More hair-splitting.

Sir, how can you argue against what your very eyes see?

Only in the Helmet Thread...

An explosion (of the kind discussed) is nothing but a rapid combustion that involves a sudden rise in temperature, and release of rapidly expanding gases and energy. Look up the definition of "explosion" if you don't believe me.

And that is what the video shows.

When ignited, gasoline, say on the ground, will burn but if confined in a tank it will explode, same as gunpowder burns on the ground but explodes in the barrels of cannon.

One such rapid combustion or explosion is the very basis of the combustion engine. It's so rapid that it occurs thousands of times per minute.

Different substances explode at different rates, gasoline-air and gunpowder not as rapid as dynamite or plastique but the effects are "explosive" nevertheless.

Why do I have to explain this to adults who supposedly went to school?

"What you see there is the liquid being atomized by the rupture, scattered into the air, and a spark happened in a spot where there was the right mixture."

Thank you for making my point. That is called also an exploding motorbike gas tank during a crash, the very point you and some other people seem bent on denying, despite VIDEO FOOTAGE evidence.

The fact that overly rich gas-air mixtures won't ignite has nothing to do with it. Wet gunpower won't ignite either, but sometimes gunpower isn't wet, is it?

It is clear that you don't need a carburetor or fuel injector to get a rupturing gas tank to ignite and explode sometimes, is it not?

Need not take my word for it either, skeptics.

"Low explosives are normally employed as propellants. Included in this group are petroleum products such as propane and gasoline, gunpowder."

"High explosives (HE) are explosive materials that detonate, meaning that the explosive shock front passes through the material at a supersonic speed [...] For instance, TNT has a detonation (burn) rate of approximately 5.8 km/s (19,000 feet per second), [...] and C-4 about 8.5 km/s (29,000 feet per second)"

Do you see the word "explosive" there used for BOTH gasoline and TNT?

https://en.wikipedia.org/wiki/Explos...al#By_velocity

The logic behind their statements that a bare head would not have hit the pavement in a crash is that by some miracle a person not wearing a helmet could somehow slow their bare head within the inch or two of helmet thickness to the point where the head sans helmet would not strike the pavement that a helmeted head did.

IUt;s a specious stance as far as I'm concerned. that's because the momentum required to slam a helmeted head onto pavement is going to be too great for a person to avoid striking their head sans helmet as the momentum is going to be greater that what a distance of a mere inch or two can avoid.

Cheers

I'm not.

My eyes see a FIRE. I see how it starts. Go frame-by-frame and you see that it is on the ground when it ignites, not in the tank.

You might think that I'm splitting hairs, but I'm just not seeing an explosion, and have never seen a gas tank which had exploded as a result of the gasoline inside it.

It does not matter what you have never seen or not seen. I've never seen a thread like this before, and it happens. So much for **** Sapiens.

When you look at the video you SEE a gas tank explode: for the first time in your case.

More here, break a leg...


Can you say Ford Pinto?


The motorcycle race video clearly shows BURNING gas VIOLENTLY EJECTED in an EXPLODING fashion from the exploding tank. It is not spilling and spreading on the ground as liquid and then igniting as you imply.

if you light up a small pool of gasoline it will ignite in place and burn out without covering a bigger area.

If you light up gasoline in a confined space it will explode and eject burning gasoline quite some distance and
very quickly, THAT is what the video shows.

AGAIN: [MY CAPS]

"Under normal conditions, low explosives undergo deflagration at rates that vary from a few centimetres per second to approximately 400 metres per second. IT IS POSSIBLE FOR THEM TO DEFLAGRATE VERY QUICKLY, PRODUCING AND EFFECT SIMILAR TO A DETONATION. THIS CAN HAPPEN UNDER HIGHER PRESSURE OR TEMPERATURE, WHICH USUALLY OCCURS WHEN IGNITED IN A CONFINED SPACE. [...] Included in this group are petroleum products such as propane and GASOLINE."

https://en.wikipedia.org/wiki/Explos...al#By_velocity

If you still can't see it, I recommend you run, don't walk to LensCrafters.

If you say so. It's not worth my time to keep talking about this. Apparently it's important to you that you win, so YOU WIN.

As parting shots go, it's unworthy.

What do you think propels the burning gas SIDEWAYS across the road? It's the explosion of the gas inside the
tank jetting out from apertures in the tank. It's obvious, for Christ's sake.

Stick to helmets.

--------------------------------------------------------------------------------------

The problem isn't what I wrote, it's your reading comprehension. I basically wrote that they were approximately the same, but that there are differences. Ironically you threw the differences I mentioned back in my face, as if it were valid arguments against what I said:

Let me quote, well, me "the latter [...] also tosses a heavy machine into the mix"

me: "the latter often, but not nessesarily happens at a higher speed"
In this case velocity is the more important component of kinetic energy (=the forces involved) anyway. Pro-tip, if you don't know what big words mean, you probably shouldn't use them. Multiple orders of magnitude means at least 2 orders of magnitude, = x 10² = is *at least* 100 times bigger forces in motorcycle crashes. Which perhaps explains the following nonsense since apparently, in your imagination they're all two-wheeled rockets.

The "following nonsense" of course being:

It's not a gas, it's a liquid, it's not explosive, it's flammable. And it's, in case of motorcycles at least, generally near your crotch, not near your chest.

the latter makes this remark unintentionally funny as an extra bonus:

Anyway, others have already addressed your misconceptions about the properties of gasoline,, and while I'm not in anyway an expert, I know enough to know that they based themselves on thing like physics, chemistry and reality. You OTOH seem to think that crashing motor-vehicles often, if not typically, explode on impact, just like in the movies. Even if that was the case, a helmet wouldn't offer much, if any, protection against that, so there's that.

