Examples of fast events for normal people

[daqq]

Hello,

I am doing a presentation on oscilloscopes. Some of the people will not be very technically oriented or at least may have some trouble relating to things like nanoseconds or GHz. Most of the people will be programmers and embedded firmware developers, but there will also be some less electrotechnical/science oriented people present and I want them to get something out of it as well.

In a previous presentation involving measurement resolution I used a simple table where there was a weighing scale with a 10 ton range and 5 ton elephant on it connected to a voltmeter with a 3.5 to 8.5 digit resolution. For each of the resolutions I listed what could be counted using the meter - with a 3.5 digits you could count the number of dogs sitting next to the elephant, for 8.5 digits of resolution you could guess at the number of tens of flies sitting on the elephant. It was an oversimplification, got a bit slightly wrong but it made the whole thing more relatable, got some positive feedback for it.

I would like to do something similar for the sampling speed/bandwidth of oscilloscopes - basically tell what's the shortest event that they can capture (with lots of assumptions) in a normal human relatable manner. Milliseconds are reasonably doable and relatable, say, the time it takes a bullet to pass half a meter or that a sports car only moves by thiiiis tiny bit during this time. But the smaller the times get, the more I'd need to reference more hard to relate concepts (speed of light, wave propagation and similar).

I want to avoid just saying that "look! A is soooo small, now B... it's like a thousand times smaller!" or use the old trick of trying to awe the audience with a long string of zeros in front of a number.

Do you have any relatable events that take a millisecond, microsecond, nanosecond or somewhere in that area? Doesn't have to be exactly a nanosecond, 3.512 nanoseconds will do just fine. Or how would you go about illustrating to the non-technical people such things?

I've looked at https://en.wikipedia.org/wiki/Orders_of_magnitude_(time) and most of the things there are hard to relate to for muggles.

Thanks,

David

[bdunham7]

It takes about 10 ns for the signal to run the length of the probe cable.   But perhaps comparisons to time would work better?  300ps is to one second as one second is to a century, something like that.

[james_s]

Maybe a TDR demonstration? You can quite accurately measure the length of a cable by measuring the time it takes for a pulse to reflect off the other end, but if you were to for example connect an LED to one end and a battery to the other, a human would perceive the LED as responding instantly even if the cable was miles long.

[CatalinaWOW]

Grace Hopper's example, that a nanosecond is a foot works well in places that remember traditional units.  The metric equivalent is technically sound, but doesn't have quite the panache.

In general distances and light speed work well.  Even though most people have no real grasp of the diameter of an atom or the size of a FET gate they can relate to them.

[Someone]

Grace Hopper's example, that a nanosecond is a foot works well in places that remember traditional units.  The metric equivalent is technically sound, but doesn't have quite the panache.

Care of the universal student ruler (30cm/12") most people in metric countries still have a common cultural reference for that length.

[NiHaoMike]

One very famous example would be Michael Phelps winning by 1/100th of a second. But on a scope, 10ms is a very long time...

I suppose a good demo would be a pulsing laser bouncing off a mirror and then hitting a detector, to explain how LIDAR works by observing the delay as the distance to the mirror is changed. Could also do something similar with a speaker and microphone, to show the difference in speed of sound vs speed of light.

[jeremy]

I think that most people know that animations or movies are based on frames in the order of 20-60 fps.

I also think maybe slow motion footage of things may be useful, for example, showing 50Hz lighting flicker, showing a helicopter in slow motion, a bullet hitting ballistics gel/glass/fruit or an explosion. The YouTube channel “The Slow mo guys” has a lot of stuff on this; you could argue that they have this problem every single video where they need to explain short timescales to a general audience.

[David Hess]

Grace Hopper's example, that a nanosecond is a foot works well in places that remember traditional units.  The metric equivalent is technically sound, but doesn't have quite the panache.

My standard is 85 picoseconds per inch because that is where things get really interesting.  The problem is that few people have a sense of scale of nanoseconds let alone picoseconds.

