Fun for nerds

[T3sl4co1l]

I know water, too, can be shaped with high voltage (electrowetting).  Makes me wonder if water can be piezoelectric, too.   

If so, might explain why a hit in the head can knock out one unconscious:  it's the electric shock generated by the piezo-water inside the brain. 

There was someone making electrically-controlled focus-tunable lenses, where the focal distance of a single lens was controlled by a voltage, no motors, based on electrowetting.  Thought his electro-lenses were oil based IIRC, a French guy some 10 years ago or so.

But that's a surface effect -- not bulk.  Field strength modifying surface tension at the boundary makes sense.  (Most dramatic example: alkali metals apparently explode with a transitional hedgehog state, massively increasing the surface area in an instant!)  Or even more mundane: force deflecting an elastic diaphragm; a condenser mic (or the inverse).

Bulk doesn't make much sense, because both the force and the charge can just redistribute.  Or it ain't a liquid!

I suspect they've got some kind of gel phase, or something rheology, or maybe liquid crystal something, going on, so it's sorta liquid but not; or it's a dynamic effect, and only works on time scales above the dipole relaxation rate (which happens to be unusually low in the material, at the temperature tested).  But the article doesn't really say anything about that...

Tim

[Nominal Animal]

Makes me wonder if water can be piezoelectric, too.

Snowflakes are triboelectric.

If so, might explain why a hit in the head can knock out one unconscious:  it's the electric shock generated by the piezo-water inside the brain. 

No, it's typically the brain hitting the skull knocking neurons off-kilter, with unconsciousness resulting from the brain shutting down unnecessary operation to protect itself.

Besides, while cerebrospinal fluid is 99% water, it has a lot of other stuff too.  Its properties differ quite a bit from water.

[RoGeorge]

Indeed, we are more like walking bags of seawater. 
Stepped out of the oceans once, wondering on land since.

[NiHaoMike]

No, it's typically the brain hitting the skull knocking neurons off-kilter, with unconsciousness resulting from the brain shutting down unnecessary operation to protect itself.

Besides, while cerebrospinal fluid is 99% water, it has a lot of other stuff too.  Its properties differ quite a bit from water.

Handegg (incorrectly called "football" in the US) is under criticism for causing brain damage.

[Nominal Animal]

No, it's typically the brain hitting the skull knocking neurons off-kilter, with unconsciousness resulting from the brain shutting down unnecessary operation to protect itself.

Besides, while cerebrospinal fluid is 99% water, it has a lot of other stuff too.  Its properties differ quite a bit from water.

Handegg (incorrectly called "football" in the US) is under criticism for causing brain damage.

The density of the cerebrospinal fluid is such that the brain is very close to neutrally buoyant, i.e. "weightless" within our skulls.  It really cannot support even its own weight without the fluid; and overpressure is similarly deadly.  Trepanation is one of the oldest surgeries known from prehistoric findings, and skulls that show significant healing (years, even decades) after trepanation are not rare.  There is sufficient evidence and historical record to show that this was not a religious practice, but a therapeutic one, applied to specific types of head wounds.

There are brain specialists who believe boxing with gloves is more dangerous to humans than barehanded boxing, because the gloves let humans hit much harder than they can barehanded.  It would be interesting to compare handegg and rugby statistics, as the difference is somewhat similar.

Falling on your face or back on sand or grass is unlikely to do much damage (unless you twist your limb or fall on top of something), but falling on concrete or asphalt and hitting your head can easily kill you.  The exact acceleration profile matters; it is not a total energy or momentum transfer thing.

[RoGeorge]

Have had a former rugby player as a coworker at some point.  He told us it's even tougher than it seems.

The impact from falling is not the worst, from what told us once at a beer.  During a fall, there still is plenty of time to react.  The worst are those actions you don't have time to react.  For example, he was telling how an action as simple as grabbing one's arm while running from opposite directions can have a tremendous impact.  The initiator knows what action will perform next and prepares for it, while the other dude don't.  The effect is that there is no time to react, the body turns from the momentum of grabbing, then suddenly stops.  My understanding was that the effect of such a grab would be similar with that seen in the tip of a whip.  He said he would prefer a hit in the face in a fist fight, rather than that shock that propagates through the entire body during an unforeseen grab at rugby.

[RoGeorge]

The Wooden Transistor 


Source:  Electrical current modulation in wood electrochemical transistor
https://www.pnas.org/doi/10.1073/pnas.2218380120

[RoGeorge]

How Many Legs Are Best?
Curious Archive



 

[RoGeorge]

Hilariously Inaccurate Medieval Art of Animals
Curious Archive



 

[RoGeorge]

Encyclopedia Of A World That Doesn’t Exist | Codex Seraphinianus
Curious Archive



 

[RoGeorge]

The Steam Turbine: The Surprising Relationship of Engineering & Science
engineerguy



 

[RoGeorge]

Smith Chart
TheSiGuy



Every video from this channel is a masterpiece in visualization. 

[RoGeorge]

Bjt Transconductance and small signal model explained visually
TheSiGuy



 

[RoGeorge]

Why Lightbulbs Might Be The Best Idea Ever
Veritasium



 

[RoGeorge]

Euler's Formula Beyond Complex Numbers
Morphocular



     <---   yes, rotations 

[RoGeorge]

How Kodak Punches 384000 HOLES A MINUTE in Film Stock (Kodak Factory Tour Part 3 of 3) - Smarter Every Day 286
SmarterEveryDay


 

The other two parts of the factory tour:
How Does Kodak Make Film? (Kodak Factory Tour Part 1 of 3) - Smarter Every Day 271
How Does Kodak Make Film? (Kodak Factory Tour Part 2 of 3) - Smarter Every Day 275

[RoGeorge]

What is the Riemann Hypothesis REALLY about?
HexagonVideos



 

[RoGeorge]

The Fastest Maze-Solving Competition On Earth
Veritasium



 

[RoGeorge]

Radio Antenna Fundamentals Part 1 1947
Gerry Trenwith



 

Radio Antenna Fundamentals - Part 2 1947

[RoGeorge]

The Largest Civilization in The World
ReYOUniverse



 

[RoGeorge]

A Tesla coil with only three components!
William Fraser



 

[Infraviolet]

Does that count as a Tesla coil? It doesn't seem to be generating any arcs.

[RoGeorge]

Yea, doesn't shoot sparks, maybe in the dark, with a very thin sharpen end loose wire, IDK. 
Still cool that it needs an "EMP" to crank-start it, though. 

[RoGeorge]

This Mysterious Globe Perpetually Spins With No Batteries
The Action Lab



 

[RoGeorge]

Here's a Question! - Why Does the Water Rise?
Jefferson Lab