Green Magnetic Viewing Film 4x6 | Cool Magnets Science Kit | Magnetic Field Detector & Visual Aid for Physics Education | Ideal for Research & Magnetism Demonstrations

Not useful for daily things, but great for science experiments and entertainment. Probably the most useful thing about it is that it is basically 'x-ray vision' for the eddy current experiment where you drop a high-power cylinder magnet down an aluminum or copper tube and it drops very slowly. With this, you can 'see' the magnet through the tube as it falls. It's also fun to investigate refrigerator magnets and multi-magnet cubes, etc. With this little sheet, I accidentally discovered that putting my rare-earth block magnet on my fridge magnet made an obvious area where the NdFeB permanently overrode the poor little fridge magnet's field forever! :O It didn't stand a chance. "What can ferrite do against such reckless Teslas?" --fridge magnet, 2019-2019 Update: 2022 and mine still works great, although I haven't used it much. Surprised to see people saying they only work once. Maybe if you pinch the surface between two magnets, or scratch the back, you'll pop the little fluid areas and ruin them? Any way I've kept mine in its paperboard envelope and it seems safe in there.

It works, can identify poles of a magnet and identify hidden magnets, but requires a fairly strong magnet to make it work. It came out of package a nice green sheet, but as soon as you use it gets dark streaks all over. Still works, but not quite as magical as I was hoping. I was hoping to use it for wheel bearings with magnets in the race (for hall effect sensors), but I do not think it would be able to identify those very well (too weak of magnets).

These sheets are very sensitive, although you do need to use them in a well-lit environment, as the images are inherently pretty dark. Also the film will leave ghost images behind indefinitely after you remove the magnet, so you might want to periodically degauss it by wiping it with a large refrigerator magnet that can hit the entire film in one pass. Sort of like erasing one of those old Magna Doodles. While it's certainly fun to just look at magnets, especially some of the complex ones that use alternating magnetic poles to have magnets that "turn off" by twisting 180 degrees so the magnetic fields cancel, etc. It's also handy for precisely locating magnets that are embedded inside objects, like the magnet in my laptop that holds the lid shut, or pinpointing exactly where the magnets are on cabinet doors so I know where to put a pad of felt to muffle the slam, etc.

We bought 2 of these as Wheel Bearing Check Tools to make sure any of the North/South Magnetic poles on an embedded Wheel Bearing that's also the Speed Sensor ring for an ABS system are okay from packaging and shipping damage- Once you place the Film on top of one of these bearings, the Magnetic sections in the seal just jump right out visibly, and you can spot if any of the tiny magnetic poles are damaged or are all okay before you start pressing the bearing into a hub assembly. Wish we'd known about these very inexpensive tools years earlier, since ABS type speed reading bearing systems only need a single magnet pole damaged to store a Trouble Light or warning light on your dash. Without the Film to show the magnetic poles, the seals look fine to the naked eye and you'd never know a bearing might have slight damage to its seal before you installed it.

Worked perfectly for detecting the magnetic fields in my new vehicle hub assembly! Also, fun to use on magnets and stuff. It's a very thin piece of material without and borders, but it works!

I bought the following related items together, so I'm putting the reviews together as well for your convenience. A) < Magnetic Field Demonstrator, Student, Value Pack > > 1 star > Pro - cheap. > Con - filings too big & heavy to align with or indicate the flux lines, so you just get "indicators" that clumps together without revealing much insights. B) < CMS Magnetics® 4" x 6" Green Magnetic Field Viewing Film, Fun! > > 3 stars > Pro - a) it really does look very cool, & weird, & psychedelic; & b) shows magnetic strength. > Con - a) but it gives you little bang for the bucks (when including shipping); b) it doesn't show flux lines; c) thin so may be damaged if not careful. C) < American Educational Steric Demonstrator, For Magnetic Line of Force > > 2 stars > Pro - it sort of works, showing the magnetic flux lines. > Con - a) but it's overpriced for its quality; b) flimsily made with thin brittle plastic pieces glued together as if toddlers; c) pointers don't rotate well and are spaced too far, giving very low resolution; d) awkward to handle, & not designed well. D) < Dowling Magnets Mysterious Magnet Tube > > 4 stars > Pro - a) reasonably priced; & b) works surprisingly well showing the flux field. > Con - a) not as good as < 3B Scientific Three Dimensional Magnetic Field Lines Device, 140mm x 140mm x 120mm Size, 21mm Hole Diameter > ($174 as of 10/18/13), but doesn't cost as much either; b) without fluid to help counter gravity (like the expensive one above), flux lines droop. >>Conclusions: 1) For neat magnetic visual effects, get (B) of above; though methought overpriced, but still affordable. 2) For demonstrating magnetic flux lines, get (D) of above for its good value & say ~80% demonstrative effectiveness; unless you can afford the high quality alternative mentioned above. 3) Forget (A) & (C).

The product works as expected. I used them to visualize the magnetic field produced by Zen Magnets (5mm spherical magnets used for creative building projects and stress relief). These magnets are strong enough to show an obvious pattern on the viewing film, although you must take care to be gentle with the film, as pinching or folding can cause the film to become damaged and release a small amount of green residue. Do not allow two magnets to be mutually attracted across the film, as if they are allowed to come together, the pinching force will likely damage the viewing film. Damaged areas of the film will permanently remain a fixed color, and therefore not respond to fields in this region.

I bought this just for my own fun to visualize magnetic fields, and it works great. It clearly shows the direction and strength of the fields that you place it on. I will note that one of the sides of the paper is rough, which I assume is the actual magnetic viewing bubbles, so I have been careful not to let that side get scratched because I bet it would damage the bubbles there.

Pratique et ludique pour montrer les champs magnétiques.

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思ったより面白くなかった。

Es justo lo que esperaba, al principio la lámina es verde, al pasarle un iman se oscurece pero no por eso dejan de verse los campos magneticos. Te ahorras las limaduras de hierro en los experimentos.

Works grate my sun loved it