Global Compass - how do they work
50,299
Published 2024-04-08
Standard Compass:
• In a standard compass, the North Seeking Pointer is typically a magnetized strip or disk made of a ferromagnetic material like steel.
• The magnetic needle is rigidly attached to the base or housing of the compass, typically by a pivot point.
• As the compass moves towards the magnetic poles (either the North Magnetic Pole or the South Magnetic Pole), the magnetic field lines become more vertical, causing the needle to dip or incline.
• When the needle dips too far due to the strong inclination of the magnetic field lines, it may drag or rub against the base of the compass housing. This friction can impede the smooth rotation of the needle and affect the accuracy of direction readings.
• Additionally, in extreme northern or southern latitudes, where the magnetic field lines are nearly vertical, standard compasses may exhibit erratic behaviour or become unreliable due to the excessive dipping of the needle.
Global Compass:
• In contrast, a global compass is specifically designed to mitigate the limitations associated with standard compasses, particularly in regions with extreme magnetic inclination.
• In a global compass, the North Seeking Pointer is attached to a small magnet in a unique manner that allows the magnet to tilt or dip without significantly affecting the orientation of the Pointer.
• By allowing the magnet to dip freely, the global compass can compensate for the vertical inclination of the magnetic field lines, ensuring that the Pointer remains relatively stable and accurate even in regions with strong magnetic dips.
• This design feature minimizes the risk of the needle dragging against the base of the compass housing, thereby maintaining smooth rotation and precise direction readings.
• Consequently, global compasses are better suited for navigation in diverse geographical locations, including polar regions, where standard compasses may struggle due to magnetic anomalies and extreme magnetic inclinations.
All Comments (21)
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Every video I think to myself, "Man I'm glad I found this channel".
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Some people are born to teach. I’m grateful to encounter them.
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That is fascinating, again you teach us about something that we knew nothing about and keep our attention because its so well presented. Thank you.
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Excellent as usual, thanks. Can't wait for the quantum electrodynamics talk. Best teacher I ever had.
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The Map Reading Company, Wow, this made my day brighter! Thank you!
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I live in New Zealand and it is very difficult to find a compass where the southern end of the pointer doesn't scrape. Even proper outdoor shops frequently sell compasses that have been balanced for the northern hemisphere (with a northern hemisphere DIP angle). When I try to tell them they look at me like I come from Mars. I go back to the shop a year later and they are still selling them. Using a compass with the wrong dip angle is incredibly annoying because you always have to monitor if it is scraping and thereby giving you a false bearing.
Enjoy your videos, any chance of one about the wonderful, but now discontinued, Silva 54 with the miniature sighting prism built into the housing. I used one in Antarctica to sight in a row of glacio poles, on a bearing. We swore that with care you could sight to 1/3 of a degree. Cheers. -
Completely not what I expected the difference to be. Many thanks for the explanation.
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Thank you.
Was in the US Army did land navigation, but never was taught about that. -
Damn man, I have NEVER seen a video about something I didn't know I was interested, catch me so hard in the first 35 seconds. Sir, you are hipnotic on another level.
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I discovered this myself, almost 30 years ago, when I was in college studying for an electrical engineering degree, and as a project developed a digital compass, which gave its best results when tilting down on the north end.
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I never knew that.
Every day's a school day.
Thanks. -
I like the little spherical compass that is suspended in liquid.
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Thank you for a great explanation of a little discussed area of compass behaviour. I liked your wooden lecturing aids.
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well I raised a question directly on this a couple of weeks ago, maybe that's not a coincidence to get a new video to directly answer it ... either way, thank you ... all very clear as always!
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Excellent presentation, clear and demonstrative. Cheers.
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The other advantage of many global needle designs is that they can be accurately read while running, canoeing, etc thanks to the stable, fast-settling needle (1-2 seconds or less)
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The best explanation of the differences that I’ve ever heard.
Now I want to know why lanyards are always to short- bugs the crap out of me. -
I just learned a number of interesting things, thank you!
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Great video. I thought I knew something about a compass, but this was new to me. Thanks.
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That was very well done. Nice and simple, and no useless music!👍 Good use of 'clunky' props.
