| Author | Message | ||
     Kathy Noury |
Please help!! I followed the bismuth floating magnet project to the letter except that I couldn't find a soda can with the little dip on the bottom so I used a muffin tin. No matter what I do, (increase magnets, increase, decrease space between the bismuth disk) the rare earth magnet jumps from the top to the bottom and never floats between. Please let me know what else can be done, I have spent alot of time and money (bismuth shot is expensive!)on this project and it is due next week. Thanks! | ||
| Simon Quellen Field (Sfield) |
You didn't say what you are using for the rare earth magnet that you are trying to levitate. If you got it from us, it is at least 46 MegaGaussOersteds in total energy product. If you got it from somewhere else, it may be as little as 15 MGOe. These will not have the power to weight ratio needed to levitate. Decrease the spacing between the magnet and the bismuth plates until you can barely see light between them. Then increase the power of the lifting magnet on top as much as you can. As you increase the power of the top magnet, it will need to be placed higher up before the floating magnet will fall. The best levitation is with a very strong floating magnet, and pyrolytic graphite. We have obtained the strongest permanent magnets available and combined them with pyrolytic graphite in our Levitation Bundle #3 in our catalog, for $9.00. These can be in your hands in 5 days as a backup plan if you order them today. | ||
| Kathy Noury |
I was told that the rare earth magnet (I got it at Radio Shack) is 30 MGOe. Would that be strong enough? Why doesn't it say in the instructions for this project that it needs to be a certain MGOe? Also, why is pyrolytic graphite not given as a choice in the instructions instead of bismuth which is very hard to find and very expensive. Also, what is the larger gold magnet in the levitation bundle #3 used for? Is there any particular strength that the ceramic magnets need to be? What method of shipping is used if I order the levitation bundle? | ||
| Kathy Noury |
If I buy this is it guaranteed that it will work? | ||
| Simon Quellen Field (Sfield) |
To levitate a 30 MGOe magnet, you need a more powerful top magnet than you would with a 46 MGOe magnet, and it will not have as much separation between the magnet and the bismuth. But is has been made to work. The web page that follows the page on bismuth levitation shows pyrolytic graphite levitation, both as a replacement for bismuth in the first design, and as a levitating plate over four magnets. The eighth picture on that page shows a small magnet levitating between two PG plates. Because bismuth and pyrolytic graphite are hard to find, we carry both in our catalog. Now they are both inexpensive, and easy to find. The larger magnet in the bundle can be used as the top magnet, but you probably have a strong top magnet already. The top magnet should be as strong as you can make it. The stronger it is, the better the separation between the magnet and the plates. We ship using United States Postal Service Priority Mail. While they won't guarantee shipping times, we have been seeing packages arrive at U.S. destinations in 5 days or less. International orders usually arrive in 10 days or less, but are more variable. All of our items are backed by a 100% satisfaction guarantee. If you aren't pleased with the results, we will promptly refund your purchase. | ||
| Ryan Somebody |
I ran in to Radishack and bought one of the little 30MGOe magnets you talked about to find out how powerful they were. The problem your having is DEFINITELY being caused by the magnets. They have nowhere near the power I would recommend. I don't see a problem with the muffin tin concept. I'm curious what your using as a lifter magnet, that could be the problem too. I would recommend an adjustable NdFeB but ceramics work too. If you run out of ceramic magnets and time you could probably improvise with a tightly wound coil and a powerful battery ( I would wind the coil AROUND the magnets with the poles aligned ) | ||
| Simon Quellen Field (Sfield) |
The Radio Shack magnets are 27 MGOe, as shown here. The 46 MGoe magnets we carry in our catalog are 1.7 times more powerful. While this may make it easier to adjust the levitation, because the magnet has more separation between the plates and the magnet for the same strength lifting magnet, it is still possible to diamagnetically stabilize a less powerful magnet. You just need a more powerful magnet on top. That said, Radio Shack charges $1.79 for a pair of the 27 MGOe magnets, and we charge $1.50 for our 46 MGOe cubes, but you have to pay at least $5.85 for shipping and wait five days for it to arrive in the mail. We do have a 100% satisfaction guarantee that they will work in the levitator, but I am sure Radio Shack will take back their magnets if you aren't satisfied. It's bad business not to, and they are much better at the business stuff than I am. ;-) So, the bottom line is that you should be able to make the Radio Shack magnets levitate, but it will be easier with stronger magnets. The Radio Shack magnets are uncoated, and will powder away from the effects of moisture and oxygen in the air. We gold plate ours because it looks much better, and the magnets look the same months later. We have found that gold seems to last longer than nickel plating, possibly due to its softness (it doesn't chip off as readily). And both coatings are so thin that they cost about the same. The cubes are also much easier to see moving as they flash between the plates. | ||
| Kathy Noury |
I am using ceramic ring magnets from Radio Shack for the lifter, exactly as it states in the project. My complaint is that you can only put so many ceramic magnets before there are too many and the rare earth magnet is always on the top because you cant get the ceramic magnets far enough away. I feel that the rare earth magnet from Radio Shack will never work because you cant put enough ceramic magnets on top. The strength of the small magnet that is need should be stated in the project material description. I tried 15 ceramic magnets and it doesnt work. Again, as I previously stated it doesnt give the option of using the Pyrolytic Graphite in that project, it may say it in the next project but I didnt read that one. You may carry bismuth but only 2 tablespoons for $17 is not what I call inexpensive. Its a great project when it works I was very facinated at the pictures of it but it is very frustrating getting it floating. The idea of using a tightly wound coil and a powerful battery may be a good idea but this is a project that my 10 year old is doing for school. | ||
| Simon Quellen Field (Sfield) |
If the floating magnet is always at the top, then you may have a powerful enough top magnet to make this work. You just need to get it farther away. You said you can't get it far enough away, I assume because the support column is not tall enough. You can try extending it with another block at the bottom (or use one of our magnets as the floater). I really appreciate the advice (and patience!) you have, expecially for someone who was frustrated by the project. I have used your suggestions and added text to the project to help prevent others from having the same frustrations. It is through feedback like this that the book improves. | ||
| Anonymous |
Dear Simon: I have been reading the message board trying to keep from having the same mistakes as others regarding the floating magnet experiment. Below is a quote you made regarding the change in the instructions for the experiment, please tell me where I can specifically find this as the pages I find do not seem to have the information you are refering to below. Thanks. ---------- By Simon Quellen Field (Sfield) on Friday, March 14, 2003 - 09:15 pm: I really appreciate the advice (and patience!) you have, expecially for someone who was frustrated by the project. I have used your suggestions and added text to the project to help prevent others from having the same frustrations. It is through feedback like this that the book improves. | ||
| Simon Quellen Field (Sfield) |
The section was re-written to make it clearer. I do that a lot. I don't keep the old text that confused someone around. The project really is pretty simple. | ||
| ally (Unregistered Guest) Unregistered guest Posted From: 61.246.7.81 |
please let me know , if an superconducting electromagnet is used to hold a scrap---will it be consuming more energy while holding the scrap than in the stage of not holding the scrap but is in on status. Ally |
