NOTE: Free essay sample provided on this page should be used for references or sample purposes only. The sample essay is available to anyone, so any direct quoting without mentioning the source will be considered plagiarism by schools, colleges and universities that use plagiarism detection software. To get a completely brand-new, plagiarism-free essay, please use our essay writing service.
One click instant price quote
If you know where and when to look, you can treat yourself to a colourful display of atmospheric halves, spots and pillars. These images can tell you something about the clouds overhead and possible changes in the weather. All of these images are created by light shining through cirrostratus clouds. These clouds occur at an altitude of 6, 000 - 12, 000 metres.
They appear as a thin sheet or layer (strata) that is pure white. The layer of cloud is so thin (only 100 - 450 metres) that is doesnt obscure the sun or moon, so you should be able to see your shadow. Cirrostratus is made of many types of ice crystals. However, four crystal shapes are responsible for producing most of the commonly see halves-plate crystals, columns, capped columns and bullets. The most obvious halo is found around the sun. If the layer of cirrostratus is extensive, youll see an entire ring.
Within the layer of cloud, sunlight is striking and passing through the sides of randomly-oriented ice crystals. As the sunlight passes through each crystal, the light changes direction, or refracts. The radius of the hale depends on the amount of change in the direction of the suns light. Usually this is 22 degrees.
Since the sun is 1 / 2 of a degree across, the radius of the halo is 44 sun-widths. Occasionally you may see a second halo at 46 degrees from the sun (that is, with a radius of 92 sun-widths). This is produced by sunlight passing through both the side and bottom of each crystal. Moonlight will also produce a halo, around the moon, with the proper layer of cirrostratus. Another common optical effect is known as " mock suns" or " sun dogs" or " parhelia" (Greek for " with the sun" ). These bright spots on either side of the sun, outside of the halo, occur when sunlight passes through the sides of capped columns, bullets and plate crystals, when these crystals are arranged with their sides vertical.
The crystals wobble, diffusing and smearing the colours of the mock sun. You can see halves and mock suns more clearly if you block out your view of the real sun by holding your hand in front of it at arms length. Another spectacular optical effect is the solar pillar. This is a vertical shaft of light the same colour as the sun stretching upwards from the sun and is most often seen at sunset or sunrise. Its produced by sunlight reflecting of the base of plate and capped column crystals in the clouds. You can also see pillars in an ice fog, when its illuminated by stree lights, or airport runway lights, for instance.
The appearance of all these optical images is a good indication that the weather will change. Strong vertical air currents associated with low pressure storms carry moist air skyward, where the water freezes. High speed winds above the storm system push the ice crystals on ahead. When you see halves around the sun or moon, you can be sure of two things-there are cirrostratus clouds above and, in a day or two, the skies will darken with an approaching storm.
Free research essays on topics related to: crystals, layer, sunlight, ice crystals, quot or quot
Research essay sample on Quot Or Quot Ice Crystals
