Author Topic: Natural Phenomena  (Read 128854 times)

studentforever

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Re: Natural Phenomena
« Reply #750 on: October 20, 2017, 05:43:23 am »
Thanks. I've posted this on the news forum of my Egyptology class!

mapurves

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Re: Natural Phenomena
« Reply #751 on: November 06, 2017, 08:22:23 pm »
From USCG Cutter Northland, 12 July 1938

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At 5:30, in Lat. 67o 27'N, long. 167o 40'W entered area of local magnetic disturbance and determined the magnetic variation to be 9-00E, by sun azimuth, gyro compass, and flying-bridge magnetic compass. Similarly in Lat. 67o 18'N Long 167o 50'W magnetic variation is 7o-00E, and in Lat 67o 07'N, Long 167o 55'W magnetic variation is 10o-00E.

That's the first time I've seen that.

mapurves

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Re: Natural Phenomena
« Reply #752 on: November 09, 2017, 06:35:16 pm »
From USGC Cutter Northland, 8 September 1940

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1845 - Measured height of ice berg off Disko Island (69.75,  -53.50) by means of four point bearings, distance abeam and sextant angle. Height so measured was 404.6 feet.

That's a fair chunk of ice, especially considering that only 10% of it is above water, if it's floating, that is.

Randi

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Re: Natural Phenomena
« Reply #753 on: November 09, 2017, 06:50:39 pm »
For more details...
About 7/8ths of an iceberg is below the water line. This figure is approximate. Although icebergs are similar, not all are the same. Varying factors are iceberg density, water density etc. Keep in mind we are talking about an iceberg's mass. Due to irregular iceberg shapes, icebergs may have varying heights out of the water, but mass is relatively consistent.