Lego Optics Lab: Polariscope

Introduction

A Polariscope is a simple and fun way to view the rainbow colors in clear plastic objects such as flatware, tape dispensers, etc. The rainbow colors you see through the polariscope is the photoelasticity (a technical word for viewing the stress distribution) of the object you are looking at when you use the polariscope.

Lego Optics Lab components needed for this experiment:

• Lego Optics Lab: Mobile Phone/iPod Mount

• Lego Optics Lab: Filter Rotator

I used my iPod running a flashlight app for my source of polarized light. The polarized filter that I installed in the filter rotator came from a handheld electronic game that the batteries leaked and ruined (I try to salvage what I can from broken things before recycling them) and cut it to fit on the Lego turntable gear.

Here's the iPod with the flashlight app running and the polarized filter rotated to show the white background (of the iPod running the flashlight app):

Here's the iPod with the flashlight app running and the polarized filter rotated to show the white background AND a tape dispenser in front of the iPod:

Here's the iPod with the flashlight app running and the polarized filter rotated to show the DARK background AND the tape dispenser in front of the iPod. Now you can see the rainbow effect -- the fringe pattern (its photoelasticity--the stress distribution in the tape dispenser):