# The Naked Scientists Forum

### Author Topic: Would this compass design continue to move about?  (Read 944 times)

#### Thebox

• Neilep Level Member
• Posts: 3139
• Thanked: 42 times
##### Would this compass design continue to move about?
« on: 21/12/2015 18:29:13 »

#### alancalverd

• Global Moderator
• Neilep Level Member
• Posts: 4489
• Thanked: 137 times
• life is too short to drink instant coffee
##### Re: Would this compass design continue to move about?
« Reply #1 on: 22/12/2015 00:13:52 »
If by "move about" you are referring to turning and acceleration errors, the answer is yes. These phenomena are due to the center of gravity of the needle or ball being below the suspension point, and there being a finite dip at most latitudes.

#### evan_au

• Neilep Level Member
• Posts: 3932
• Thanked: 224 times
##### Re: Would this compass design continue to move about?
« Reply #2 on: 22/12/2015 09:28:02 »
I'm not quite sure what you mean in the diagram by having two north poles and two south poles?

If this is meant to represent two regular compass needles mounted at right angles, then the they will orient themselves so that the North Magnetic pole of the Earth lines up half way between the two pointers marked "n".

It will take just as long for these double pointers to stop moving about as for a regular compass.

#### Colin2B

• Global Moderator
• Neilep Level Member
• Posts: 1760
• Thanked: 115 times
##### Re: Would this compass design continue to move about?
« Reply #3 on: 22/12/2015 11:06:45 »
Think vectors and resultant forces in your diagram and you will understand what Alan and Evan are saying.

#### Thebox

• Neilep Level Member
• Posts: 3139
• Thanked: 42 times
##### Re: Would this compass design continue to move about?
« Reply #4 on: 23/12/2015 19:42:16 »
I'm not quite sure what you mean in the diagram by having two north poles and two south poles?

If this is meant to represent two regular compass needles mounted at right angles, then the they will orient themselves so that the North Magnetic pole of the Earth lines up half way between the two pointers marked "n".

It will take just as long for these double pointers to stop moving about as for a regular compass.

Yes , two compass needles mounted at right angles, magnetic north and south, I suspected they would align both north points at a 45 degrees angle to north.

#### The Naked Scientists Forum

##### Re: Would this compass design continue to move about?
« Reply #4 on: 23/12/2015 19:42:16 »