Like many kids, my children love Magna-Tiles. For those not familiar with them, they are transparent plastic squares and triangles with magnets embedded around the edges. When two Magna-Tiles are placed edge-to-edge, the magnets stick together, allowing you to build structures just placing them next each other.
What’s really great about them is that the magnetic attraction is perfect for beginning builders. Because pieces naturally stick together, you don’t need much precision to place pieces correctly (as opposed to Legos, which need to be perfectly aligned), and they can defy gravity in a way that blocks cannot.
I’m one of those people who always wants to understand how things work, and there is something about the Magna-Tiles that bothers me – they never seem to repel each other when you build with them. Magnets are polarized, with a “North” side and a “South” side. If you pick up two regular magnets, the north and south sides will stick together, but you can’t connect two Norths or two Souths. I see this most often with my kids’ wooden train sets, where the cars are connected with magnets. To connect two cars, they have to be oriented with the North/South polarity matching. If one is facing the wrong way, they push away from each other rather than sticking.
Magna-Tiles don’t seem to suffer from this problem. I can rotate the pieces in any orientation or flip them over, and they always stick. Shouldn’t there be “correct” and “incorrect” alignment? If they stick together one way, which means the North/South poles are matched correctly, shouldn’t flipping the piece around cause it to be incorrect?
I tried googling this and have found some other people who are as puzzled as I am but no clear explanation.
The other day, it finally dawned on me how they must work, so I figured I would share for other curious parents.
The first part of the secret to the Magna-Tiles is that the North-South direction is not along the edges, but rather in the Z-axis. If you lay a Magna-Tile flat, think of the four edges as the four directions. The poles of the magnets, however, are in the up and down direction, not out along one of the sides, as I had originally assumed.
The second part of the secret is that each Magna-Tile has two magnets on a side, and these magnets are oriented in opposite directions. So, if the one on the left has North pointing up, the one on the right has North pointing down. This continues around all four edges of the Magna-Tiles, with each magnet having the opposite North/South alignment of the ones on either side.
I’ve tried to illustrate with this crude diagram. As you can tell, my background is in software engineering, not graphic design:
Because of the alternating pattern with two magnets per edge, there is no way to place two Magna-Tiles next to each other such that the magnets are facing the opposite direction. Regardless of whether you rotate it or flip it around, you always have the configuration of magnets and polarity.
And, most crucially, if you place two tiles next to each other, the adjacent magnets have poles facing opposite directions in the Z-axis, which means they will stick together. In other words, the left tile’s north side touches the right tile’s south side, and vice versa. And so they stick.
The only way to make two Magna-Tiles repel each other is to place them misaligned, with the top half of one touching the bottom half of the other one. Then you will find the magnets repelling each other. However, since this is not a normal way to attach Magna-Tiles when building a structure, it doesn’t happen much in practice.
I hope this explanation makes sense. If not, try playing around with some Magna-Tiles while keeping in mind that the North-South is facing up and down on the Z-axis, not the X-Y axis of the Magna-Tile itself, and you will see what I mean.