Earth's Magnetic Field - An Explanation

This video is in response to the numerous errors I have seen online regarding the earth's magnetic field. I hope you take a few minutes and can learn something interesting from this video.

Here are links to the university and governmental websites that have this information wrong:

Most of the images came from Wikipedia, and were thus in the public domain. All others are copyright of their respective owners and used under fair use for educational purposes. If you would like to learn more about this topic, check out some of these great sites:

[typealt]

Some of the comments claim that the North, red side of the needle isn't a magnetic north pole, but rather a magnetic south pole, pointing towards the top of our world.


So, place a bar magnet towards a compass. If the red, magnetic north pole of the compass gets attracted to the south pole of your bar magnet, then I am in fact correct. Go ahead and try it at home! It'll be a fun science lesson.

[yeetusdeletus]

Alien: So what's so special about living here?
Human: The north pole is actually the south pole.

[KTFG]

It is a big deal!   Great video.
I discovered this while building a polarity detector.
The North pole of a magnet points to the Geographic North which means Geo North is Magnetic South.  Think of it like this "North Pole of Magnet is short for North Pointing Pole. Its confusing if you don't know.
Much like the flow of current, Negative to Positive (Electron Flow) or Positive to Negative (Conventional Flow). Most colleges and text teach this wrong.  Even some tests have it wrong.

[deionford]

instead of saying the north pole is really the south pole why cant we just say the red point on a compass is the positive end of the compass pointing north to the negative point of the earth.

[udith]

What ever it is, it's just for convention. So it is not that wrong. Also the same applies for electricity, we take the direction opposite to the flow of electrons as the direction of current

[matthiaswille]

Whilst the video correctly points out that the Earth's magnet south pole is near the geographic north (for simplicity reasons I will not go into the merits of magnetic field variation), it has two mistakes which rather add up to the confusion:

In the image shown in the video sequence in minute 3:33, the narrator explains the correct polarisation of the Earth's magnetic field, but the image TEXT shows quite the opposite. The same applies to the video sequence in minute 4:31, where again the polarisation (centre magnet) is correctly showing the RED North pole pointing to geographic South, whilst the respective pole text is Sg AND Sm for for the geographic South and Nm AND Ng for the geographic North respectively. It should however show Sg AND Nm (geographic South) and Ng AND Sm (geographic North).

The other thing the video misses to clarify is the fact that this is merely by definition: it seems the majority of scientists define the RED North pole of the magnet by its polarisation and NOT (as often explained) by its polarisation SEEKING (which is quite the opposite).

To make it more clear: the magnet's RED North pole is North by polarisation, but South SEEKING. That is why the red part of a compass needle is pointing to the magnetic South pole of the Earth (at its geographic North), because its polarisation is North and it seeks South.

[ChristianSmallgolf]

that is unless the magnet in all compasses has been put in upside down to best reflect N goes to North

[DavidPopeDog]

The Earth's magnetic field probably changes because the sun induces a magnetic field direction North and South onto the Earth's magnetic core.  Like a compass in water, the Earth's core rotates in a liquid core that surrounds it, and comes to rest in the new alignment relatively quickly.  Now, as for the sun, I believe the reason why it changes magnetic polarity has to do with electrons being consumed at its core, in some kind of cycle that has to do with fusion which causes the magnetic sunspots on its surface to go to zero then come back with opposite N & S.  Since it takes about 1.2 million years for a photon at the core to reach the surface of the sun, it is not too far fetched to guess that a fairly short cycle in the sun's core could result in a periodic event at the sun's surface... say, every 10, 000 years... If the sunspots come back full force on the sun, and they have reversed polarity compared to pre-1990's, then this might be a correct guess.

[Marcios]

A recent scientific publication on the "Origin of Geomagnetism" shows "A New Hypothesis to Fully Justify the Generation, Maintenance and Behavior of Geomagnetism". Just search.

[gensyed]

Or could it be that the North indicating needle is actually a South pole?- wrongly understood in ancient times.

[michaelgregg]

To correct a little more misinformation being spread here (and on other sites): the image of magnetic field lines that appears at 1:53 into the video is incorrect in one minor and important way. The field line in the center joining the two N poles of the magnets should not be there; all the field lines, even at the center, will curve outwards, avoiding the like pole of the other magnet, and seeking a south pole somewhere. This is a fairly common misrepresentation in the depiction of magnetic field lines.

[mrsloppyryan]

I think your concept is wrong. I think the compass's "N" is just there to show where north is, and not that a "north" magnet in the palm of your hand is attracted to the Northern magnetic field of Earth.

aka, designers of compass's put a south magnetic field where it says "N" so that someone can determine where North is. It's just how a compass is designed as to not confuse the hell out of the people that use it.

[meagain]

Ah how do you know that a common compass doesn't have a south pole magnet painted red to show the attraction to the earths north
magnetic field?

[chazchavara]

YouTube is such a good place for learning

[DonaldSleightholme]

i found out that magnets don’t work when heated. could you explain how the earths molten core generates a magnetic field? 🤔 thanks

[callahans]

The magnetic N pole has the negative polarity. I think that's your point, but to diagram the magnetic poles different from what we're used to seeing would be too confusing. Better to label -/+ to reflect the polarity.

[MrFree]

What determines the North and the South Pole of a magnet?
If you set the North Pole of a magnet close to the North Needle of a compass, do they attract or they repel each other?

[sravankumarjr]

i mean you've given correct information but finally you've taken the wrong picture of Earth

[gargidas]

Our Earth acts like a huge bar magnet, which is why, it has north&south poles, The Magnetic field is though to be produced by movement in the liquid outer core. The molten metal carries an electrical charge, which generates an Electromagnetic field as it swirls around.

[tylercorrell]

Magnets themselves do not have north and south poles. They have positive and negative sides. Is there something I'm missing here? I understand that the earth is labeled with poles for cardinal uses.