What are the benefits and limitations of using a magnetic compass in early navigation?
368404
well i know one benefit is that it dont require electrical power
101219
You would have to be traveling in a car at about 30 km/h because the magnetic north pole moves.  So your compass would be shaking back and forth as the magnetic north pole "wobbles" as it moves towards siberia.\n\nIf the magnetic north pole had been stationary, then your needle would point straight down.  You can confirm this by holding a bar magnet underneath your compass.
281745
Navigation with trig uses the basic principals of the patagorean theorem (a squared + b squared = c squared), sin (pronounced sine), cosin (pronounced co-sine), and tan (tangent).  If you remember the helpful hint SOH CAH TOA (pronounced so-cah-toe-uh) it will help you to remember sin = opposite over hypotenuse, cosin = adjacent over hypotenuse, and tan = opposite over adjacent.  These refer to the sides of a traingle.  Draw a right trinagle (that is a traingle with a right angle in it).  To find any one of the angles, you use what I described above (if you know the length of the sides).  You can mix the equations up and solve for any part of it that is unknown if you know the other two.  Now, back to your question...  A navigator will usually have a chart (map) with a scale on it (measurement on the paper).  With this he / she can tell the distance between any two points, thus giving the length of the side of a traingle.  If they do this from a couple of different points, it is called "triangulation".  Now they have the "triangle", they use the stuff above to figure out the angles, distances or whatever.  Finally, they use a formula of distance = rate x time (D=RT) and variations of it (T=D/R, and R=D/T).  Let's say the navigator want to know how long it will take to get from point A to point B.  They use what I've described above to measure the distance (D), and they know how fast they are traveling (with a speedometer or airspeed indicator, etc).  Now they can use T=D/R to figure out how long it will take to get there.  In "old" times, the accuracy of charts and maps was not quite up to par, so they used the "stars" as thier maps.  these were "known" quantities, with specific angles to the horiozon (which remained fixed).  The device they used was called a "sextant".  This gave them a reading of the angle.  They would also used an hourglass for time, and a specially-made board with a rope with knots in it.  As they let out the board and it hit the water, they would "time" how many knots passed through thier fingers.  This gave them "rate" (or speed).  Using what I described above, they could figure out the rest.  Hope this helped.
516822
Goring was almost right. Compasses do work there most of the time. The anomolies occur when gas is released from the buried gas hydrates, most often after an undersea landslide (very common off the Mississipi delta). The gas bubbles become electrically charged as they rise through the water and at the point where they emerge there are localised magnetic distubances which cause erratic behaviour in compasses.
93529
See, when you read a compass it does not point to true "north" it points (north) to the MAGNETIC pole which currently is in Hudson Bay. SOO if you're reading a map it will give you true north and if its a good map, magnetic north. Most people use maps that use true north. THEREFORE when you're "on the ground" and trying to find your way around and you have a map that points to Magnetic north and your map uses true north you have to take that into account. So we use declination on our compasses so that they guide us more towards true north, rather than into hudson bay. So what you will notice is that a map showing declination over the US is that people BELOW Hudson Bay use little declination because true north is basically where magnetic north is, but way out in Washington and Oregon you have to use more declination because your compass needle will be pointing more easterly that it should.....make sense?
441909
If you get an A with this work please share it with me. If you get an F , forget me.\n\n  \n  Magnetism are 2 sides (+ and -) (like in some relations). Every compass will go to the North because of magentic fields, those fileds are kind of circles like the air waves of radio or Tv.\n\n  2. Electromagentic is a toold like iron that needs electricity to work and work as a magnet, it is important a battery or other source of low voltage. Electromagentics are used to attract old cars, electromagentics are used for people who lost some things on the sand (those kind of electromagnetics are the ones with one circle in the end where the person is attracting something).\n\n 3: Electromagentic needs a switch like light, turn on and off, you let the energy flow and you get the magnetic field or you deny that flow, on the other hand the magnet is always "on", there are magnets where both sides are positive or negative, most of them are positive and negative like in electricity you need both to have electricity.\n\n 4:For instance the motor of one car, inside the motor you will see a lot of pieces and is kind of interesting because thin cables are allowing the flow of electricity, so with that in mind the motor is moving, produces energy then
219376
The earth has two magnetic poles, a north pole and a south pole.\n\nThe effect of both poles can be detected by a good compass from anywhere on earth.
