[ar:MP3 同步字幕版(美音)]
[ti:Waves]
[by:更多学习内容,请到yingyu.chazidian.com搜索“新概念”]
[00:00.37]Lesson 40
[00:02.24]Waves
[00:09.08]What false impression does an ocean wave convey to the observer?
[00:15.37]Waves are the children of the struggle between ocean and atmosphere, the ongoing signatures of infinity.
[00:23.26]Rays from the sun excite and energize the atmosphere of the earth, awakening it to flow, to movement, to rhythm, to life.
[00:33.29]The wind then speaks the message of the sun to the sea
[00:37.20]and the sea transmits it on through waves--an ancient, exquisite powerful message.
[00:45.48]These ocean waves are among the earth's most complicated natural phenomena.
[00:51.45]The basic features include a crest (the highest point of the wave),
[00:56.13]a trough (the lowest point), a height (the vertical distance from the trough to the crest),
[01:03.67]a wave length (the horizontal distance between two wave crests),
[01:08.99]and a period (which is the time it takes awave crest to travel one wave length).
[01:16.21]Although an ocean wave gives the impression of a wall of water moving in your direction,
[01:22.46]in actuality waves move through the water leaving the water about where it was.
[01:29.36]If the water was moving with the wave,
[01:32.06]the ocean and everything on it would be racing in to the shore with obviously catastrophic results.