The ferritate effect is when an object in today's case a glass rod when it's in a magnetic field affects the polarization. So we have our vertical polarized light going in, the analyzer polar right over here in a screen. We're gonna see what's going on. Here's a solenoid which we'll use to create a magnetic field. Tuck inside the solenoid is a glass rod. I've got another one pulled out here so you can see what it looks like. It's just literally just a transparent rod inside a holder so it fits inside the solenoid. So that's already tucked inside the solenoid. First I'm gonna cross the polarizers so we're we're extinct extinct beam is blocked. All right then I'm gonna insert the ferritate rod in here. So I can see like going through it. All right and you can see very faintly the spot has come back just a little bit indicating the rod itself. Even without the magnetic field is slightly by-referringent because I can't actually zero out that little bit of light there. No matter how crossed I get the polarizers even when there are a hundred percent crossed a tiny bit of light leaks by. So the rod the glass rod itself is it's probably very slightly by-referringent but that's independent of the effects we're looking at. We want to know what happens now when I apply the magnetic field. So over here there's a power supply and basically I'm just gonna turn it on and we can see we're now running about 3.1 amperes through the coils. There's a magnetic field in there. You see our spot has got a little bit brighter now and I can try zeroing it out again. I find I have to move just a little bit. The rotation is very tiny. Alright so when I find the minimal now I find I've rotated it about two degrees counterclockwise, two degrees counterclockwise. Now I'm going to turn that magnetic field off and read zero. There. And then I'm going to reverse the magnetic field just by reversing the leads on the power supply over here and turn it back on again. 3.1 amperes. The beam is now a little brighter and now I see I have to rotate now about two degrees clockwise now. So the direction of rotation has changed when I reverse the magnetic field for the for the soul line. And this is what we call the DC ferreter effect because we're playing a constant magnetic field and so you just get a rotation proportional to the size of the B field. Using a setup that was really difficult to measure how big that is because at the maximum output of our power supply we just get a barely detectable rotation.