| [00:01.54] |
Lesson 40 |
| [00:03.21] |
Waves |
| [00:10.91] |
What false impression does an ocean wave convey to the observer? |
| [00:17.55] |
Waves are the children of the struggle between ocean and atmosphere, the ongoing signatures of infinity. |
| [00:26.32] |
Rays from the sun excite and energize the atmosphere of the earth, awakening it to flow, to movement, to rhythm, to life. |
| [00:36.58] |
The wind then speaks the message of the sun to the sea |
| [00:40.58] |
and the sea transmits it on through waves--an ancient, exquisite powerful message. |
| [00:48.64] |
These ocean waves are among the earth's most complicated natural phenomena. |
| [00:54.50] |
The basic features include a crest (the highest point of the wave), |
| [00:59.77] |
a trough (the lowest point), a height (the vertical distance from the trough to the crest), |
| [01:07.89] |
a wave length (the horizontal distance between two wave crests), |
| [01:13.45] |
and a period (which is the time it takes awave crest to travel one wave length). |
| [01:19.92] |
Although an ocean wave give the impression of a wall of water moving in your direction, |
| [01:25.99] |
in actuality waves move through the water leaving the water about where it was. |
| [01:32.43] |
If the water was moving with the wave, |
| [01:35.08] |
the ocean and everything on it would be racing in to the shore with obviously catastrophic results. |
| [01:42.76] |
An ocean wave passing through deep water causes a particle on the surface to move in a roughly circular orbit, |
| [01:51.32] |
drawing the particle first towards the advancing wave, then up into the wave, |
| [01:57.22] |
then forward with it and then--as the wave leaves the particles behind--back to its starting point again. |
| [02:05.22] |
From both maturity to death, a wave is subject to the same laws as any other 'living' thing. |
| [02:13.11] |
For a time it assumes a miraculous individuality that, in the end, is reabsorbed into the great ocean of life. |
| [02:22.79] |
The undulating waves of the open sea are generated by three natural causes: |
| [02:28.83] |
wind, earth movements or tremors, and the gravitational pull of the moon and the sun. |
| [02:37.07] |
Once waves have been generated, |
| [02:39.21] |
gravity is the force that drives them in a continual attempt to restore the ocean surface to a flat plain. |
