托福阅读素材:圆顶小屋
2017-09-27编辑: 环球教育整理来自: 环球教育
很多考生会抱怨托福阅读时间不够,还没完全理解文章就做题,正确率不高。其实这是我们对托福阅读素材不熟悉造成的,下面小编整理了一下托福阅读考试最新的素材,希望能帮助大家更加快速高效的备考托福。
托福阅读素材:圆顶小屋
内容回忆:
文章讲了冰屋的一些特点,包括怎么建造的。然后一段时间屋顶化了就要打开门 refreeze。冰屋是锥形的,不是半球,因为半球不好建,需要 support。
参考阅读:
An igloo (Inuit language: iglu,[1] Inuktitut syllabics ᐃᒡᓗ [iɣˈlu] (plural: igluit ᐃᒡᓗᐃᑦ [iɣluˈit])), also known as a snow house or snow hut, is a type of shelter built of snow, typically built when the snow can be easily compacted.
Although igloos are stereotypically associated with all Inuit,[2] they were traditionally associated with people of Canada's Central Arctic and Greenland's Thule area. Other Inuit people tended to use snow to insulate their houses, which were constructed from whalebone and hides. Snow is used because the air pockets trapped in it make it an insulator. On the outside, temperatures may be as low as -45 ° C (-49 ° F), but on the inside the temperature may range from -7 ° C (19 ° F) to 16 ° C (61 ° F) when warmed by body heat alone.
Snow igloos are built in the shape of a catenoid, which offers optimal ratios between the height and diameter of the structure to eliminate the structural tension which could otherwise cause it to implode or bulge. The stresses of snow as it ages and compresses against the igloo will not cause it to buckle because in an inverted paraboloid or catenoid the pressures are exclusively compressive.[10]
This design originates from the Central Inuit.[10] In applied mechanics, the equation for this type of structure is written y = a(cosh x/a- 1) where y is the height to any point in the surface, x is the horizontal distance to the same point, and a is a constant.[10]
Since stress is a force per unit area, if the walls are of uniform thickness the compressive stress is independent of wall thickness; thicker walls provide better insulation but do not strengthen the structure because of added weight.[12]
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