Does The Direction Of Magnetic Force Change? 11 Crucial Facts

Does the direction of magnetic force change? the answer to this is as we discuss further. We can discover crucial details about a part of our world that would not otherwise be available by connecting the observable changes to underlying processes.

Reversals, which happen at random periods a few times every million years, have historically been linked to the quickest changes in the Earth’s magnetic field.

But unlike any of the data linked to real reversals, we found field changes that are far faster and more recent.

Does the direction of magnetic field change?

The magnetic force modifies the direction of the particle’s movement but not its speed or kinetic energy. Magnetic force on a wire, Magnetic deflection of electrons in a cathode-ray tube, Magnetic force on a proton.

does the direction of magnetic force change
“Earth’s Magnetic Field” Image Credits: Wikimedia

In regions where the magnetic field was diminishing, Davies and Constable found that the magnetic field may shift by as much as 10 degrees every year. This rate is around 10 times quicker than what prior models predicted and nearly 100 times faster than changes observed in contemporary measurements.

The models demonstrated that the magnetic field direction would abruptly change as parts of the molten core flipped direction. The researchers’ observations of rapid directional changes at low latitudes were consistent with the fact that this core reversal was more frequent in regions near to the equator.

According to the study’s authors, this fresh evidence that low latitudes undergo changes the fastest recommends that scientists should focus their efforts there in the future.

Why does the direction of magnetic force change?

Electromagnetic forces connect electric currents with fluid flow. Additionally, the makeup of the core is probably not uniform. Eddy currents can be produced via electromagnetic induction in addition to the fluid flow carrying charge. Without fairly powerful computers, it is impossible to solve the equations characterizing this extremely complicated system.

The substance which creates the Earth’s outer core is both a liquid and a conductor of electricity. Thermal convection currents give out fluid flow.

The Earth’s magnetic field is “chaotic,” according to numerical simulations, and it frequently changes its polarity and structure. Due to this intricacy, it is possible for the magnetic field to vary without the electric currents’ directions necessarily changing anywhere they are flowing.

A relatively slight change in flow could result in a significant shift (or even a reversal) in the magnetic field because the system is “chaotic.” Despite being simulations, the computer models have been very successful at recreating the secular variation of the magnetic field that we can measure at the Earth’s surface.

“Magnetic fields that change” Image Credits: Wikimedia

How much does the direction of magnetic field change?

The planet’s liquid core produces the magnetic field, with the iron’s whirling movements producing a field that stretches into space. By diverting the solar wind—a stream of charged particles flowing from the sun—it serves as a barrier shielding Earth from the sun’s harmful radiation and aids in maintaining our atmosphere.

Scientists have found that the earth’s magnetic field may shift directions about ten times more quickly than previously assumed. Researchers were able to demonstrate how the field has altered over time by simulating the last 100,000 years of activity. Findings indicated that abrupt changes in direction frequently occur during times of reversal, when the field is locally weak.

The magnetic field is continually shifting because of the liquid core’s movements. The magnetic north and south poles switch positions when it becomes significantly weaker. These eras have been connected to extinctions and are accompanied by elevated radiation. Understanding how, when, and why changes occur is difficult since they occur over incredibly long stretches of time.

“The amount of magnetic field that changes” Image Credits: Wikimedia

How often and when does the direction of magnetic field change?

Since it has a North pole and a South pole, the magnetic field primarily resembles a dipole. A compass needle will be directly down or up in these locations, accordingly. It is frequently said to resemble the field of a bar magnet, such as one seen on a refrigerator. The Earth’s field, which differs greatly from that of a bar magnet, exhibits significant small-scale fluctuation.

Using a magnetic compass will reveal that the Earth has a magnetic field. It is mostly produced in the planet’s extremely hot molten core and has likely existed for the majority of the planet’s history.

It’s interesting to note that sometimes the magnetic field just experiences a “excursion” rather than a reversal.

