RADIOMETER

Radiometer, retail $9.98 (www.thingsyouneverknew.com...)
Manufactured by (Unknown) for DURO-LITE Lighting
Last updated 09-29-10




It does not emit light of its own, and doesn't use batteries.
But it is a light-powered engine, so I think it belongs on a website about lights.

It looks like a light bulb.
It has a stem press inside like a light bulb.
And it has a partial vacuum like many light bulbs have.
But that's pretty much where the similarity ends.

The radiometer is based on the Crooke's radiometer; a bulb with a partial vacuum inside is fitted with a pin and four vanes - each vane is colored black on one side and white on the other. The vanes rotate when irradiated with light from sunlight, an incandescent light bulb, or a reasonably powerful (>~70mW) laser. If a laser is used, shine it on the black part of the vanes.


SIZE



The radiometer is deceptively simple to use; just place it in sunlight or near an incandescent light bulb, and the vanes inside will happily spin away.



There are no batteries to change or charge in the radiometer; just try not to drop it - if you do and it cracks or breaks, the "vaccume" (vacum, vacume, vacumn, vacuum, vaccuummnne, etc.) inside will be relieved and the radiometer will no longer function.



The radiometer is meant to be used as a curiosity, not as a flashlight meant to be carried around, thrashed, and abused, so I won't try to drown it in the toilet tank, bash it against a steel rod or against the concrete floor of a patio, let my housemate's citty kats go to the litterbox on it, run over it with a 450lb Celebrity motorised wheelchair, or perform other indecencies on it that a regular flashlight might have to have performed on it. So this section of the web page will be significantly more bare than this section of the web page on a page about a flashlight.

I experimented with the radiometer by shining a ~90mW green laser at the black side of the vanes inside, and wouldn't you know it, the vanes began to spin!!!

There are six experiments described in the instructional leaflet furnished with the radiometer.
They are:

What light source works best? (Using different light sources with the radiometer)
What angle works best? (Pretty self-explanatory)
Does a mirror increase the intensity? (Experimenting with a small mirror to speed up the vanes)
Does the Radiometer need direct sunlight? (Also pretty self-explanatory; the short answer is "no")
The Radiometer and heat energy (Using heat from a hair dryer to attempt to operate the radiometer)
Will wind affect the Radiometer? (Using a straw to blow on the radiometer - again, the short answer is "no effect")


WMP movie (.avi extension) showing the radiometer's vanes spinning in sunlight.
This clip is approximately 9.0 megabytes (9,294,880 bytes) in length; dial-up users please be aware.
It will take no less than forty minutes to load at 48.0Kbps.

The movie clip appears to show the vanes spinning very slowly at times;
this is an illusion created by the frame capture rate of the camera.


WMP movie (.avi extension) showing a ~90mW green laser spinning the vanes of this radiometer.
It is approximately 5.4 megabytes (5,617,956 bytes); dial-up users please be aware.
It will take no less than twenty five minutes to load at 48.0Kbps.


WMP movie (.avi extension) showing a ~6mW yellow laser (with IR filter removed) spinning the vanes of this radiometer.
It is approximately 4.0 megabytes (4,226,784 bytes); dial-up users please be aware.
It will take no less than twenty minutes to load at 48.0Kbps.

WMP movie (.avi extension) showing the radiometer spinning while being
irradiated with ~100mW of laser radiation from a Stealth green laser.
This clip is approximately 8.0 megabytes (8,278,276 bytes) in length; dial-up users please be aware.
It will take no less than thirty minutes to load at 48.0Kbps.

That music you might hear in this clip is from the trainer screen for the Commodore 64 game "Wastelands" from ~1989.

I cannot provide any of these videos in other formats, so please do not ask.




TEST NOTES:
Test unit was purchased in late-April 2007 and was received on the afternoon of 05-02-07.

Product was made in India. A product's country of origin really does matter to some people, which is why I published it on this web page.


UPDATE: 09-29-10
This product was destroyed after its vanes were irradiated with the Wicked Lasers Spyder 3 Arctic 445nm 1W Blue Diode Laser, therefore, that dreadful "Failed or was destroyed during/after testing" will be appended to its listings on this website. The product's vanes still rotate, but ***MUCH*** more slowly then they did before.

Let's photograph the damage and see if I can tell what went wrong...*snap*...*click*...and it's off to the Fotomat we go!



Hmmm...there doesn't appear to be sufficient damage to the vanes themselves to cause this behaviour...best guess here is that when the black material incandesced (burned), it outgassed, queering the near-vacuum and/or the gas fill of the "bulb". If the pressure inside the "bulb" increased, that would indeed cause the radiometer to malfunction in this manner.

Here is the video of the radiometer's destruction:



Video on YourTube showing the Wicked Lasers Spyder 3 Arctic 445nm 1W Blue Diode Laser irradiating & burning the vanes of this radiometer.
This radiometer no longer functions properly because it suffered internal damage from the laser!

Medical P/C Argon Laser Safety Goggles were used in front of the camera's lens to allow you to see the vanes of the radiometer incandescing (burning) while being irradiated. Those are the bright yellow flashes you see; the laser's blue radiation is almost completely attenuated by them!!!

This clip is approximately 9.900045345618 megabytes (10,095,846 bytes) in length; dial-up users please be aware.
It will take no less than forty nine minutes to load at 48.0Kbps.