| Author | Message | ||
     Krystyna Perez |
Dear Mr. Field, I am an 8th-grade honors student and have been researching electromagnetic levitation for the past 6 weeks. I wanted to do an experiment where I could levitate a petri dish of bacteria to see if there was any effect on it's growth. I had seen a lot of examples of MAGLEV devices on the internet, and even though I knew it would probably be very difficult, I was hoping I could make this work. Yesterday, I met with a scientist from Amgen to discuss my project. He told me that a levitation project was not possible, and that only the strongest magnet in the world would work...and that it only worked for a frog. My mom helped me find lots of sources on the internet and we saw lots of devices. Some had instructions on how to build them, and some just had them for sale. With all of these websites saying that levitation is possible, and that it CAN be done with supplies from places like Radio Shack, I don't understand why I was told that it was IMPOSSIBLE. I know that maybe the petri dish is too big, or too heavy, but is it possible to try it? I would really like your opinion about this since I've already spent 6 weeks on it, and I'm supposed to turn in the "rough draft" of my report in 2 days. If I have to change my whole project, I need to make a decision right away. If you don't think this project is possible, then maybe you could suggest something else to do with electromagnetic levitation...I'm really want to do it! Thank you for your time. Please let me know what you think as soon as possible. Krystyna Perez | ||
| Simon Quellen Field (Sfield) |
I think the fellow from Amgen was assuming you wanted the bacteria to experience weightlessness. In other words, the molecules in the bacteria would have to be levitated, rather than the dish on which they grew. If you simply levitate the dish, then the bacteria would still experience the earth's gravity, since they won't be able to tell the difference between a levitated dish and a dish sitting on the table. Any effect on the bacteria would be due to the magnetism or the extra light they would get from below. Diamagnetic levitation will work with any diamagnetic substance. Some things are more diamagnetic than others. Bismuth and certain pyrolytic graphites are very good. But oxygen and water are also diamagnetic, and so you can levitate the frog if you have enough power. With some help (financially and mechanically) you might be able to build a decent sized water cooled electromagnet. Such a magnet might have enough power to levitate very small drops of water, or pinhead sized chunks of agar, in which your bacteria could grow in weightlessness. I'm just guessing, but 5 or 10 kilowatts of power may be enough. That's 40 amperes of current at 250 volts, which is within the capabilities of a 50 amp circuit breaker in a typical house. If you're paying 60 cents per kilowatt hour of electricity, that would be about 6 dollars an hour. Without looking up real numbers and doing calculations, I would guess that the cooling water might be a couple gallons a minute. If you could find a good use for the hot water, it might not be a total waste. If you don't need the bacteria to experience weightlessness, then things are a lot easier. Make the petri dish really small, like a quarter of an inch in diameter. In other words, simply cut a small piece of agar and place it on the little magnet in the levitator on my web page. You will need to cover it with a small piece of plastic wrap so the agar doesn't stick to the bismuth plate while you adjust the magnets to make it levitate. The main problems will be making sure that the agar is very thin (since there is very little room between the magnet and the bismuth plates), and in keeping the magnet levitating for long periods of time, since small temperature changes can make the magnet fall or rise enough to make it touch one of the plates. Of course, I am an amateur at this stuff. The real experts in magnetic levitation are Bernard H. Meuller (bmueller@loop.com), Lee Heflinger (use bmueller@loop.com to get to him as well), and Martin Simon (msimon@physics.ucla.edu), and Andrey Geim. If you haven't seen this web page: "http://www.sci.kun.nl/hfml/phystod.html" you should read it... | ||
| Joshan |
hi.i have been trying to build up an fm radio, but i have not found any circuit diagram including list of components and i wanted to build one with an extended frequency response, that is, it can pick up signals more than 108MHz.i would very much appreciate if you could,provide me with a circuit diagram and list of components. what would happen if you connect 1 more variable capacitor to the a.m radio circiut(increase the capacitance)?? you ought to know that i am in my GCSE year and that i have limited knowledge of electronics. thank you very much for your help+the website is great!!! | ||
| Simon Quellen Field (Sfield) |
You need this book. On the web try here, or here. There are dozens of web sites with this information. Do a Google search on "fm radio circuits". | ||
| Anonymous |
You may like the look of this project..Complete with build instructions.. http://www.techlib.com/electronics/allband.htm ..AB.. | ||
| Anonymous |
If you have made a contraption to levitate magnets- and you used ceramic ring magnets to be the top magnets that supply the magnetic pull (which does work) and you are testing whether Pyrolytic Graphite or Bismuth levitates a magnet better- (and I am testing this by measuring the distance from the ceramic ring magnets and the Pyrolytic Graphite/Bismuth) Does the ceramic rings being closer to the magnet prove the material more diamagnetic or less? sorry that was a bit confusing ~DS~ | ||
