Can I Find Earth's Magnetic Field Without SIRI?

Can I Find Earth's Magnetic Field Without SIRI?

Any day now there will be no one left who remembers car trips with AAA TripTiks and maps on Grandma’s knees as she helped Grandpa navigate unfamiliar roads. It’s hard for young adults to imagine a pre-GPS world. Many things – like rotary dial telephones – that become obsolete can be safely relegated to museums. Some simple tools, like the earth-magnetic-field compass deserve another look.

Outdoor adventurers who seek the untrodden path know that the possibility exists for Siri to be out of range or battery power to be drained. A simple tool like a compass uses the swirling inner core of iron and nickel that creates earth's magnetic field to guide you. It isn't dependent on Global Positioning Satellite (GPS) information which takes measurements from the sky and transmits them back to your battery-powered, cell-tower-dependent device.   

The parts of any compass are:

  • Base Plate – As the name suggests, this is a plate on which the whole compass is built.
  • Travel Arrow which points toward the direction in which you have to move.
  • Index Line is an extension of the travel arrow and it shows you where to read the bearings.
  • Rotating Bezel Dial is a circular component marked with number degrees from 0 to 360. You can twist this dial in a clockwise direction.
  • Magnetized Needle is the spinning needle inside the compass housing that always points to the magnetic north.
  • Orienting Arrow is the non-magnetic arrow used to help line up the bezel with the directions on the map.
  • Compass Housing is a clear plastic, non-magnetized casing.
  • Orienting Lines orient the bezel in alignment with the north and the south directions by the maps.

As technology has advanced scientists, geologists and engineers have been able to determine that there are differences between the magnetic poles and the poles that are the actual axes around which the earth rotates. For extreme sports where precision is required – like climbing Mount Everest - there are professional compasses which quantify more metrics; however for most outdoor adventurers magnetic north is well within their needs.


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