Not so Trusty Compass

[+Waterboy]

Back on July 7, 2001, we were looking for our forth cache, named Boston Cache, located in Harriman State Park, New York. The cache is located near an old iron mine named Boston Mine. On arriving in the general cache area I pulled out our compass and observed it was pointing exactly toward the mine entrance, which was East.

 

Having a compass point other than north was not a surprise. My first compass lessons, given by my mother, included this. This lesson was in the early 1950s, and was also in Harriman Park. About 1955, as a Tenderfoot Boy Scout, I received the same lesson by a mine in or near Harriman Park. Now a resident of eastern Pennsylvania, and a regular hiker, I have seen compasses do many strange things in my present home state. Of course this phenomenon has also been observed in weird New Jersey. The common link being that there are many large iron containing deposits in these hills.

 

In these forums I have not seen any write ups of weird compass problems. If anything, I have read how great the "trusty" compass is. Does anyone have any comments?

 

Additional questions:

1. Any compass stories from Northeast Canada?

2. Any comments/stories on the Boys Scout method of find north using sun and (analog) wrist watch.

[+Mr. Snazz]

I went caching with a friend once, in his car. We were going to place a cache, and were waiting outside the army surplus store (they were late opening that morning) to get an ammo box. While we waited, we were trying to determine which direction to go and where exactly we were on the city map (long story). My compass was pointing totally the wrong direction.

 

My friend had recently installed the biggest speaker system known to man.

 

[+megansdad]

Which way will a compass point if you where standing on the north pole?

And would it demagnetize it?

[+Waterboy]

quote:

---

Originally posted by megansdad:

Which way will a compass point if you where standing on the north pole?

And would it demagnetize it?

---

 

At the north pole all directions are south, but a simple answer of south, although correct, is not adequate. The compass would point to a location sometimes referred to as the "Magnetic North Pole". This magnetic north pole is not distinct point, it varies. Its general location is in Northern Canada.

 

The compass would not be demagnetized, and would only act weird near the magnetic pole.

[jdege]

If you are standing at the North (Magnetic) Pole, with a handheld compass you bought pretty much anywhere in the world, it won't point, it will stick.

 

The magnet in the compass lines up with the lines of magnetic force, and those do not always run parallel to the surface of the earth. They run into the ground at an angle, and the closer to the pole the steeper the angle.

 

Now on a free-floating ball compass, this doesn't matter. But on the more common pointer/pivot compasses, one end or the other is counterweighted, to keep the pointer reasonably close to level.

 

It's not something that has to be very precise - your compass isn't going to be out of balance because you head north a couple of hundred miles. But if you change lattitude by 45 degrees or more, you can expect that the pointer of your compass will be sufficiently out-of-balance that you'll have to hold the compass noticably off horizontal in order for the pointer to swing free.

 

(When I headed off for college, I put my old Silva Boy Scout compass in a metal cookie tin, along with a bunch of other assorted junk that I didn't need and didn't want to throw away. When I opened the tin, 15 years later, the compass had reversed polarity, the southern end of the pointer pointed towards the North - if I held the compass about 30 degress off of horizontal so that the pointer would swing free. I put the compass in a dresser drawer, and forgot about it, and a couple of years later it worked normally again. It's a puzzlement

[jdege]

If you are standing at the North (Magnetic) Pole, with a handheld compass you bought pretty much anywhere in the world, it won't point, it will stick.

 

The magnet in the compass lines up with the lines of magnetic force, and those do not always run parallel to the surface of the earth. They run into the ground at an angle, and the closer to the pole the steeper the angle.

 

Now on a free-floating ball compass, this doesn't matter. But on the more common pointer/pivot compasses, one end or the other is counterweighted, to keep the pointer reasonably close to level.

 

It's not something that has to be very precise - your compass isn't going to be out of balance because you head north a couple of hundred miles. But if you change lattitude by 45 degrees or more, you can expect that the pointer of your compass will be sufficiently out-of-balance that you'll have to hold the compass noticably off horizontal in order for the pointer to swing free.

 

(When I headed off for college, I put my old Silva Boy Scout compass in a metal cookie tin, along with a bunch of other assorted junk that I didn't need and didn't want to throw away. When I opened the tin, 15 years later, the compass had reversed polarity, the southern end of the pointer pointed towards the North - if I held the compass about 30 degress off of horizontal so that the pointer would swing free. I put the compass in a dresser drawer, and forgot about it, and a couple of years later it worked normally again. It's a puzzlement

[+unclerojelio]

I held my compass next to my vista to compare the two. For some strange reason the needle always pointed toward the vista. I guess if I ever lose my GPS I can use my compass to find it.

 

... Two roads diverged in a wood, and I--

I took the one less traveled by, ...

 

unclerojelio

[+unclerojelio]

I held my compass next to my vista to compare the two. For some strange reason the needle always pointed toward the vista. I guess if I ever lose my GPS I can use my compass to find it.

 

... Two roads diverged in a wood, and I--

I took the one less traveled by, ...

 

unclerojelio

[+Icenians]

quote:

---

Originally posted by Mr. Snazz:

I went caching with a friend once, in his car. We were going to place a cache, and were waiting outside the army surplus store (they were late opening that morning) to get an ammo box. While we waited, we were trying to determine which direction to go and where exactly we were on the city map (long story). My compass was pointing totally the wrong direction.

 

My friend had recently installed the biggest speaker system known to man.

 

http://geo.mrsnazz.com/snazzsig.jpg

---

 

Was the car made of plastic? A compass wont work well in a car with or without a speaker system.

[+megansdad]

icenians,The Cars speakers acted like the magnetic north pole.

[+megansdad]

icenians,The Cars speakers acted like the magnetic north pole.

[+Alan2]

quote:

---

Originally posted by Mr. Snazz:

I went caching with a friend once, in his car.... My compass was pointing totally the wrong direction.

---

 

Bang the compass on the dash two or three times. It might not help but you'll feel better afterwards.

 

Alan

[+Alan2]

quote:

---

Originally posted by Mr. Snazz:

I went caching with a friend once, in his car.... My compass was pointing totally the wrong direction.

---

 

Bang the compass on the dash two or three times. It might not help but you'll feel better afterwards.

 

Alan