我找了下 只有 The Color of Snow 啊。。。。你是第几篇的啊？？[00:50.77]The Color of Snow[00:53.88]Generally, the color of snow appears white.[00:57.87]This is because the light we see from the sun is white. [01:02.17]Most natural materials take in some sunlight. [01:06.09]This gives them their color.[01:08.45]However, when light travels from air to snow, [01:12.31]some light is sent back, or reflected.[01:15.81]Snow crystals have many surfaces to reflect sunlight.[01:20.30]Yet the snow does take in a little sunlight.[01:23.99]It is this light that gives snow its white appearance. [01:28.34]Sometimes, snow may appear to be blue. [01:32.32]The blue light is the product of [01:34.19]a long travel path through the snow. [01:37.49]In simple terms, think of snow as a filter. [01:41.42]A filter is designed to reject some substances, [01:45.03]while permitting others to pass through.[01:48.22]In the case of snow, all the light makes it through [01:51.76]if the snow is only a centimeter thick.[01:54.75]If it is a meter or more thick, however, [01:57.69]blue light often can be seen.
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