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Science experiment- light and magnetic fields

by Mackanator
Tags: experiment, fields, light, magnetic, science
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Mackanator
#1
Sep21-11, 01:12 AM
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Hello, I'm in 9th grade looking for some interesting topics to do my science experiment on this year. I'm particularly interested in how magnetic fields affect photons. I know photons are electrically neutral but I'm looking for some "what if?" types of questions. I think somehow being able to bend light using electromagnetic fields would be amazing.

I would be thrilled if you could have a discussion regarding light and magnetic fields in this thread.
Such as creating an EM field strong enough to break a photon down to an electron and positron, which would then allow it to have a charge, further allowing it to be bent.

Thanks,

-Mack
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Drakkith
#2
Sep21-11, 07:12 PM
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The strength of a magnetic field required to cause any significant effects in photons is far beyond what you can create at home to my knowledge. But if I might suggest something, could you not do an experiment using magnets and a laser pointer and "verify" that magnetic fields do not bend light within the extent that you can measure them? (And then explain why using valid math or something) I've actually never been in a science fair, so I don't know the "requirements" for an experiment.
Dr_Morbius
#3
Sep21-11, 07:59 PM
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You would also need 1 MeV gamma rays to create electron positron pairs. Those are not easy to come by.

Mackanator
#4
Sep22-11, 09:19 PM
P: 6
Science experiment- light and magnetic fields

Thanks for replies. I am not going to limit my experiment to just shooting a laser at a magnet and tell what happens. I would like to test and explain what happens to electromagnet radiation while in the presence of a magnetic field. I have access to a university lab if need be, I want to do something I cant at home.
Drakkith
#5
Sep22-11, 11:08 PM
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Here's a quote from a Q&A on the University of Illinois Department of Physics page:

Actually, fixed magnetic fields have no effect on light propagating through a vacuum and (even for rather large field strengths) negligible effect on light propagating through most materials. Quark-antiquark pairs form another category of particle (meson) altogether, not light. Light is not composed of charged particles.

The interesting cases where magnetic fields do affect light propagation are in materials exhibiting the Faraday effect. In these materials, a magnetic field can change the way the charged particles (mainly electrons) respond to the light electromagnetic field. As a result, the polarization of the light (the plane in which the electric field points) rotates as the light propagates through the material. The direction of rotation depends on which way the field points.
Here's the link: http://van.physics.illinois.edu/qa/listing.php?id=409

Perhaps you could do something using a material exhibiting the Faraday effect?
Mackanator
#6
Sep22-11, 11:14 PM
P: 6
Quote Quote by Drakkith View Post
Here's a quote from a Q&A on the University of Illinois Department of Physics page:



Here's the link: http://van.physics.illinois.edu/qa/listing.php?id=409

Perhaps you could do something using a material exhibiting the Faraday effect?
Ah, thanks for that! I actually was reading about the Faraday effect early today. I'm not quite sure if I entirely understood it but I would like to include that in my experiment.

I also was reading about the Kerr effect. Is that in anyways related to Faraday effect?
Drakkith
#7
Sep22-11, 11:28 PM
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Not sure. It looks like the Kerr effect causes the refractive index to change in a material, while the Faraday effect causes polarization of light through a material. I don't know if the two are caused by the reasons, but I'd say they are related.

Edit: FYI the Kerr effect is caused by an electric field, while the Faraday effect is caused by a magnetic field.


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