Here, it experiences a significant loss in overall strength, or the force that propels the compass needle. The field does not reverse during an force; rather, it later regenerates with the same polarity in action, so North pole remains North and South pole remains South.

What changes the magnetic field direction?

Cretaceous Period is usually the time periods which has reversals at every other points in history of earth. Reversals are neither predictable nor, by any means, cyclical. Therefore, we are limited to discussing the average reversal interval.

The Earth’s magnetic field has experienced many polarity reversals throughout its history. This is seen in the magnetic patterns of volcanic rocks, particularly those dug up from ocean floors. Averaging 4 or 5 reversals every million years over the past 10 million years.

For instance, it appears from the mathematical simulations that a complete reversal may take between one and several thousand years to complete. Although sluggish on a human time scale, this is rapid by geological standards.

As mentioned above, there isn’t much information available from geological measurements concerning how the magnetic field changes as it reverses.

 It’s also possible that over time, the poles will “wander” from their present locations towards and across the equator. Anywhere on Earth, the field’s overall power may be no stronger than a tenth of what it is right now.

Right-hand principle

The right-hand rule is simply a convenient technique for physicists to recall the expected directions of motion; it is based on the underlying physics that connects magnetic fields and the forces they exert on moving charges.

To remember the direction of magnetic forces, physicists applied a hand code known as the right-hand rule. Next, point your middle finger such that it is parallel to your index and thumb.

There are times when a physicist will unintentionally use their left hand, leading them to forecast that the magnetic force will point in the wrong direction.

“Magnetic field by the right hand rule” Image Credits : Wikimedia

Magnetic Field Change Examples

Current In Wire

Since we already know that current is nothing more than moving charges, when a current is flowing through a wire, it will only be impacted by a magnetic field in the same way as a single moving charge.

The movement of positive charges via a wire is what we mean when we talk about conventional current in a wire

The thumb points in the positive xxx direction, the first finger in the positive yyy direction, and the middle finger in the positive zzz direction. This is known as the right-hand rule.

Magnetic Field Caused By Current In Wire

A straight wire’s magnetic field, created by a current flowing through it, forms a ring around the wire. You can locate it by curling your fingers and pointing your right thumb in the direction of the wire’s current. The magnetic field surrounding the wire will cause your fingers to curl in the same direction.

Magnetic fields are not just influenced by moving charges; they can also be produced by moving charges. A second right-hand rule can be used to determine the magnetic field produced by moving charges.

It turns out that if you already know the direction of the magnetic field, you can apply the opposite of this method to determine the direction of the current in a wire.

This time, point your thumb in the magnetic field’s direction, and curl your fingers like you did before. This time, you can determine the direction of the current that generates the magnetic field by looking at the circular motion of your fingers.

The Magnetic Field In MRI

A powerful fixed magnetic field is used to align the individual protons connected to water molecules throughout the body during an MRI, or magnetic resonance imaging, procedure. This alignment procedure is the first stage of a measurement that makes use of tiny proton deviations from the field to map out the structure and density of distinct patient body sections.

In order to perform a basic MRI, a strong magnetic field must be generated along the body’s axis. This is the reason why one design of the gadget features a huge electromagnet coil that encircles the patient’s torso.

The current that spirals around the patient creates a magnetic field that points straight down the patient’s body, as we have learnt from the right-hand rule.


Like we have seen from the above discussion, we know that the magnetic field changes according to the factors. There are so many tings which contributes to the change in the magnetic field. Earth’s magnetic field is the natural occurring and it may very depending upon the factors that affects the action.

Keerthana Srikumar

Hi...I am Keerthana Srikumar, currently pursuing Ph.D. in Physics and my area of specialization is nano-science. I completed my Bachelor's and Master's from Stella Maris College and Loyola College respectively. I have a keen interest in exploring my research skills and also have the ability to explain Physics topics in a simpler manner. Apart from academics I love to spend my time in music and reading books. Let's connect through LinkedIn-

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