466855
usually a wheel, mounted so that it can spin about an axis in any direction. When spinning, the gyroscope has special properties. Many spinning objects exhibit some of these properties; the rotation of the earth about its axis gives it the properties of a huge gyroscope. Once a gyroscope starts to spin, it will resist changes in the orientation of its spin axis. For example, a spinning top resists toppling over, thus keeping its spin axis vertical. If a torque, or twisting force, is applied to the spin axis, the axis will not turn in the direction of the torque, but will instead move in a direction perpendicular to it. This motion is called precession. The wobbling motion of a spinning top is a simple example of precession. The torque that causes the wobbling is the weight of the top acting about its tapering point. The modern gyroscope was developed in the first half of the 19th cent. by the French physicist Jean B. L. Foucault, and its first notable use was in a visual demonstration of the earth's rotation. In the second half of the 19th cent., with the invention of the electrically driven rotor, its uses multiplied. It became possible to rotate the gyroscope's wheel at desired speeds without interfering with the precession. Large gyroscopes are used in ship stabilizers to counteract rolling. The gyroscope is the nucleus of most automatic steering systems, such as those used in airplanes, missiles, and torpedoes. It is also used in the gyrocompass, a directional instrument used on ships. Unaffected by magnetic variations, its spinning axis, when brought in line with the north-south axis of the earth, provides an accurate line of reference for navigation.\n\nAlso look at...\n\nhttp://en.wikipedia.org/wiki/Gyroscope
152758
The measure magnetic fields with a magnetometer.
1100581
First there are 3 north poles. There is magnetic north which your compass will point to, There is the North Pole the earth rotates on and then there is North which would be the top of the earth as compare to the sun and its orbital plane. We can also refer to north based on the position of the galaxy and assigning one end as North and the other as south. North and south poles are used in navigation after the discovery of the compass needle always pointing north.
982565
It can't be done with an unmarked straightedge and a compass, but it can be done with a *marked* straightedge and a compass. The latter was doen by Archimedes about 200BC.
56218
Cool question. GPS (satellite) navigation is totally interesting.\n\nNow  you can buy super cheap old map CD's like Rand Macnally StreetFinder, or Microsoft"Trips and Streets" on ebay which hook up to a cheap GPS. These will run on any old laptop and you've got a navigation system for low cost.\n\nNow you can also store a map on CD pretty easily and use it with an inexpensive GPS unit. There are lots of shareware programs to do this. Gartrip is the easiest to use in my experience.
94918
This sytem was in place before GPS it was called Loran it was not as accurate. Really good thinking though Barbie, you are going places. Let me add that a system is in place now to locate cell phones in exactly the way you propose for emergency situations. However I believe in the future cell phones will incorporate conventional gps, as in an eperb and also for the user as location info.
944389
I researched this as a geology student 20 years ago and has interested me since then.  By researching cores of basalt, they have a pretty good idea what the magnetic field does when it starts to shift but it is somewhat random and slow.  I remember that typically, before the switch in polarization, the poles starts to migrate in a spiral as it is doing now.  It has been an extra long time since the last switch so it is due.  I suspect that it is about to switch (within the next thousand years or so) but no one can say for certain in my opinion.  Apparently there is a period of time (100 years or so) when the field is next to zero in strength.  I saw a show on it recently that demonstrated they have learned a lot since I studied it in school.
416671
This is a wonderful activity to develop your exploring skills. I am providing some great website resources that I fully endorse. For easy cache sites a simple inexpensive handheld GPS is okay. I prefer a handheld unit that has mapping capabilities. There are more expensive handheld units that even have color screens, barometric altitude, and digital compass. My pick of choice is the Magellan Meridian-Color USA. There are sites from as near as your back yard to clear across the country. This is an activity that the whole family can get involved in for a small initial investment of one or two GPS units and a pair of two-way radios.
1131218
Most maps intended for navigation or hiking have magnetic deviation printed on them. Here is an online deviation map for people lining up satellite dish antennae.
975356
The invention of the compass changed the world. With this revolutionary device, sailors were able to navigate more accurately. Oceans were crossed, and new lands were discovered. Even with today's technological innovations, travelers still depend on compasses to lead them in the right direction.\n\nWho Invented the Compass?\n\nLegend has it that the original compass can be traced back to the ancient Chinese. The first known use of a compass occurred in the fourth century B.C. It was used in Feng Shui, the Taoist method of environment organization. Chinese fortunetellers used lodestones, a mineral composed of an iron oxide that aligns itself in a north-south direction, to construct their fortune telling boards. The Chinese eventually noticed that the lodestones were consistent at pointing out actual directions, leading to the first compasses. They designed the compass on a square slab with markings for the cardinal points and the constellations. The pointing needle was a lodestone spoon-shaped device, with a handle that would always point south.\n\nThe first written mention of the compass was by a Chinese mathematician in about 1050. Shen Kua wrote about the use of a navigational instrument with a magnetized iron needle. The first recorded instance of European compass use occurred in 1190. Very little was understood, though, about how the compass worked. Superstitions abounded, including sea captains believing that if the crew ate onions it would impact the device. In the centuries that follow, historical references of compass use increases. Arabian and Viking explorers are described using the device to navigate across many miles of water in the early and mid-1200s.