Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: ciniva on 23/09/2017 13:40:43

Title: Is it possible to make a shield to block a magnetic field?
Post by: ciniva on 23/09/2017 13:40:43
Can anybody tell me, is there a chance to make a shield from a magnetic field?
If there is a possibility, what materials should I use?


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Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: Bored chemist on 23/09/2017 14:09:01
An iron plate would do the job.
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: Colin2B on 24/09/2017 07:19:55
As @Bored chemist  says an iron plate will do the job as will sheet steel. You have to make sure that the metal does not saturate, so it will work as long as you aren't using extremely powerful magnets. You also need the shield to extend beyond the length and width of the magnet or you will get leakage around the sides. Best to experiment.
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: ciniva on 24/09/2017 08:05:20
You have to make sure that the metal does not saturate, so it will work as long as you aren't using extremely powerful magnets
Thanks for the advice.
Do you mean a neodymium magnet grade N52 or N50M.
Will it the steel sheet or iron plate, successfully have effect on the said magnets?
btw: I have a galvanized sheet metal.
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: ciniva on 24/09/2017 09:11:27
I've found on YouTube some video presentations with materials like Giron and Mumetal. (I do not want set link to here, I do not violate the forum rules, but if the moredator permits me I will include a link to youtube)
Since there are a lot of false (fake) presentations there, what do you think about these materials?
Is it worthwhile to buy these materials (especially Giron that advertises on youtube)
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: Bored chemist on 24/09/2017 09:38:37
Mu metal has been used for years as a magnetic screen.
It's a little more effective than iron, but a lot more expensive.
As far as I can tell giron is similar.

What are you hoping to achieve?
If you just want to put a box round a magnet so you can send it by post without annoying the carrier, then a biscuit tin would do the job fairly well.
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: ciniva on 24/09/2017 19:41:37
No, I do not want to send a magnet anywhere.
I want to block the magnetic field.
I want to construct two separate magnets as shown below

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Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: Bored chemist on 24/09/2017 22:34:21
If you are trying to make a "magnet" with just one pole then you are wasting your time.
https://en.wikipedia.org/wiki/Magnetic_monopole
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: Kryptid on 25/09/2017 01:14:41
If you are trying to make a "magnet" with just one pole then you are wasting your time.
https://en.wikipedia.org/wiki/Magnetic_monopole

I am admittedly curious as to what would happen if you constructed a shielded magnet like the type shown in post number 6. Would the magnetic field stop working altogether?
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: ciniva on 25/09/2017 09:26:41
If you are trying to make a "magnet" with just one pole then you are wasting your time.
No, I do not want to make a single-pole magnet. I just want to prevent the magnetic field out of the shield.

Would the magnetic field stop working altogether?
And I'm interested in that :)
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: ciniva on 03/10/2017 17:43:11
I am admittedly curious as to what would happen if you constructed a shielded magnet like the type shown in post number 6. Would the magnetic field stop working altogether?
Hi Kryptid
I want to inform you. I made a magnetic shield around the magnet, in fact I made a single-pole magnet.
You can see the video on a link (if I do not violate the forum rules by placing a link and if the moderator does not delete the link).
https:// www.youtube.com/watch?v=TDqz3eqjI5g&feature=youtu.be
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: Bored chemist on 03/10/2017 20:33:33
That's not a monopole.
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: evan_au on 04/10/2017 09:39:06
Quote from: ciniva
I made a magnetic shield around the magnet, in fact I made a single-pole magnet.
The magnetic shield does not eliminate a pole, it just redirects the magnetic lines of force.

Please do this experiment:
- Place a sheet of paper over the new shielded magnet you have made
- Sprinkle iron filings on the paper, and tap it until they form into lines
- Take a photo
- Post the photo here.

I suspect that the magnetic shield will now become the "missing" pole.
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: ciniva on 04/10/2017 13:58:43
That's not a monopole.
I do not claim to be a monopoly magnet. It's just an object that prevents the other pole magnet from acting outside the magnetic shield. Thus, the object behaves like a monopoly magnet.


