Indoor lightningfest: 8 to 12 inch sparks from blanket

Dan Robinson

I've posted about these before, but tonight the dry air inside my house and some other unknown factor(s) have resulted in extreme conditions for static electricity discharges. Using the blanket/hair charge separation method, I have been getting unbelievably long sparks - the longest non-machine (non Tesla/Van De Graaff, etc) generated sparks I have seen. Sparks reaching up to a foot in length were common tonight!

These sparks are amazingly intricate and beautiful, with hundreds of crisp upward-branching channels above a brighter main channel which terminates on your skin surface. I know this sounds geeky, but trust me, if you have any appreciation for lightning and have never seen these, you are missing out!

Photographing these with conventional cameras is proving problematic, despite their visual brightness to the naked eye. The only way I can get any images of these is with the VX2100, iris wide open and shutter speed down to 1/4 of a second. This yields a very grainy, almost useless image except to show the size and shape of these miniature upward-moving discharges. They are near-exact miniature 'replicas' of the upward-branching lightning common with TV towers and antennas.

Here is one of the longest ones I was able to catch with the camera. My entire hand is visible in this shot which provides a reference point for the scale. The spark actually extends past the top of the frame. The bright section of the spark is a little less than 2 inches long. The branching begins at the top of the bright section of channel.


Here are a couple more grabs. The longest of these is around 8 inches from the base to top of the branching. Again, the bright lower section is between 1 and 2 inches long.

To create these, you need to drag a dry blanket over your head and hold your fist about a foot in front of your face. I know that sounds funny, but it works.
Dan thats pretty cool. Did it hurt.

I do however think you have to much time on yours hands :D
And your syptoms of SDS are getting worse you need a good dose of storms to be cured.
Look at the size of those LOL.

I can't imagine what I might be able to create out here in the desert. We're having dewpoints of -1 and -2, not uncommon for this time of year in the desert.

It doesn't take much to generate a spark. If I walk only a few steps on a carpet I'll get a good zot.

Did you try some ultra-sensitive film, such as 1600iso for candlelight?

LOL that's cool.
It's bad out here too. My dog walked across the bed the other night and just touched his nose to my laptop computer and ZAPP! It was loud and my computer immediately turned off. I was thinking OH CRAP! HE JUST FRIED MY COMPUTER! but it booted back up ok.
Last night we cleared out, and the outside dewpoint was 11, which helped. Of course with the heating inside, it was a lot drier.

These sparks seem to be low-current and don't really hurt, at least not as much as the human-to-pet sparks seem to :).

I really wish I had a way to capture these things as you see them. A few years ago I tried 1600 black and white film processed at 3200ASA - nothing but black frames. I'm thinking a low-light camera like the ones being used for sprite and jet photography would work. I just want to freeze-frame one to look at it!

If we get a repeat tonight I might try some different settings on the camera.

I've also been getting nailed with huge sparks every time I get out of my car. I guess it could be SDS, but I love it.
Here's some thoughts based on a little research....

The sparks you're trying to capture radiate (I think) more in the ultraviolet band. These wavelengths are filtered by design in available emulsion formulations (even though silver-halide is itself rather sensitive to uv). In addition, the design and glass formulation of complex lenses filters uv as well.

Sooooo. Without getting exotic and coating your own plates or trying to find fast spectroscopic film, a conventional camera and gelatin emulsion isn't giving you nearly the effective ASA you're shooting for.

Digital CCDs are intrinsically sensitive to uv, hence the better imaging of your video camera. Video cameras have less fancy glass, too. What I'd try is a digital camera with no filters and as simple, uncoated optics (i.e. a cheapie lens) in front as possible.

What a neat project!

[ed.: Since the experiment is inherently dangerous for electronic cameras, I'd also be sure to be static-charge free when popping the shutter, using a grounded assistant or timer.]
Here's a Paint Shop approximation of what these discharges look like. This is what you'd see if you had a camera that could capture them clearly.


Bill, that video is a classic!
The fun continues tonight, courtesy of continued low dewpoints.


Intense discharges using metal rod to light switch panel. Now *these* are painful. This one is with the camera at normal exposure settings (1/60th second).


Orange glow at contact point, like the real thing.

More mini-tower lightning.

Turns out that 1/15 second seems to work better than 1/4th second.

David is right - I think a good digital camera may be able to get these.
Bizarre. I absolutely *hate* it when I get shocked. Pisses me off... why on earth would I want to do this on purpose??? It's soooo damn dry out here in western KS. This needs to change.