This DIY device is part of the polarization kit that you will get from a MEL Physics subscription:
Subscribe to: MEL Physics (click to see the contents of this great kit).
Simple Polarimeter and Polarization Art: another amazing experiment from the MEL Physics polarization science kit. Geometric patterns of overlapping cellophane tape with color revealed when viewed with linear polarizing filters- create your own polarization art! This kit provides two linear polarizing sheets that when oriented at 90 degrees creates this device that reveals rainbows hidden within the patterns of polarization in the light transmitted by various objects. In the first video the layers of cellophane rotate the polarization of some light frequencies more than others. In the second video the polarimeter colorfully reveals the trapped internal stresses created in many plastics from their formation process (typically cooling of a liquid in a mold). All items shown included in this kit (plus much more).
These inexpensive test cards are available here:
From eBay: BUY NOW Polarization Test Cards
Get some polarizing filter sheets here:
From Amazon: BUY NOW Polarizing Sheets
Explore many aspects of polarization with this kit:
From Educational Innovations: BUY NOW Polarizing Filter Demo Kit
See this short introduction to linear polarizing filters on Hyperphysics, and many more details on polarization from Wikipedia.
Polarization Test Card: light has features that are invisible to the human eye, such as the orientation of its electric field (denoted as polarization), but can be revealed to us by a polarizing filter, used to block light with specific polarization orientations. Inexpensive test cards like this are often found in shops selling polarized sunglasses. The molecular structure of plastics can rotate the polarization of any light that passes through, and this card has such thin layers added to the top of the photo to create the hidden silhouettes seen here.