Please do this experiment:....
I will do it in the next few days
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: Danne on 04/10/2017 17:17:48
Really excited to see what is going to happen. How large is the magnet in your final project ?
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: Colin2B on 06/10/2017 23:40:05
I suspect that the magnetic shield will now become the "missing" pole.
I suspect the same, see

This is the key to possible solutions that I want.
link: https://www.thenakedscientists.com/forum/index.php?topic=71465.0
Looking at that link I see a comment:
I am admittedly curious as to what would happen if you constructed a shielded magnet like the type shown in post number 6. Would the magnetic field stop working altogether?
I think Kryptid is right. The magnetic field lines will flow through the shielding material from the enclosed pole and at the open end the field lines will try to take the shortest route to the open pole - the surrounding shielding will act as the opposite pole. You will have made something similar to a horseshoe magnet where one pole (the outer pole) surrounds the inner one, this means the field will not extend out as far as an unshielded pole. However, I think you will need to leave an air gap between the poles otherwise the field extent will be minimal.
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: Bored chemist on 07/10/2017 07:12:31
What you have made is something very much like the magnet in most loudspeakers.
http://practicalphysics.org/model-loudspeaker.html
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: ciniva on 07/10/2017 16:05:35
How large is the magnet in your final project
Neodymium disc magnets 6 pieces connected to the stack.
Sprinkle iron filings on the paper, and tap it until they form into lines
As I promised, you can see everything in this video
https:// www.youtube.com/watch?v=myqCHp22nGU&feature=youtu.be

I'm interested in the following:
Can a 'lessEMF' magnetic shield (on youtube there is video), prevent magnetic field strength from neodymium magnets?
Does anyone have any experience?
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: alancalverd on 07/10/2017 16:25:49
Magnetic field lines are equipotential contours, so they must form closed paths. The diagrams are incomplete.
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: ciniva on 12/10/2017 20:38:44
The diagrams are incomplete.
It's just an experiment.

Nobody  did not answer on my question in post #17. Is there anyone in this forum have of real experience with "lessEMF"?
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: evan_au on 14/10/2017 05:21:06
Quote from: ciniva
I'm interested in the following:
Can a 'lessEMF' magnetic shield (on youtube there is video), prevent magnetic field strength from neodymium magnets?
Do you mean this video? (there are many that fit the description you provided...)
He observes that you can't create a magnetic monopole.

He also shows how you can shield a neodymium magnet.
- These are quote strong magnets
- Thicker shielding works better
- MuMetal does not work well, because it saturates in strong magnetic fields.

Quote
As I promised, you can see everything in this video
https:// www.youtube.com/watch?v=myqCHp22nGU&feature=youtu.be
Thanks for posting the video showing the construction of your magnetic shield, and the pattern with the iron filings. Videos certainly can give a good idea of what is going on!

Unfortunately, the paper hides the orientation of the magnet underneath, and I don't see how the magnetic fields outlined by the iron filings relates to the description printed on the paper.

Could you please repeat the iron filing experiment, but first show us the magnet, then put the paper over the top, and then show the iron filings pattern?
Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: ciniva on 14/10/2017 18:34:14
Do you mean this video?
That's that video. I asked the question (in comment) but I did not get the response from the video author.
He also shows how you can shield a neodymium magnet.
How much do I know about this video by using the author "Ferrite magnet"?
Quote
Ryan Walsh - 7 months ago
Hello Sir. Nice presentation
Would you be able to tell me the type of magnet that was used. Was it a N-52.. or something less.
I bought and Received the material today from your company.

Author: LessEMF - 4 months ago
Ferrite
I think in a single comment (Ryan Walsh) read the question and answer, am I right
Could you please repeat the iron filing experiment, but first show us the magnet, then put the paper over the top, and then show the iron filings pattern?
On this URL link I've set up a video on your request.
www.youtube.com/watch?v=UoGLhb7lLm8&feature=youtu.be

Title: Re: Is it possible to make a shield to block a magnetic field?
Post by: ciniva on 18/10/2017 19:32:47
Could you please repeat the iron filing experiment, but first show us the magnet, then put the paper over the top, and then show the iron filings pattern?
I was expecting your comment ;)