Colorful clock using birefringent plastic and polarized light

This clock is made from clear, birefringent plastic, polarizing filters, and an LED backlight. For more information, go to
http://sites.google.com/site/colorclocks

Category:

Science & Technology

Tags:

• clock
• color
• gear
• birefringent
• polarized
• light

[singhp2]

Colorclocks,

Could you explain how the birefringent plastic and the polarizing filters created this colorful image and why the colors change over time? Also, what makes the colors be different in different areas of the clock? Thank you in advance.

[colorclocks]

I put a link in the description section to a web page with more information.

The short answer is in three parts:

1) Birefringent material rotates the plane of polarization of light.

2) Light polarized by the first filter does or does not make it through the second filter, depending on how much its polarization got rotated by the plastic between the filters.

3) The amount the polarization gets rotated depends on the color of the light, and on the type and thickness of the plastic.

[a4mohit]

this only happens when ur recording the clock, right???

[colorclocks]

I'm not sure what you mean -- what only happens when I'm recording? If you mean the color changes, then no, they happen whether or not you're recording. It would not have been worth the effort if the effect only showed up on camera.

The video is a reasonably accurate rendition of the appearance of the clock, though the colors look a little different in person, because your two eyes see slightly different colors (because viewing from different angles). The effect is a little weird.

[silverpizza100]

i want one :O)

[holycrapapie]

This one's got to be boring on LSD

[MLTech]

cool