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ShuttleLabs:
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Spaceflight Trainee ![]() ![]()
Joined: Wed Oct 13, 2004 6:56 pm
Posts: 34 Location: Anywhere (Private) ![]() |
I'm moving my post to here. I think I'm safe with Moderators TerraMrs, idiom, eraurocktchick87. I got locked by space cafe's dungeons and dr evolutionist.
------------------------------------------------------------------------------- There's great book called "Bishop boys" Both little religious boys grew up with toy helicopter to Bicycle Shop. Living in 1900s, No levitron were invented. As Today, here's levitron spinning toy. I could do something with Faraday's effect. From my home, not far away from Flushing Airport and New York Times Printing Plant. I could built little model to fly. ![]() Some Frequently Asked Questions About Levitron® Physics Dr. Michael V. Berry What holds the top up? The 'antigravity' force that repels the top from the base is magnetism. Both the top and the heavy slab inside the base box are magnetized, but oppositely. Think of the base magnet with its north pole pointing up, and the top as a magnet with its north pole pointing down (fig 1). The principle is that two similar poles (e.g., two north poles) repel and that two similar poles attract, with forces that are stronger when the poles are closer. There are four magnetic forces on the top: on its north pole, repulsion from the base's north and attraction from the base's south, and on its south pole, attraction from the base's north and repulsion from the base's south. Because of the way the forces depend on distance, the north-north repulsion dominates, and the top is magnetically repelled. It hangs where this upward repulsion balances the downward force of gravity, that is, at the point of equilibrium where the total force is zero. ![]() Why does it need to spin? To prevent the top from overturning. As well as providing a force on the top as a whole, the magnetic field of the base gives a torque tending to turn its axis of spin. If the top were not spinning, this magnetic torque would turn it over. Then its south pole would point down and the force from the base would be attractive - that is, in the same direction as gravity - and the top would fall. When the top is spinning, the torque acts gyroscopically and the axis does not overturn but rotates about the (nearly vertical) direction of the magnetic field. This rotation is called precession (fig 2). With the LEVITRON¨, the axis is nearly vertical and the precession is visible as a shivering that gets more pronounces as the top slows down. The effectiveness of spin in stabilizing a magnetically supported top such as that the LEVITRON¨ was discovered by Roy M. Harrigan (4). ![]() Why doesn't the top slip sideways? For the top it remain suspended, equilibrium alone is not enough. The equilibrium must also be stable , so that a slight horizontal or vertical displacement produces a force pushing the top back toward the equilibrium point. For the LEVITRON¨, stability is difficult to achieve. It depends on the fact that as the top moves sideways, away from the axis of the base magnet, the magnetic field of the base, about which the top's axis precessed, deviates slightly from the vertical (fig. 2). If the top precessed about the exact vertical, the physics of magnetic fields would make the equilibrium unstable. Because the field is so close to vertical, the equilibrium is stable only in a small range of heights - between about 1.25 inches and 1.75 inches above the center of the base. (between 2.5 and 3.0 inches for Fascinations' new Super LEVITRON¨). The Earnshaw theorem is not violated by the behavior of the LEVITRON¨. That theorem states that no static arrangements of magnetic (or electric) charges can be stable, alone or under gravity. It does not apply to the LEVITRON¨ because the magnet (in the top ) is spinning and so responds dynamically to the field from the base. Why is the weight so critical, and why must it be adjusted so often? The weight of the top and the strength of magnetization of the base and the top determine the equilibrium height where magnetism balances gravity. This height must lie in the stable range. Slight changes of temperature alter the magnetization of the base and the top. (as the temperature increases, the directions of the atomic magnets randomize and the field weakens). Unless the weight is adjusted to compensate, the equilibrium will move outside the stable range and the top will fall. Because the stable range is so small, this adjustment is delicate - the lightest washer is only about 0.3% of the weight of the top. Why does the top eventually fall? The top spins stable in the range from about 20 to 35 revolutions per second (rps). It is completely unstable above 35-40 rps and below 18 rps. After the top is spun and levitated, it slows down because of air resistance. After a few minutes it reaches the lower stability limit (18 rps) and falls. The spin lifetime of the LEVITRON¨ can be extended by placing it in a vacuum. In a few vacuum experiments that have been done the top fell after about 30 minutes. Why it does so is not clear; perhaps the temperature changes, pushing the equilibrium out of the stable range; perhaps there is some tiny residual long-term instability because the top is not spinning fast enough; or perhaps vibrations of the vacuum equipment jog the field and gradually drive the precession axis away from the field direction. Levitation can be greatly prolonged by blowing air against an appropriately serrated air collar placed around the top's periphery so as to maintain the spin frequency in the stable range. Recently a LEVITRON¨ top was kept rotating for several days in this way. But the most successful means to prolong the top's levitation is with Fascinations' new PERPETUATOR ¨, an electro-magnetic pulsed device which can keep the top levitating for many days or even weeks. Here's more FAQ link : http://www.fascinations.com/LevitronScience.htm Special thanks to Fascinations and XyNexT William G. Hones Fascinations Toys & Gifts, Inc. www.levitron.com Last edited by ShuttleLabs on Wed Nov 10, 2004 1:54 pm, edited 5 times in total. |
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Space Station Commander ![]() ![]()
Joined: Sat May 22, 2004 8:59 am
Posts: 578 Location: Zurich ![]() |
Still stealing images without giving due credit ... this time you've stolen the above image from HERE.
