Examples of fast events for normal people - Page 1
Forum section: electronics / general

author: daqq
author_rank: Super Contributor
timestamp: June 20, 2022, 08:58:14 pm
content: 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 athttps://en.wikipedia.org/wiki/Orders_of_magnitude_(time)and most of the things there are hard to relate to for muggles.Thanks,David

author: bdunham7
author_rank: Super Contributor
timestamp: June 20, 2022, 09:05:12 pm
content: 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.

author: james_s
author_rank: Super Contributor
timestamp: June 20, 2022, 09:48:19 pm
content: 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.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: June 20, 2022, 09:55:36 pm
content: 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.

author: Someone
author_rank: Super Contributor
timestamp: June 20, 2022, 10:56:21 pm
content: Quote from: CatalinaWOW on June 20, 2022, 09:55:36 pmCare of the universal student ruler (30cm/12") most people in metric countries still have a common cultural reference for that length.

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 21, 2022, 12:51:56 am
content: 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.

author: jeremy
author_rank: Super Contributor
timestamp: June 21, 2022, 01:25:06 am
content: 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.

author: David Hess
author_rank: Super Contributor
timestamp: June 21, 2022, 01:29:11 am
content: Quote from: CatalinaWOW on June 20, 2022, 09:55:36 pmMy 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.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: June 21, 2022, 02:00:21 am
content: 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.

author: magic
author_rank: Super Contributor
timestamp: June 21, 2022, 06:32:16 am
content: 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.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: June 21, 2022, 06:58:02 am
content: Quote from: NiHaoMike on June 21, 2022, 12:51:56 amI 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.

author: hli
author_rank: Frequent Contributor
timestamp: June 21, 2022, 10:04:41 am
content: Quote from: NiHaoMike on June 21, 2022, 12:51:56 amThat 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)

author: RoGeorge
author_rank: Super Contributor
timestamp: June 21, 2022, 10:30:39 am
content: Quote from: daqq on June 20, 2022, 08:58:14 pmThen youmustshow 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.htmlbut 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.

author: Zero999
author_rank: Super Contributor
timestamp: June 21, 2022, 10:56:46 am
content: Quote from: hli on June 21, 2022, 10:04:41 amIf 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.

author: eugene
author_rank: Frequent Contributor
timestamp: June 21, 2022, 03:33:52 pm
content: 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.

author: HighVoltage
author_rank: Super Contributor
timestamp: June 21, 2022, 03:46:34 pm
content: Quote from: Someone on June 20, 2022, 10:56:21 pm33cm / 13" is more accurate and easier to remember.

author: RoGeorge
author_rank: Super Contributor
timestamp: June 21, 2022, 04:16:06 pm
content: Quote from: eugene on June 21, 2022, 03:33:52 pmOK, 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.

author: Peter Taylor
author_rank: Regular Contributor
timestamp: June 21, 2022, 04:53:50 pm
content: 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.

author: eugene
author_rank: Frequent Contributor
timestamp: June 21, 2022, 05:41:28 pm
content: Quote from: RoGeorge on June 21, 2022, 04:16:06 pmI 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.

author: ebastler
author_rank: Super Contributor
timestamp: June 21, 2022, 05:50:36 pm
content: 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.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: June 21, 2022, 08:09:06 pm
content: 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.

author: daqq
author_rank: Super Contributor
timestamp: June 21, 2022, 08:46:50 pm
content: 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 drawerConcerning 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 worryThanks!

author: jonpaul
author_rank: Super Contributor
timestamp: June 22, 2022, 06:38:28 am
content: Fastest events in Physics are nuclear and thermonuclear devices,1942 paper:https://sgp.fas.org/othergov/doe/lanl/docs1/00349710.pdfBook: The Los Alamos Primer: The First Lectures on How To Build an Atomic Bombhttps://www.amazon.com/Los-Alamos-Primer-Lectures-Atomic/dp/0520075765Serber'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

author: Circlotron
author_rank: Super Contributor
timestamp: June 22, 2022, 08:09:36 am
content: Quote from: daqq on June 20, 2022, 08:58:14 pmThe time it takes some people I know to zone out once I start talking tech.

author: tszaboo
author_rank: Super Contributor
timestamp: June 22, 2022, 08:43:17 am
content: 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.

author: RoGeorge
author_rank: Super Contributor
timestamp: June 22, 2022, 10:28:11 am
content: Quote from: daqq on June 21, 2022, 08:46:50 pmThat's a good analogy, thought it's rather 30 years than 100. An average century is 3,155,695,200 seconds, briefly said π∗109.Another funny one about "nano", hair grows about 4nm each second, and having to wait till it grows 4m long...

author: Peter Taylor
author_rank: Regular Contributor
timestamp: June 23, 2022, 10:42:45 am
content: My hair is very long. It took a very long time to grow it; using the hair analogy.

