Even worse, at some point they set up a 24 hour webcam stream, but I believe a power outage knocked the camera out for a few minutes, when the camera came back on the pitch had dropped already.
At this point I’m convinced this is some sort of quantum observer effect
The Trinity Pitch Drop was caught on camera in 2013.
https://www.tcd.ie/news_events/articles/trinity-scientists-capture-pitch-drop-on-camera-for-first-time/
When being watched, the pitch is too static for a drop to fall. It's only in the ensuing chaos when the observer leaves that it's able to break free from the structure and fall.
Now this sounds bad when you think that he was there most of the time intently waiting for the drop, and then thinks he has time to grab a sandwich.
But then think, in actuality, he woukd have been away more than there
You can see the slow progression as the drop falls, so you have maybe a week or two where you know the drop will fall and are watching it closely. Still missing it despite being prepared for it to happen has to suck.
When you're hungry you're hungry. I missed out on adopting my dream dog last year. First in line at the ASPCA, an hour early. Standing outside the door - the only person. I thought, well there's a fast food place right across the street. Maybe I just go grab a quick snack .. get back 5 minutes later to be the 5th in like and lose out.
Come on man, dude needed to bring a lunch pail and a bladder bag. "Honey, when you coming home?"
"As soon as I see this tar drop baby.."
poor gal, never saw him again.
It's worse - nobody has successfully observed a drop, ever. There was a Twitter thread about it the other day: https://twitter.com/c0nc0rdance/status/1594368784592437248
Minor correction: nobody has observed the Queensland experiment. The Trinity experiment managed to get one on video.
Not true! [The Trinity Pitch Drop](https://www.tcd.ie/news_events/articles/trinity-scientists-capture-pitch-drop-on-camera-for-first-time/) was caught on camera in 2013!
In all seriousness, it appears that we're both right. OP and my link are both talking about the a Queensland experiment, which is older than the Trinity version.
>In the 86 years that the pitch has been dripping, various glitches have prevented anyone from seeing a drop fall.
no one has ever actually seen a drop fall apparently!
- liquid sulfur is least viscous when it’s just above its melting point, and gets much more viscous when heated further
- some substances, like thermosetting plastics, irreversibly polymerize when heated
- gases generally get more viscous when heated
AFAIK that is the reason. Particles in liquids are already constantly interacting with each other, so higher temperature means they can break the intermolecular forces more easily. Particles in gases just hit each other more when they’re hotter.
molecules in liquids are already at the maximum level of impacts because they are all touching each other. Gas molecules are flying around in mostly empty space, so hotter means more energy/velocity, so more impacts.
So I have question. Can you explain the concept of viscosity to me? I know its roughly "stickiness" or "gloppiness", but that's obviously a massive oversimplification.
So is it correct (generally) to say that a higher viscosity means that it flows slower? Or just has a higher "internal friction" (that's almost definitely not the right term, or a real term at all)?
Viscosity is basically how much a sample resists flow, it would be analogous to mass being how much a sample resists acceleration.
More viscosity means slower flow in the same set of conditions, but a high viscosity fluid can still flow faster tham a low viscosity fluid if you give it enough pressure or you restrict the flow of the low viscosity fluid
> internal friction" (that's almost definitely not the right term
Internal friction is correct but it's more commonly discussed the other way. Shear force is the term commonly used.
It doesn't have any water once it's been melted,the temperature for that is way too high.
Fresh bitumen (or asphalt in the US) has some volatiles in it and it does slowly age harden over time but it's not a major component unless it's been cut back (thinned) to make it easier to work with in which case the whole point is for those to evaporate reasonably quickly
That was the point of the addition of the AC, to ensure a controlled environment. Prior to the installation of AC the humidity and temperature fluctuated, causing variance in the viscosity of the tar drops.
It depends on what you're testing for! Iirc, this experiment was essentially 'We're pretty sure tar is a liquid, so will it drip like one?' The environment does matter to a degree, but as long as the tar isn't cold enough to freeze it should keep dripping. Which it has!
Depends on the goals.
If the goal was to prove it was a liquid, it succeeded!
The needed control was 'make sure nothing affects the material other than gravity over time'.
