Saving my pennies for Chronos 1.4 High-speed Camera

[Andy Resnick]

Wasn't sure where to post this, but since I'd likely use it for classroom videos:

https://www.kickstarter.com/projects/1714585446/chronos-14-high-speed-camera/description
http://www.krontech.ca/uploads/9/3/8/3/93836312/chronos_1.4_datasheet.pdf

Let's hear some ideas (besides the tried-n-true obvious ones: collisions, bursting balloons, water drops...). The combustion videos (in the "Bullet Time" video) are interesting but uncontrolled. Electrical sparks/ lightning? Glass fracture?

 

[OmCheeto]

Not sure if it's possible with your 'future' camera, but Prof Poliakoff and I are curious why exploding hydrogen balloons look red.



My idea: put a diffraction grating thingy on your camera, and determine the temperatures.

 

[mfb]

Looks more yellow to me.

 

[OmCheeto]

Looks more yellow to me.

It might have been the "blink" factor, that threw his color scale off.

Looks red to me.

 

[mfb]

Ah missed that one. There are so many of them.

 

[Dr. Courtney]

With some care, you can use it to study deflagration rates in fuel-air and fuel oxy mixtures. We bought a roll of 1" diameter thin film tubing for this. It worked well. See: http://chemeducator.org/bibs/0016001/16110279.htm

Mostly, we've used a camera with comparable frame rates for bullet impacts into ballistic gelatin, handgun recoil, and muzzle flash. Great tool for that.

In an intro physics class, I'd used it to quantify delta T in momentum impulse problems to verify that the computed estimate for the duration is about right. The difference in delta T for different bouncing balls is quite telling. Coupled with a Vernier force plate, you can have two perspectives on bounces.

We've been toying with using one either for precise g measurements (using Tracker) and/or drag coefficient measurements. You can get a pretty decent g measurement (< 1%) with care and a 30-60 fps camera. Get a situation where you can ignore air resistance and fit the tracker curve, y(t), to a parabola with 10,000 data points (frames), odds are you can get at least three significant figures on g. (Use Tracker).

 

[Dr. Courtney]

This picture shows a sequence of frames at 10000 fps and comparable resolution to the Chronos. The study design actually focuses on handgun recoil, and the position vs time is established with Tracker. The cartridge is 40 S&W. Differences in recoil and muzzle flash are easily documented with the high speed video.

 

[Andy Resnick]

<snip>
In an intro physics class, I'd used it to quantify delta T in momentum impulse problems to verify that the computed estimate for the duration is about right. The difference in delta T for different bouncing balls is quite telling.
<snip>

Like!

 

[Andy Resnick]

<snip>My idea: put a diffraction grating thingy on your camera, and determine the temperatures.

Interesting idea! Don't know if the optical throughput will be high enough, tho... could potentially look at sonoluminescence or triboluminescence as well.

 

[Dr. Courtney]

Not sure if it's possible with your 'future' camera, but Prof Poliakoff and I are curious why exploding hydrogen balloons look red.

My idea: put a diffraction grating thingy on your camera, and determine the temperatures.

We've thought about how to estimate temperatures of fast deflagrations with the high speed camera. The spatial extent of most reactions makes this challenging, and the usual approach to using a slit sacrifices too much light (fast photosensors need a lot of light and sensitivity drops in the IR and even the near red on some.) I think the approach most likely to work to estimate temperatures would be to repeat the high speed video with different (relatively narrow) color filters, correct for the frequency sensitivity of the detector, and estimate the temperature from the intensity ratios through the different filters. It is not a trivial problem. (You're essentially trying to make a fast thermal imager.)

 

[OmCheeto]

We've thought about how to estimate temperatures of fast deflagrations with the high speed camera. The spatial extent of most reactions makes this challenging, and the usual approach to using a slit sacrifices too much light (fast photosensors need a lot of light and sensitivity drops in the IR and even the near red on some.) I think the approach most likely to work to estimate temperatures would be to repeat the high speed video with different (relatively narrow) color filters, correct for the frequency sensitivity of the detector, and estimate the temperature from the intensity ratios through the different filters.

Sounds expensive. Maybe I'll just do some maths, and study some more.

It is not a trivial problem. (You're essentially trying to make a fast thermal imager.)

This is why I handed the problem over to Andy!

I did a bunch of experiments yesterday, and based on the results, have decided to rescind my request.

The results of my experiments, in visual form:

Anyways, I'll try and think up some more "hi-speed" experiments.