea is transparent. It refracts light rays when it hits the eye. Since it protects the eyes, it is very sensitive. If dust or dirt gets on it, we will immediately feel it and try to remove foreign particles as soon as possible. The "film" is the retina. It consists of ten very thin layers of cells and lines the entire inside of the eye. In order to regulate the access of light, the eye has an iris and a pupil. The iris is the colored circle in the eye, and the pupil is the black dot at its center. The size of the pupil is regulated by the iris, which narrows the hole to the size of the eye of a needle in bright light and, conversely, expands it at dusk. Immediately behind the iris and pupil is the lens, which is very similar to the lens of a magnifying glass. The lens is elastic and can adjust depending on how far or close we are from the object in question. It is in the lens that light rays are refracted to come into focus on the retina. When we look into a person's eyes, the first thing we notice is the color of the iris. It has a coloring pigment to protect it from light. Most of the pigment is located on the back of the iris, and there is almost none in its front. Since the upper shell of the eye is transparent and absorbs the red and yellow waves of the light spectrum, the light reflected from the part containing the pigment appears blue. The blue color is simply a reflection of the pigment from the back of the iris. If the pigment does not begin to be produced over the years by the upper part of the iris, it will continue to look blue. But if the pigment still begins to form in the upper part, then the shell becomes brown. Author: Likum A.
Is all rice white? Nearly half of the world's population lives entirely or partially on a rice diet. In some Asian countries, each person eats from 90 to 180 kilograms of rice annually. Only threshed rice is called coarse rice. In this state, the rice is still covered with a rough shell. It must be removed before rice is cooked. Rice without this coarse shell is called brown rice. It is covered with a brown husk called bran. It contains the richest supply of vitamins and mineral salts that rice grains generally have. However, brown rice does not keep as long as white rice. Most people prefer white, well-threshed, polished rice to brown. When the rice is polished, the husks and underdeveloped grains are removed by passing them through a shelling machine and the surface of each grain is carefully worked. When threshing and processing is completed, the rice has a white and smooth surface. In addition to ordinary polished rice, there is also rice, also processed, but slightly darker than polished. It contains more vitamin В and mineral salts. For further processing, this rice is soaked in water at a temperature slightly below boiling point, and then it is steam-dried under pressure. This process is called scalding. Vitamins from the wetted shell penetrate the grain during this treatment. Rice originated in southern India, where it has been growing for thousands of years. From there it spread to the East, to China more than 5 thousand years ago. Prior to the XNUMXth century, rice was unknown in North America.
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