author: SiliconWizard
author_rank: Super Contributor
timestamp: June 24, 2022, 12:17:54 am
content: Should be fun looking at hair growing in almost "real time" using an electron microscope.

author: ve7xen
author_rank: Super Contributor
timestamp: June 24, 2022, 12:40:47 am
content: Quote from: CatalinaWOW on June 21, 2022, 08:09:06 pmCounterpoint - quartz oscillators and SAW filters are built well into the 100s of MHz, and are based on a (fairly) macro physical phenomenon. Similarly, there are also MEMS devices that operate in the MHz. I find this pretty crazy, myself.I think audio does an alright job of bridging this gap, in the context of scopes. Most people have a reasonable fundamental understanding of sound and how quickly the waves are alternating from their experiences with low frequency sound, and at high-ish frequencies, it's below 1ms. Something like playing a 50Hz sound and showing the waveform at a human-ish timescale (maybe like 0.5s across the screen), then ramping that up until it's unintelligible on screen, and zooming back in can get the 'point' across.Examples based on the speed of light 'an ns per ft' do more to drive home how fast the speed of light really is, but not sure they help understanding time. As far as we experience in our daily lives, the speed of light may as well be infinite. So it's impressive that a scope can measure it, but doesn't really connect with intuitive understanding, I reckon.

author: RJSV
author_rank: Super Contributor
timestamp: June 24, 2022, 11:30:43 pm
content: A musical and audio science background helps. Maybe you could say as an example, of two different realms, the first being around 30 milliseconds. That, at speed of sound, represents a moderate distance.Going smaller, relative to 30 mSec, try and explain that slap-back sound (see title Rock Roll Music, 1970s).Explain the Slap-back starts to get smaller than perception, at a few mSec. A 'quick' hands together slap could take 40 to 100 mSec.Explain that those example, speed of sound, use approx 980 ft per sec, or a bit slower, than 1 mSec so, a bit less than 1 foot in a 1 mSec time.THEN, you explain, you want to relate that (speed) to electrical 'speed', ...at approx. 1.5 BILLION TIMEs faster.Heck, at that point, I'd lay it all out, onto the (desk) of the listener. "Tell you what..." you'd say:"Can anybody here relate, that 1.5 BILLION difference in rates of travel, between light/radio waves, and acoustic waves here at sea level?"In other words, let the STUDENTs struggle, to explain, to the less advanced, what is 1.5 Billion times factor different... The ideas, of vastly different quantify-able speeds, almost supercedes the topic...lol

author: Sredni
author_rank: Frequent Contributor
timestamp: June 26, 2022, 10:15:45 am
content: Quote from: Peter Taylor on June 21, 2022, 04:53:50 pmI thought there were six of those:DefineDesignDevelopDeployDespairDelegate or DestroyFor the OPMake a wooden 'square wave replica' 10 cm long (or one foot long)Then put your hands at the beginning and end of it and tell your audience: "If this was a millisecond period, in a second there would be a thousand of these replicas, and the duration of a second would be represented by a chain of these replicas 100 meters (or a thousand feet, or whatever) long. And if this was a microsecond, a second would be a 100 km long string of these replicas. If this was a nanosecond, the string of this replica fitting in the 'length of a second' would be a hundred thousand km long."Then you can apply the televisionification of units: 100 mt is one football stadium, while 100 km is the distance between two main cities in your area or Country, and 100 thousand km is two and a half time the circumference of the Earth.Now, show some respect for that runt search function in your oscilloscope!!!(check the numbers, I might be off by an order of magnitude or two, no big deal)

author: ebastler
author_rank: Super Contributor
timestamp: June 26, 2022, 11:01:32 am
content: Quote from: Sredni on June 26, 2022, 10:15:45 amI am not sure this would work for "normal" people. Switching back and forth between times and lengths to illustrate things does get a bit confusing:Why would a time be represented by a length? Why would either be represented by a square wave? And I don't think you can take it for granted that people find the rule of three intuitive at all...

author: Sredni
author_rank: Frequent Contributor
timestamp: June 26, 2022, 12:06:47 pm
content: Quote from: ebastler on June 26, 2022, 11:01:32 amWell, is it not already represented by a length on the screen of the oscilloscope? You count the divisions, by what you are really counting is how long the signal is represented on the screen.The advantage of using a 10 cm wooden square wave is that it can be superposed on the same size square wave on the screen of the oscilloscope.First you give something material, to which the audience can relate - a piece of wood they can hold in their hands. Then you draw the parallel with what they see on the scope's screen. The time scale is... in space after all.And then you can put a 1ms period wave on the screen and repeat the concept: if I wanted to see an entire second on this timescale, the oscilloscope screen should be 100 meters wide.QuoteIt's easier to build :-) and in my opinion it relates better to the idea of clock signal.QuoteI had to look it up what the rule of three was. I don't see the relevance with what I wrote. It's because I made three numerical examples?