The speed of sound would be a good reference since a person can observe it directly.  1100 feet per second yields about 1 millisecond per foot.

[Ed.Kloonk]

A youtuber, David Bennett Piano, put out a long, cracker of a video a few days ago regarding music theory.

In it, there is an interesting take on pitch perception.

[magic]

Show them FS USB signals with and without 20MHz limit, then HS or SS if you can.
These are fairly fast events that embedded developers might be somewhat familiar with.

[chickenHeadKnob]

One very famous example would be Michael Phelps winning by 1/100th of a second. But on a scope, 10ms is a very long time...

I suppose a good demo would be a pulsing laser bouncing off a mirror and then hitting a detector, to explain how LIDAR works by observing the delay as the distance to the mirror is changed. Could also do something similar with a speaker and microphone, to show the difference in speed of sound vs speed of light.

I was thinking of Olympic touch pads and time resolution and the "key debounce problem". I would show a capture of  typical unfiltered raw button press and then explain that everytime they are typing on a computer keyboard multiple edges are occurring and that the micro in the keyboard is filtering those out. The same happens for aquatic sports touch pads, increasing the possibility of a tie being recorded.   

[hli]

One very famous example would be Michael Phelps winning by 1/100th of a second. But on a scope, 10ms is a very long time...

That reminds me: in the 'German Sport and Olympics Museum' (in Cologne), to explain how close this race was, there are two buttons next to each other. You task is to press them, one after the other, and get a time difference of just 1/100th of a second between the presses. (I think I came down to 6 or 7 hundredths of a second, but not better)

[RoGeorge]

Most of the people will be programmers

Then you must show them what 1ns is, vs 1 microsecond, this style:



Good programmers will already be aware of visual representations of time scales from other places similar with this:
https://colin-scott.github.io/personal_website/research/interactive_latency.html
but I think the physical piece of a "1ns wire", vs a spool of "1us wire", has more impact than any chart.  You can pass them the wires, so they can touch and feel their weight while passing the two from one to another.

[Zero999]

One very famous example would be Michael Phelps winning by 1/100th of a second. But on a scope, 10ms is a very long time...

That reminds me: in the 'German Sport and Olympics Museum' (in Cologne), to explain how close this race was, there are two buttons next to each other. You task is to press them, one after the other, and get a time difference of just 1/100th of a second between the presses. (I think I came down to 6 or 7 hundredths of a second, but not better)

If the time difference between two runners is under 50ms, then it's as good as a draw.

I had a stopwatch with a resolution of 0.01s as a child. If I pressed the start/stop button twice very quickly, I could get it to stop at 0.03s. I thought it was pointless having such a high resolution. 0.1s, would have been more than good enough. The extra digit made no difference, given the human is the weakest link.

[eugene]

I'm certain that if I were giving the talk (on oscilloscopes) I would share the entire Grace Hopper video, just because everyone should know who Grace Hopper was and get a chance to see her.

[HighVoltage]

 (30cm/12") most people in metric countries still have a common cultural reference for that length.

33cm / 13" is more accurate and easier to remember.

[RoGeorge]

I'm certain that if I were giving the talk (on oscilloscopes) I would share the entire Grace Hopper video, just because everyone should know who Grace Hopper was and get a chance to see her.

OK, but wrong reasons.  A video is supposed to be watched for its good content, not for the fame of who's in it.  You see, if you share that video for the reasons you stated, than that's just a shameless propaganda plug.  If you share the same video for what she's teaching, that would be fair for everybody.

Maybe I'm too sensitive to nuances, but beware of propaganda and mind conditioning.  That can take over people's behavior without them even noticing their mind was heavily pruned.  Seen that before in the communist eastern world, and seeing it again recently, in the capitalist western world.  It is happening at alarmingly high levels.