| Simon Quellen Field (sfield) New member Username: sfield Post Number: 220 Registered: 12-2004 |
The height of the magnet is determined by the strength of the top magnet and the strength-to-weight ratio of the floating magnet. The diamagnetic strength of the plates determines the distance between the plates and the floating magnet, for any given top-magnet/floating-magnet combination. In other words, if you keep the magnets the same, a better diamagnetic material will give you more space. If you keep the diamagetic material the same, a better top magnet will give you more space. If you keep the top magnet and the material the same, a stronger or lighter floating magnet will give you more space. | ||
| Anonymous |
yeah but like - Pyrolytic Graphite is 3 times more diamagnetic then Bismuth. So graphite would levitate a magnet better. Am I right so far or am I way wrong? But anyway- If that is right- how would I prove it? (I need to be able to do a graph on it) ~DS~ | ||
| Simon Quellen Field (sfield) New member Username: sfield Post Number: 221 Registered: 12-2004 |
Diamagnetism falls off with the fourth power of distance. That means that if something is sixteen times as diamagnetic as something else, it will push with the same force twice as far. Glue two magnets to a stick so that their south poles face north. Hang the stick on a string so it makes a compass. Place some bismuth near the north end of the stick, and measure how far away the magnet is pushed. Do the same thing with graphite, being careful to place the graphite in the same place the bismuth was. | ||
| Anonymous |
ok cool- what size magnets are we talking about here (I need to know if I have them) and an even more retarded question- I am so new with magnets and know about zilch. So how in the world do I know which is their south poles? By the pull or push? And Thank you soooooo much. I really appreciate this. ~DS~ | ||
| Simon Quellen Field (sfield) New member Username: sfield Post Number: 222 Registered: 12-2004 |
Any size magnets will work. There are three easy ways to know which pole is north. The first one is to use a compass. The second way is to float the magnet on something and see which pole faces north. The third way is to just let the magnets stick to one another, then attach them to the stick with their poles facing the same way they did when they were together, and then let the stick point north. | ||
| Anonymous |
thank you so much. If I run up against any problems I'll let you know. Thank you again. ~DS~ | ||
| Anonymous |
Do you by any chance have a picture or drawing of how the thing you are telling me to make?? Or do you know where I could find one - because I want to see if i am doing it right. ~DS~ | ||
| Simon Quellen Field (sfield) New member Username: sfield Post Number: 223 Registered: 12-2004 |
You're just making a big compass. Big makes it easier to measure the distance it deflects when you bring the diamagetic materials near one end. You don't even need two magnets -- one should do, as long as there is a weight at the other end to balance the stick on a string. | ||
| Anonymous |
It isnt working to well.......ok exactly - I have a peice of round wood (thin) attached to a string. On the wood I have 2 magnets glued at the end. The north pole is facing up the wood and the south facing down. Then I put some bismuth at the north and then a magnet- the magnet hoped to the wood/string/magnets. What did I do wrong? ~DS~ | ||
| Simon Quellen Field (sfield) New member Username: sfield Post Number: 224 Registered: 12-2004 |
I think you meant to say "hopped". You don't need a third magnet for anything. Your stick should be pointing north and south, acting like a compass because of the magnets glued to it. If you place a piece of bismuth near one of the magnets, you should be able to push the magnet, causing it to move without touching it. Let the stick settle down until it is still. Mark where it rests by placing something non-magnetic that points at the magnet. If the stick is hanging near the table, you can just place a piece of paper under it and mark where the magnet is. Now move the bismuth up to that mark. The magnet will move away from the bismuth. Measure the distance between the magnet and the bismuth. Repeat using other diamagnetic materials, such as graphite, pyrolytic graphite, silver, ice, or whatever you have on hand. | ||
| Anonymous |
Thank you so much for putting up with me. I tested many materials and they all worked. Thank you for your time. ~DS~ :-) | ||
| Anonymous |
Just wanted to follow up with a thank you for all of your help with my magnet experiment for the science fair. I WON 1ST PLACE! Thank you so much. Now I get to go onto the state fair. Im so excited. Thank you again. Your time is greatly appreciated. I'll keep you posted. ~DS~ | ||
| joshua Unregistered guest |
COOL!!!!!!! | ||
| Anonymous |
O yeah- I forgot I was going to update you and I remembered when my friend was looking at my awards. I won the California State Fair for Large Schools Phisical Science 1st place. Just thought I would let you know- cause you helped me so much. Thanks again ~DS~ | ||
| Simon Quellen Field (sfield) Senior Member Username: sfield Post Number: 407 Registered: 12-2004 |
Excellent! | ||
| labview1958 (Labview1958) New member Username: Labview1958 Post Number: 1 Registered: 6-2005 |
