Geoengineering Watch and the Wagon Wheel Effect

Mick West

Administrator
Staff member
Source: https://www.youtube.com/watch?v=SD1FJUJdi6M


In a recent presentation, Dane Wigington, the Lead Researcher at Geoengineeringwatch.org showed what he said was the effect of "radio frequency" on water, and spoke of his concern on the effects on human health.

The problem is it's not radio frequency that's making the water freeze in mid air. It's not even being frozen by sound. It's actually a harmless trick of the camera called the wagon wheel effect.
Metabunk 2018-01-26 11-49-15.jpg

The wagon wheel effect was first noticed when filming coach chases in old westerns. This effect can freeze objects, like a wagon wheel, if their rotation speed is synchronized with the speed of the camera. You can replicate this effect yourself.

In Wigington's example a water hose is attached to a speaker that's playing a 24 hertz tone, so it's moving the hose back and forth 24 times a second. Seen here in slow motion
Amazing-Water-&-Sound-Experimen.gif

The camera is recording at 24 frames a second so this has the effect of making the water look like it has stopped. But it hasn't, it's just an optical effect, the Wagon Wheel effect

It's unfortunate the Wigington is using this cool science experiment to frighten people, but maybe when people see how easily mistakes can be made it might prompt them consider other claims more carefully.
 
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deirdre

Senior Member.
Here's the video Dane is using. It specifically says you need a specific camera [setting].

upload_2018-1-26_15-34-14.png

The main thing to keep in mind for this project is that you need a camera that shoots 24 fps.

The effect that you are seeing can't be seen with the naked eye. The effect only works through the camera. However, there is a version of the project you can do where the effect would be visible with the naked eye. For that project, you'd have to use a strobe light.

For this project you'll need:

A powered speaker
Water source
Soft rubber hose
Tone generating software
24 fps camera
Tape.
Content from External Source
Source: https://www.youtube.com/watch?v=uENITui5_jU
 
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Mick West

Administrator
Staff member
It's not a special camera. The iPhone can shoot at 24fps. And if you camera shoots at a different speed (like 30), you can just use that tone.

24 is preferred, as you get more movement. But you can use an iPhone for the camera. You could even use it for the tone generator.

It's a popular experiment:
Metabunk 2018-01-26 12-36-22.jpg
 

Mick West

Administrator
Staff member
Here's a high school student discussing how they did it in school:
Source: https://www.youtube.com/watch?v=npw22YDWywg

This was a science project in my school

This effect can't be seen with the naked eye. The effect only works through the camera. However, there is a version of the project you can do where the effect would be visible with the naked eye. For that project, you'd have to use a strobe light.

Run the rubber hose down past the speaker so that the hose touches the speaker. Secure the hose to the speaker with tape. The goal is to make sure the hose is touching the actual speaker so that when the speaker produces sound (vibrates) it will vibrate the hose.

Switch your camera to 24 fps. The higher the shutter speed the better the results. But also keep in the mind that the higher your shutter speed, the more light you need. Run an audio cable from your computer to the speaker. Set your tone generating software to 24hz and hit play. Turn on the water. Now look through the camera and then the water should look frozen. If you want the water to look like it's moving backward set the frequency to 23hz.

If you want to look like it's moving forward in slow motion set it to 25hz.
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(Note: "shutter speed" is a different thing to frequency/fps, lower frequency is still best.)
 

Trailblazer

Moderator
Staff member
Doesn't the wagon wheel effect make true virtual reality impossible?
Not sure what you mean - that the effect lnmoving objects would be a giveaway? I suppose you could work around it by controlling the speed of objects or using motion blur etc.

I've noticed the "wagon wheel" effect with the naked eye before, with no special set-up other than an electric LED light which has a fast flicker due to the AC power supply. The flicker rate is faster (typically 100-120Hz, twice the frequency of the AC supply), so you need a fast-spinning wheel to match the rate.
 
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Ravi

Senior Member.
I've noticed the "wagon wheel" effect with the naked eye before, with no special set-up other than an electric LED light which has a fast flicker due to the AC power supply. The flicker rate is faster (typically 100-120Hz, twice the frequency of the AC supply), so you need a fast-spinning wheel to match the rate.

Interesting you mention that. At work I use a 500Hz image acquisition system and in combination with a LED torch, you can (not naked eye) see the effect of the frequency of the LED in the frames as black, horizontal rectangles moving top down. Bit annoying, as I always need to use incandescent lamps..
 
I suppose I should amend that to recorded media. No matter how fast the frame rate is, a spinning, marked wheel could be timed so it strobed.
 
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However, there is a version of the project you can do where the effect would be visible with the naked eye. For that project, you'd have to use a strobe light.
Content from External Source

I was going to say this isn't new as I saw this water affect on the Don Lane Show here in Australia in the late 70's/early 80's using a strobe light.

These people (geo...) are pathetic.
 

Hevach

Senior Member.
Not sure what you mean - that the effect lnmoving objects would be a giveaway? I suppose you could work around it by controlling the speed of objects or using motion blur etc.
Many video games have motion blur, but there's a cleverer trick with things like wheels and rotors: When they're above a particular speed, switch the texture from the static one to a pre-blurred version. It's less resource intensive than motion blur and doesn't have the unwanted side effect of making rapid twitch camera movements (common in first person games) smear the whole screen, and it handily prevents the wagon wheel effect. Alternately it can build the effect in so it's not ruined by framerate fluctuations, some games use this to make helicopter rotors more visible.

Perfect virtual reality is vastly beyond current technology, but we can already do a pretty good job of faking it with some spit shine on the rough bits.
 

Agent K

Senior Member
There's a toy that uses a strobe light instead of a camera to make water drops appear to levitate or even float upward.

 

Agent K

Senior Member
I suppose I should amend that to recorded media. No matter how fast the frame rate is, a spinning, marked wheel could be timed so it strobed.

It's a general problem of undersampling in time or space, which causes aliasing. It's the same thing that causes Moire patterns in photos of striped shirts, due to insufficient pixel resolution. To prevent it, you need a sampling rate that's twice the highest observed frequency, or you need to perform anti-aliasing that removes the high frequencies by blurring the observed signal before sampling it.
 

Mick West

Administrator
Staff member
To prevent it, you need a sampling rate that's twice the highest observed frequency, or you need to perform anti-aliasing that removes the high frequencies by blurring the observed signal before sampling it.

Or do the blur naturally by having the exposure time (1/24th of a second) match the frequency (24 fps/Hz). That's why the best examples are done in bright sunlight, when the camera is forced to use a very short exposure (1/1000th or so). There's some much less impressive examples done indoors by the less scientific viral video crowd, where you get a kind of "blur with gaps" effect.
Metabunk 2018-01-29 05-34-01.jpg
 
The experiment testing the fidelity of virtual reality video could be done. Set up a room with a window next to a bicycle race then switch between live and recorded views. To move the goal posts, perfectly replicating the experience of skiing suncups in virtual reality looks impossible.
 

Leifer

Senior Member.
...or the videos were shot under a strobe light, which could have a wider frequency range for the same effect (mentioned before) and not reliant on video frame-rate, and therefore observable to the naked eye.
 
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