Earlier this year, we took a look at new videos of our popular demonstrations of the polarization of light, demos M7-03 and M7-07. This week, we’re returning to the topic to check out some simulations that let you try this at home!

A faculty member holds two polarizing filters in front of a diffuse light source.

The first simulation, by Tom Walsh at the oPhysics site, lets you model a wave as it passes through a series of polarizing slits. You can independently adjust the angle of up to three such slit-filters, and see how the resulting wave responds. Experiment with it at

The second simulation, created by Andrew Duffy and hosted by Boston University, shows a graph of light intensity as it passes through a series of polarizing filters. Again, you can independently vary the angle of each of three filters, and now you can see how this changes the intensity of the light after each. Try it at


polarized sunglasses, passing reflected (polarized) light at one angle, blocking it at another

Speaking of trying things at home, this isn’t a purely academic question – this is how polarized sunglasses cut the glare from sunlight reflecting off the road without preventing you from seeing where you’re going! Try rotating a pair of polarized sunglasses and see how their effect changes with angle. It may look something like the animation below. We do this in the classroom, too – check out demonstration M7-18

Polarizer Animation by ROGilbert (PD) - a polarizing filter rotates in front of a computer screen, blocking out light at certain angles.