This project recreates Faraday's 1845 experiment that revealed the fundamental nature of light: electromagnetic waves.
• In 1845, Michael Faraday used a powerful electromagnet to rotate the polarization of a beam of light, unifying electromagnetic force with light in one of the most elegant and seminal experiments ever.
• Two decades later, James Maxwell confirmed this with his classical electromagnetic equations which showed that light is actually an electromagnetic wave. It wasn't until the 1960s, however, that Faraday rotation was modeled quantum-mechanically.
• Today, this effect is called the Faraday effect or Faraday rotation. See the last step in this instructable for real-life applications.
About this project:
• A Faraday rotator is a device that rotates the plane of polarization of linearly polarized electromagnetic waves (such as visible light) passing through matter (a "dielectric" - an insulator) by applying a magnetic field parallel to the direction of propagation of the light. (This is a very informative link: http://www.teachspin.com/instruments/faraday/index.shtml
• I am currently experimenting with the fully functional device that I have built. I made this device to demonstrate Faraday rotation and I am still working on learning the physics behind it in greater depth. This is my senior project for my "WISE" English class. Nice, eh? I get to do Physics for an English class!
• It will cost a bare minimum of $150-200. Take a look at the materials section (Step 3).
• It requires a rather advanced understanding of some topics in physics. The basics are up to you to learn (see bottom of this page to see what they are), but I do my best to explain Faraday Rotation with classical physics in the last steps of this instructable.
For more background Information:
• Watch 20:20 to 21:15 of this video: http://fora.tv/2008/05/01/George_Johnson-The_Ten_Most_Beautiful_Experiments
• This book has a detailed description of the original experiment: The Ten Most Beautiful Experiments (by George Johnson
) (read chapter 6, "Something Deeply Hidden") You can get some of it here: http://books.google.com/books?id=3w83rbjVWZgC&pg=PA75&dq=the+10+most+beautiful+experiments+by+george+johnson+faraday&source=gbs_toc_r&cad=4#v=onepage&q&f=false
• This website has a ton of useful physics that will really help you understand how Faraday rotation works: http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
• Ask the Van is a great reliable resource for answering your physics questions. It is a Q+A that is run by people who really know what they are talking about: http://van.physics.illinois.edu/qa/newquestion.php
This is where I first went to make sure that this project would actually be possible to do. You can see my original questions here: http://van.physics.illinois.edu/qa/listing.php?id=17167
• Being familiar with the following terms would be quite useful if you want to understand Faraday rotation: electromagnetic waves, linear polarization, circular polarization, index of refraction, birefringence, lasers, wavelength, dispersion, Verdet constant, and magnetism.