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  • So today I am going to do everyone’s favorite non Newtonian experiment.

  • I am going to put this corn starch and water solution on this speaker, but I want to do

  • this scientifically.

  • So I am shooting it with a high speed camera and I am going to vary the frequency and the

  • amplitude and see what factors really give us the best corn starch monster.

  • It still very much looks like a liquid at this point, but as I increase the amplitude,

  • you can kind of tell that it is not moving as smoothing as it should anymore.

  • You can see at this amplitude it starts to jump around a little bit.

  • Now I want to try to increase the frequency and

  • see what effect that has.

  • You are now at about 20 hertz, which is the frequency recommended by some scientific papers

  • that have studied this phenomenon.

  • I’ll up the amplitude a little bit.

  • That is incredible.

  • That is awesome.

  • Now I am going up to about 22 hertz, seeing nicer structures.

  • But it is really tough to tell, because it is somewhat random.

  • Sometimes it just turns into a blob like that and other times you get some really cool things

  • forming.

  • I am about 34 hertz here and we are not seeing a lot of structure.

  • It seems like at these higher frequencies it just sort of turns into a blob.

  • Interesting how it becomes more coherent and smoother actually at the higher frequencies.

  • Wow.

  • That’s interesting.

  • In the high speed you can clearly see that the inertia of the thing is keeping it off

  • the speaker entirely.

  • That is really cool.

  • So it is just getting kind of bumped with that frequency.

  • It is not really sticking around.

  • That this why you probably need a lower frequency.

  • Oh.

  • Well, that is the end of that.

  • So how do non Newtonian fluids work?

  • Well, the corn starch and water is really a suspension.

  • That is, these tiny little grains of starch suspended in water.

  • So when you try to move that fluid slowly the starch has time to get out of the way

  • of each other, because it is lubricated by all those water molecules in between.

  • But if you try to get it to go fastand that is, there is a lot of sheer, which means

  • there are some places that are going faster than otherswell, then all of the starch

  • grains kind of get stuck up against each other.

  • And they can’t flow past each other.

  • So at that point it becomes like a solid and less like a liquid.

  • You know, this kind of reminds me of traffic in LA where I have been recently.

  • If there are not that many cars on the road it is basically like having a small amount

  • of starch particles in your water and everything flows very smoothly, but as soon as you get

  • to rush hour and you have some cars which are trying to floor I down the highway, plus

  • there is all of these cars, which are like our starch particles, on the high way, then

  • suddenly everything gets clogged and you are basically in what is a solid.

  • So traffic might be an example of something that is an non Newtonian fluid.

  • It flows very well when there aren’t very many particles or when it is going quite slowly,

  • but as you try to increase the number of cars and go really fast, then everything kind of

  • gets clogged up.

So today I am going to do everyone’s favorite non Newtonian experiment.


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B2 中高級

揚聲器上的慢速非牛頓流體。 (Slow-Mo Non-Newtonian Fluid on a Speaker)

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    林宜悉 發佈於 2021 年 01 月 14 日