Earth’s magnetic field. Compass and magnetic poles

What is the Earth's magnetic field, how is it generated and how does it help us?

The online Earth’s magnetic field simulations on this page explain the basics of the magnetic field and how the compass works.

The Earth’s magnetic field is a fundamental feature of our planet that plays a crucial role in protecting life and guiding navigation. This magnetic field, also known as the magnetosphere, is generated by the Earth’s outer core, composed mostly of liquid iron and nickel.

The main mechanism for the generation of the magnetic field is believed to be the convection of molten material in the Earth’s outer core. The difference in rotation between the solid inner core and the liquid outer core, together with heat transfer within the core, creates electric currents that in turn cause the magnetic field.

The Earth’s magnetic field has a complex structure, although it resembles a magnetic dipole, i.e., it has a magnetic north pole and a magnetic south pole. However, the axis of the magnetic dipole does not coincide exactly with the Earth’s axis of rotation, resulting in an inclination of the magnetic field relative to the equatorial plane. This means that the magnetic compass does not point exactly to geographic north, but is deflected depending on location.

The Earth’s magnetosphere extends from the core to outer space, protecting our planet from the charged particles of the solar wind. These particles, mainly electrons and protons, are emitted by the Sun and are electrically charged. When they interact with the Earth’s magnetic field, they are deflected and channeled around the Earth in the form of Van Allen radiation currents, creating a kind of protective shield. The particles, when deflected towards the polar regions, produce the northern and southern auroras, creating an impressive natural spectacle.

In addition to its protective function, the Earth’s magnetic field has a significant impact on navigation. Magnetic compasses use the magnetic field for orientation, which has been fundamental to maritime navigation throughout history.

In short, our online Earth’s magnetic field simulations show interactively how the magnetic field acts and how the compass takes advantage of it to point north. Don’t miss them!

Magnet and compass

Ever wonder how a compass works to pinpoint the Arctic? Explore the interactions between a compass and a bar magnet, then add the earth and find the surprising answer! Vary the strength of the magnet, and see how things change both inside and out. Use the field meter to measure the changes in the magnetic field.


Screen too narrow

This Java simulation cannot run on this device because it has a screen that is too narrow. We recommend that, for a better user experience, you run it on a device with a wider screen.

Narrow screen

Although this Java simulation can be run on your device, we recommend that for the better user experience, you run it on a device with a wider screen.

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Magnetic field of a bar I

The space where the magnetic force of the magnet acts is called the magnetic field. This animation shows what the magnetic field around a magnetized bar looks like. The direction of the magnetic field is determined in the direction indicated by the N pole of the magnetic needle placed at that point.
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Magnetic field of a bar II

In this simulation you can see the magnetic field around a bar indicated by arrows or compasses..
Click here to start the simulation

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