[Peter Taylor]

The three D's of engineering. Define, Define, Define.
Define a perfect square wave in theory, then define the imperfect square wave in practice in relation to this.
An oscilloscope, and the circuit it is measuring, aren't perfect.
Define how close to perfect you want the signal to be, then define how closely you want the oscilloscope to show that signal, then define how closely you want that oscilloscope to show a perfect square wave, then see how close to perfect you can get.

It's like building an oscilloscope to measure the rise time of a circuit; that uses that circuit.

[eugene]

I'm certain that if I were giving the talk (on oscilloscopes) I would share the entire Grace Hopper video, just because everyone should know who Grace Hopper was and get a chance to see her.

OK, but wrong reasons.  A video is supposed to be watched for its good content, not for the fame of who's in it.  You see, if you share that video for the reasons you stated, than that's just a shameless propaganda plug.  If you share the same video for what she's teaching, that would be fair for everybody.

Maybe I'm too sensitive to nuances, but beware of propaganda and mind conditioning.  That can take over people's behavior without them even noticing their mind was heavily pruned.  Seen that before in the communist eastern world, and seeing it again recently, in the capitalist western world.  It is happening at alarmingly high levels.

I thought it would be obvious that I also think the video has content that is worth watching and is relevant to the subject. I mean, you don't really believe that I would show irrelevant or worthless video just because I admire the people in it, do you?

In any case, Grace Hopper is an important figure in the history of computer science. Sharing real history cannot be considered propaganda, at least not in my perspective. Not sure how you could see it that way.

[ebastler]

Seems that all of the examples in the sub-millisecond time range have been based on the propagation speed of light or electrical signals. And I can't come up either with something in the domain of mechanics, acoustics or such which would be relatable to the layperson, and happen on µs timescales or faster.

Maybe TV images can provide some "tangible" example numbers: The time it takes to transmit a picture frame (~ 10ms), a single line in the picture (~ 10 µs), and a single pixel (~ 5ns), all for a 1080p full HD image.

[CatalinaWOW]

The explosion front for even fast high explosives only travels a few thousand meters per second, so even the fastest physical events can't get far into the sub-millisecond time frame.  And even that has the flaw that few people are really familiar with this type of event.

I think we are stuck with EM wave propagation for really short time intervals.

[daqq]

Thanks for the discussion and ideas!

I like the "one nanosecond is to a second what a second is to a century"* approach - basically upscale it into something relatable and compare it with something really huge that's relatable. Might work nicely.

Handing out bits of wire to people and telling them that that is a nanosecond is actually a good idea as well! Everyone should have a nanosecond in their drawer

Concerning other examples, yeah, it seems that sub-millisecond things are simply not that relatable to laypeople. I'll probably use the speed of light for some of the really fast stuff.


* - I'll use the proper numbers, don't worry

Thanks!

[jonpaul]

Fastest events in Physics are nuclear and thermonuclear devices,

1942 paper:
https://sgp.fas.org/othergov/doe/lanl/docs1/00349710.pdf

Book: The Los Alamos Primer: The First Lectures on How To Build an Atomic Bomb
https://www.amazon.com/Los-Alamos-Primer-Lectures-Atomic/dp/0520075765

Serber's incredible hand drawn diagram below, is the log of  energy, neutron flux,  pressure  over   time  with  10 exp 30 log scale covering pS to minutes.

From an Optimist in the Nuclear Age!

Jon

[Circlotron]

Do you have any relatable events that take a millisecond, microsecond, nanosecond or somewhere in that area?

The time it takes some people I know to zone out once I start talking tech. 

[tszaboo]

In my hometown they had scaled solar system with some statues. The Sun was like a 400mm ball, Earth was a few mm and I think they only could go to Saturn, which was on the other side of town, a few KM away. That really put things in perspective.

Fast would be to go the thickness of the human hair on the highway with your car (~GHz ?).

That reminds me, I had a colleague, who made everything technical into a car analogy. I told him to stop doing that, because I actually understand how the electronics works better than how my car works.