Why does a bottle change colors when you put it in between polarization plates and move them?

Question

Why does a bottle change colors when you put it in between polarization plates and move them?

I'm lost.

Answer 1

When the bottle is made, it is pulled and stretched in certain ways, causing the plastic polymers to align in those directions.  Aligned molecules like these act as polarizing filters.  However, they may cause more or less polarization for different wavelengths (colors) of light, and at different angles.

When you rotate the polarization plate, you may be effectively 'selecting' angles that polarize certain colors more or less.

The polarization plate itself is probably specially designed to polarize all colors of light equally.