# Which pole is up?

#### HarryA

Jan 22, 2017
82
While working with unipolar hall-effect senors I checked which face of the bar magnet was the south polar with a compass. The sensor responds to the south magnet but I found that the face that triggered the sensor was the one that the north pointing compass needle pointed to. Looking on wikipedia I found:

"The North geomagnetic pole actually represents the South pole of the Earth's magnetic field, and conversely the South geomagnetic pole corresponds to the north pole of Earth's magnetic field (because opposite magnetic poles attract and the north end of a magnet, like a compass needle, points toward the Earth's South magnetic field, i.e., the North geomagnetic pole near the Geographic North Pole)."

So if the North pole is down there then does that mean Australia is on top and we are on the bottom?

#### Martaine2005

May 12, 2015
4,960
does that mean Australia is on top and we are on the bottom?
Lol, the earth spins at 14,000 Mph.
So I’d guess that we have a 50/50 shot every 7,000 Mph.
I thought Hall effect sensors automatically reversed polarity (poles).

Martin

#### Martaine2005

May 12, 2015
4,960
That link wanted to reverse me!.

Marrtin

May 12, 2015
4,960

#### Kiwi

Jan 28, 2013
474
Yes, and New Zealand is even more on top!

Moderator
Nov 17, 2011
13,769

#### TCSC47

Mar 7, 2016
148
There is sometimes confusion for students starting to discuss magnets. The north pole of a permanent magnet is better termed the North seeking pole. So in reality what we normally call is the north pole of the magnet is the same polarity as the Earth's South Pole. I seem to remember an exam question on this some where. Usual exam cunning stunts.

#### TCSC47

Mar 7, 2016
148
So if the North pole is down there then does that mean Australia is on top and we are on the bottom?
My Ozzy friends would agree with this, I'm sure!

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