Ynan

Based from your explanation (Thank you for it, by the way), the shape of the iron fillings has to do something with the gaps. What would happen if the filings are turned into spheres? Can somebody do the experiment? I noticed in the video that the gaps aren't real gaps in the magnetic field (3D), they are simply brought about by the temporary friction of the structures (chains of iron filings) to the fluid. Once the resistance is overcome, the structures actually move straight towards that magnet, until the magnet becomes saturated with iron so that its magnetic field strength becomes shielded to further pull the remaining (chains) towards it. This absence (or minimal pull) of the downward pull of the magnet due to shielding is what keeps the remaining chains suspended in their places, thus giving the illusion that there are gaps in the magnetic field.

yes I did, and there is one thing that I can't seem to understand on the explanation. Magnetic fields are supposed to be continuous, (they are strongest from the source, becoming weaker through distance) hence, the first assumption in the explanation that "magnetic field lines" are uniformly distributed is already a divergence from the existing concept of what a magnetic field is due to the conception that there are magnetic field "lines". Are there really magnetic field lines? Then the explanation moves on to explain that gaps are partly due to the repulsions between the induced magnets (iron filings). My contention here is that, are those repulsions so strong that they could cause such large gaps? If they do, why aren't the iron filling within each line(shell) do not repel each other seeing that there are some of them that are perfectly aligned (on each side). My third contention is that if minimization of energy is the main reason why the iron filing tend to converge with each other to form lines and gaps, would it not more energy efficient for the magnet and the iron fillings to want to distribute themselves uniformly, tightly packed, attached to the magnet?

About the explanation of why the layers form: If each iron feeling turns into N-S magnet, then we cannot expect to form a layer with more than one iron feeling perfectly parallel to each other within the same layer - can we check on this? Problems about the explanation: How can we form an entire 3D shell if each iron filling turns into a N-S magnet, there would be strong repulsion within each shell that would destroy it. The only way to for a complete shell to form is to align all iron fillings in such a way that the N-end touches the S-end top and bottom., and side by side like how bricks are stocked on top each other. However, there is another problem with this, if the repulsions can be minimized this way, then how can we account for the huge distances between layers? Lastly, if a shell can form, using the arrangement shown in my picture, then notice that another shell that is completely attached to first shell can form on top and the bottom, thus we would expect a one big blob of iron around the magnet and not layers of shells like in onions. Can someone check my reasoning here?