I'm not entirely sure what you're trying to say here.

But then again, bicycle helmets are a compromise between safety on one hand, and comfort, weight, fashion etc. OTOH to the point there's very little safety left. Which would be the central point of my previous post.

Thank you, Cpt. Obvious. But you got a point, I probably shouldn't have used the verb "to guarantee" Weren't you the guy who bored us all with his aversion for "splitting hairs" btw?

Things like "limiting your speed" and "slowing down when approaching intersections" will prevent a lot more injuries than strapping some Styrofoam to your skull. Prevention is key in bicycle safety, something one thinks would be obvious to everyone, if it weren't for all the "I went full ****** on bicycle and AHSML" testimonies.

No doubt wise words, but relevance?

And you are obnoxious, abrasives, arrogant and not bright enough to be aware of your own shortcomings in this discussion, so?

I do not know if the helmet increases the chance the helmet (vs head) of hitting the ground, in real world bicycle crashes for most people. But I can tell you that I will attempt either a forward shoulder roll or a side-fall technique in a bike crash, as I have most of the time in the past. Usually it works, and when done correctly your head doesn't hit. An extra 2 or 3 inches around the head however could result in an impact.

Any studies that show that your hypothetical is a real issue?

Crickets.

Just like the studies of the efficacy of shower helmets?

Crickets.

And stairway helmets.

Crickets.

And pedestrian helmets.

Crickets.

-mr. bill

For a child wearing a heavy, skate-style helmet, I think there is quite a good chance that in a crash the child would be able to avoid a head-to-ground impact better without the helmet than with. Those chances become lesser as neck strength improves and helmets get lighter and any actual impact lesser in degree in turn, but it never goes away. A half pound on your head in the form of a helmet is a half pound more than your neck is used to controlling. Some helmets protrude much more than an 'inch or two' as well.

And what really matters is the torque applied to the head which can happen with even a small impact and some sliding motion. More likely to hit plus more torque applied.

So many weasel words, so few words.


-mr. bill

Throw out 'weasel words' and you might as well burn any study ever conducted on anything. Did you expect that I've conducted a test on this? Or do you need a test to predict what the math says will happen?

You offered a conclusion with ZERO STUDY.

So, knock yourself out. Conduct a study. Report back when you finish your study.

Crickets.

-mr. bill

I suggest some training in forward rolls and side-falls, so that you won't have to guess whether some "studies" are applicable. Knowing something about it would also facilitate presenting an intelligible argument about it, if that's your goal.

The "studies" you seek are embodied by the knowledge of thousands of experts, who teach these techniques on a daily basis. These methods are designed, and proven over centuries, to prevent injury. Especially head injury. You might as well demand a study proving that a man can run 100 yards in 10 seconds.

Any of several martial arts will provide this training, even tae kwon do but better aikido, judo, or something of that nature. Or gymnastics. There are a lot of ways to get those skills, with minor variations. Personally I learned the basics as a young man with stunt-man training, and later learned better techniques in an Aikido dojo.

So your answer is *NO* studies.


-mr. bill

I said 'I think' and provided some commentary to explain my thoughts. You've gone and done some mind-************ with that and come up with your own conclusion which apparently needs 'a study.'

Do accept every conclusion ever offered by 'a study' anyway?

Literally, you're demanding a "Study" proving that a Black Belt in Aikido can execute a fall without hurting his head!

You don't see the absurdity in that?

Literally, I'm demanding a "study" showing that a Black Belt in Aikodo is LESS LIKELY to execute a fall without hurting his head if they are wearing a helmet.

Any other absurd sentences you would like to write?

(There are way too many "maybe the person would get thrown from the car and survive if they weren't wearing a seat belt" nonsense in this thread.)

-mr. bill

No. Do you accept every conclusion that somebody "thought"?

-mr. bill

Of course not. If I'm interested in having an adult conversation I'll offer my own counter thoughts. Perhaps if I've had too much to drink, I'll jump up on the bar and shout 'Prove it!' but I'd like to think I'm beyond those years.

You derived that somehow from "An extra 2 or 3 inches around the head however could result in an impact."

Seriously, I suggest learning more about it before arguing. If executed right, every time, you should have 3 inches of clearance. If you miss a little - it happens - you can have less clearance in the roll. If you happened to back-fall instead of side, chances are fair that you'll hit the helmet.

This is very basic.

"Jonathon Cross" the hero character in Rollerball (2002) wore a Helmet ,

but could never get around to snapping the buckle on the strap..

You can start by throwing out any real-world study on the efficacy of bicycle helmets. You'd be hard-pressed to find any real-world statistics that are worth a flip. The only bicycle crashes that get reported are the ones that have injuries (and probably serious injuries). So the countless times that a cyclist has fallen and their helmet has actually done its job never get calculated into the study. And the even larger number of times that a cyclist has fallen without even striking their head never get calculated either.

Trying to make this a numerically provable argument is quite pointless.

If you were to fall backwards while walking down a sidewalk and struck the back of your head first -- you would probably, perhaps hopefully, be DRT (COP acronym for Dead Right There). If you did not die, you would, at minimum, lead an entirely different life from that time forward. There is little or no doubt about this (do your own google search; I've seen 'it' first-hand). Brain injuries are permanent and usually debilitating.

Y'all can play your one-up semi-intelligent games as you will; doesn't matter --- doesn't mean a thing.

Helmets work. Within their carefully relevant limits. They can and do prevent brain injury in many and perhaps most instances.

I know of what I speak.

Joe

The question is whether riding a bike is within those relevant limits. The assumption that wearing a helmet while riding a bike seems very logical, but is it substantiated at all?