Thief. An annoying one at that. DKH. _________________ Per aspera ad astra |
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Spaceflight Trainee ![]() ![]()
Joined: Wed Oct 13, 2004 6:56 pm
Posts: 34 Location: Anywhere (Private) ![]() |
Dr. Keith & author you belong to evolutionist group that would be Clonaid. Go back to space cafe's dungeon forum!
![]() I got my King James bible on - Time for me to read slowly. ![]() |
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Space Station Commander ![]() ![]()
Joined: Sat May 22, 2004 8:59 am
Posts: 578 Location: Zurich ![]() |
ShuttleLabs wrote: Dr. Keith you belong to evolutionist group. and you belong in a padded cell ... why didn't you leave this trash in the Space Cafe? Even I was mostly satisfied with it there. Except the parts you rip off from other people of course. Now if I was given free reign on this forum, which I'm not, I would call you a cold turd from the tundra of imagination ... but since I do not have free reign here, I shall refrain. Instead I shall gently ask you to ... Go. Away. DKH _________________ Per aspera ad astra |
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Moon Mission Member ![]() ![]()
Joined: Tue Oct 05, 2004 5:38 pm
Posts: 1361 Location: Austin, Texas ![]() |
Yes, I have played with this toy. One spinning magnet hovering above a magnetic base. It may give you some ideas for a maglev train, but not a space craft.
And if you use superconductors, you don't even need to spin the hovering part! (I have played with one of those too). |
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Spaceflight Trainee ![]() ![]()
Joined: Wed Oct 13, 2004 6:56 pm
Posts: 34 Location: Anywhere (Private) ![]() |
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![]() Hey, Molecular Biologist. Intelligent design base on Evolution Science. You can create and altar DNA. "ABAB" genes -- Intelligent creatures such as Human Clone, Cloning dolly, alligator DNA into Human DNA. You call yourself Intelligent. You see that evolutionist UFO. There is no Airbag and Parachute. hahah. Intelligent design. I find it entertaining. ![]() You would use different contrast Evolutionist: Galileo Charles Darwin Human Clone Scientist Cloning food process. you can create Athrax you can create millions of diseases Weapons of Mass destruction Clonaid Creationist: Leonard Da Vici Columbus Issac Newton Founding Fathers of America Wright brothers Louis Pasteur Thomas Edison Alexander Graham Bell NASA Space Shuttle http://en.wikipedia.org/wiki/Creationis ... _evolution Last edited by ShuttleLabs on Wed Nov 10, 2004 8:34 pm, edited 2 times in total. |
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Spaceflight Trainee ![]() ![]()
Joined: Wed Oct 13, 2004 6:56 pm
Posts: 34 Location: Anywhere (Private) ![]() |
Quote: "Yes, I have played with this toy. One spinning magnet hovering above a magnetic base. It may give you some ideas for a maglev train, but not a space craft. And if you use superconductors, you don't even need to spin the hovering part! (I have played with one of those too)." - campbelp2002 ![]() Earth's latitude <I don't think Superconductors could levitate higher. Something about ICE and magnetic field. I have is unfinish Gyroscope engine... Inner Engine .............................................................. ![]() Last edited by ShuttleLabs on Wed Nov 10, 2004 9:13 pm, edited 2 times in total. |
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Spaceflight Trainee ![]() ![]()
Joined: Wed Oct 13, 2004 6:56 pm
Posts: 34 Location: Anywhere (Private) ![]() |
I love those Startrek mini-pods
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Moon Mission Member ![]() ![]()
Joined: Tue Jul 15, 2003 8:46 pm
Posts: 1218 Location: Kapellen, Antwerp, Belgium, Europe, Planet Earth, the Milky Way Galaxy ![]() |
ShuttleLabs wrote: I'm moving my post to here. I think I'm safe with Moderators TerraMrs, idiom, eraurocktchick87. I got locked by space cafe's dungeons and dr evolutionist. This is a public forum. But to have a "public" forum, we need to have some limitations. As example, we have to make sure, that the forum does not changes into a battle field, that's why we have to "ban" people who're unable to use or actually have the skills to have a conversation with respect of others, it includes posting information that starts a flame war. You have the right to share your intrest and opinions, but there're "limitations", freedom and rights can only be gained if you respect other values. ShuttleLabs, do you know why we post a link & author etc... with our news posts on our news site ? "copyrights" and respect.... Also respect to other forum users (even if they do no always respect you), is something you're missing. This time no moderators, but "the main administrator" who locks this topic, if you do not agree, you can discuss it using e-mail xprize@gmail.com . _________________ Heavier-than-air flying machines are impossible. - Lord Kelvin, 1892 |
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