I heard there is a superconducting tape being sold. By any chance does anyone know where to get one? Is it expensive? I also would like to buy some superconducting powder. Where can I get some? Is there such a thing as a superconducting paint? | ||
| Anonymous Posted From: 144.134.90.87 |
superconductive tape and powder? I think its likely you have been tricked. | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 622 Registered: 12-2004 |
See this page. Superconducting tape, wire, powder, and disks are being sold, and all are within a reasonable budget for an experimenter. The most expensive part of experimenting with the superconductors will be the Dewar for the liquid nitrogen you will need to make them superconduct. | ||
| Anonymous Posted From: 144.134.90.220 |
ahh sorry I was under the impression that he wanted room temperture superconductivity. | ||
| Julian Unregistered guest Posted From: 68.40.155.113 |
Dear Mr. Field, I am a 10th grade honor student and I’m entering a science fair with a lot of stiff competition. I was reading about the article on experimenting with magnetorheological fluids and thought I could use it for a unique and creative project. My research teacher is not much help because he drifts off into space when he talks to a student. I was wondering if you could help me think of any practical applications in the household or a place, you see more fit that can be made with items that are easily obtainable | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 671 Registered: 12-2004 |
You could design a lamp arm whose elbow was in a rubber ball full of the fluid. Move the lamp to the desired position, attach the magnet to the ball to lock it in place. Or use a jar of it as a holder for plastic plant stems. Arrange the plants, then attach the magnet to lock them there. Put a plastic zip lock bag full of the material on your face. Attach the magnet, then pull off a cast of your 3D image and use it as a mold for plaster of paris or paper mache. But you and the crowd on this message board can surely think of some even wilder or more useful applications for a paste that stiffens when a strong magnet touches it and relaxes again when the magnet is removed. The paste does not get rock-hard -- so use large surfaces to magnify the effect. A pencil can be stuck in the hard fluid and rotated, but a spoon will stand up straight in it all day. | ||
| Julian Unregistered guest Posted From: 71.65.15.192 |
Thank you Mr Field for the great suggestions. I was wondering if you know of any place where it would be easier to find a lot of iron/ iron ore pieces for my mr fluid? I am kind of having a hard time finding a way that doesn't involve digging through sand. Thanks again in advanced. | ||
| Anonymous Posted From: 63.17.109.229 |
hey I am an 9 grade studant thiking about a number of science projects. 1 is a i wheeled vehicle unlike the currant i wheeled vehicles capable of carrying a human (me, preferably safely lol). i have a very small budget but i could stretch it. i would like to show how its principals and that it does indeed work by riding it around the gym that the science fair is in. because of that, electric drive is preferable. in a recent Popular Science i saw something kind of like what i want to build. it is called the riot wheel. it's monsterous and gas powered but displays the right principals. i have a lot of time to work on it, so its not very pressing. any help would be, well, helpful. lol. _Mattb_ | ||
| Josh (Unregistered Guest) Unregistered guest Posted From: 72.235.129.42 |
Is a low voltage non magnetic levatation device possible ? | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 820 Registered: 12-2004 |
Yes. | ||
| Cheyenne Bell (Unregistered Guest) Unregistered guest Posted From: 69.111.92.233 |
Sorry, I sent my question through your feed back section. I cant seem to get the Van De Graaff generator to work. It runs but does not generate any power. any advice? | ||
| Josh (Unregistered Guest) Unregistered guest Posted From: 72.235.129.42 |
is there any websites that sell this or is it out of the question ? | ||
| josh (Unregistered Guest) Unregistered guest Posted From: 72.235.129.42 |
the non magnetic levetation device ? | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 878 Registered: 12-2004 |
Cheyenne Bell: If you use the search link in the upper right corner you can find the message threads about the VDG. Search for "vdg", "van de", and all of the common misspellings of the name -- people never seem to be able to spell it right. | ||
| Simon Quellen Field (Sfield) Senior Member Username: Sfield Post Number: 879 Registered: 12-2004 |
Josh: See this, or this, or this, or this, or this, or this, or this. Google is your friend. | ||
| Maria Teresa Pombo (Maria_teresa) New member Username: Maria_teresa Post Number: 3 Registered: 8-2007 |
Hi! I sent a reply today to the e-mail you were so kind to send us yesterday directing it to an address you sent me that is different from the one here and my e-mail system did not allow me to send it there. Therefore, I re-sent, earlier this morning, the same e-mail with the questions I still have to the e-mail address here begging for your prompt and valuable help. We are in dire need to know the answers to our questions since my son has until tomorrow to submit his topic for the Science Fair and we are concerned about several issues. We are wondering whether you have found time in your busy schedule to see the e-mail. We deeply thank you for your time!!! |
