Report Abuse. Calcium can exist in solid, liquid, or gas form, depending on the temperature. And anything which does not occur naturally is synthetic. The word has nothing to do with elemental properties, as far as I know.twitching_green_grasshopper Â· 7 years ago.olid, liquid and gas are states or phases of an element or substance. But most substances can exist in all three states depending on temperature and pressure.
The basic premise of the telescope tube is to align two lenses the appropriate distance from each other. For this telescope, the lenses are a concave convex (one side curved out and the other curved in) and a plano concave (one flat side and one side curved in). The plano concave lens is used as the eyepiece with the plano (flat) side facing the eye.
The type of vision problem that you have determines the shape of the eyeglass lens. For example, a lens that is concave, or curves inward, is used to correct nearsightedness, while a lens that is convex, or curves outward, is used to correct farsightedness.To correct astigmatism, which is caused by distortions in the shape of the cornea, a cylinder shaped lens is frequently used.n the past, eyeglass lenses were made exclusively of glass. Today, most eyeglasses are made of high-tech plastics. These new lenses are lighter, do not break as easily as glass lenses, and can be treated with a filter to shield your eyes from damaging ultraviolet light.