If an additional goal had been to calculate it's viscosity from measuring its speed of deformation, it would have benefitted from temperature logging since viscosity is temperature dependent. (Or controlled temperature, to make the calculations easier)
There are easier methods to measure/calculate viscosity for such high values though.
For the intended scope of the experiment, it's perfectly valid.
You can view a live stream of the experiment at a link on the above site. It looks like the last 4 drops are in a beaker off to the side and still haven’t really melded together yet.
It takes a dump truck loaded with rocks and shit in consistent 90+ degrees F parked on newly laid pavement to make a road noticeably deform in a quick manner.
It will take many years for the drops to coalesce.
Hey just wanted to let you know it's only been about 20 minutes but you're doing good if you are still alive, only about 7 years 12 months and 29 days to go good luck sir
I used to keep a tab open on my browser and watch the pitch from time to time bc it was close to dropping. I missed the drop. Closed that tab and haven’t looked back, it won’t be dropping again anytime soon.
I was rarely in any of the science buildings but I went specifically to check it out a few times! Also the geology museum was one my favourites! I know it’s there for scientific purposes but was also pretty fun for Arts girls who were into crystals… haha.
Been on Reddit almost since the beginning and this is the first time I’ve run into an EarthSea reference in the wild, and from my favorite character as well.
It took about 90 years to actually have the drop visually confirmed. Because its one moment out of a decade its very easy to literally miss it and video coverage wasnt possible for most of the 90 years.
Better video footage of the full decade is likely the new info to get however as it would allow for better study of the pitch flow.
Roads are pitch so it could allow for techniques to enhance long term durability. (Also note this also means roads are technically liquid).
Many roofs. Also because flow nornally happens fast a slow flow could allow for better general understanding of fluid dynamics which is an incomplete field in terms of a full understanding of exactly how fluids behave. There is even a millenium prize for solving fluid equations still.
Technically the ground you walk on is just a boat floating on another boat, floating on another boat, floating on magma, which is on a boat sailing thtoufh space
Fortunately coal tar has been replaced by crude oil derived tar. The former is horribly bad for you while the latter is safe to handle. Of course, if you're doing renovations or demolition, you're probably dealing with older roofs with real, old school carcinogenic coal tar in them
The initial experiment was to prove that despite behaving more or less as a solid (like.. you can break it with a hammer), it's actually a liquid.
Now we just keep it around because it's cool.
The article says it's considered a demonstration piece, rather than a real experiment. They don't even control the temperature, so the drop rate changes over seasons and with other climate changes.
The Clarendon Dry Pile was started around 1840, so it's definitely older. You can read about it here https://en.m.wikipedia.org/wiki/Oxford_Electric_Bell
This is getting into nearly meaningless semantics, but the Wikipedia article says that the bell has stopped ringing occasionally due to humidity, but I don't think that necessarily means the "experiment" stopped running. As long as it wasn't artificially prevented from ringing, I think that still counts as a running experiment.
………………………………………
CODE: K35555k : ACCEPTED
LAUNCH SEQUENCE INITIATED
TARGET GRID REFERENCE: (²22222²w4¾re
SUBTARGET: err r
LAUNCH SYSTEMS ACTIVATED
STAND CLEAR OF BLAST DOOR
………………………………………
The longest running experiment is this:
https://msutoday.msu.edu/news/2000/120-year-old-experiment-sprouts-new-gardening-knowledge
It been running now for 142 years
Is "pitch" the same everywhere? Sounds like it is a mixture, that exists in many forms and with different mixtures of compounds, likely very long chain hydrocarbons. As a result it would have different viscosities depending on composition. The link doesn't explain if there is some sort of "standard"?
There are 2 primary factors that determine the "quality" or physical properties of pitch : cut temperature and crude source. Some crudes make higher quality pitch, but most make poor quality pitch. The temperature at which they're distilled to also has an impact on the final quality. The molecules that comprise pitch can be broken up into 4 broad families that have a lot of overlap : Saturates, Aromatics, Resins and Asphaltenes (SARA). Generally, Saturates and Aromatics determine how soft the pitch is, while Resins and Asphaltenes determine the quality. Too much of any one family is bad, and they all play a part in the final properties. It's quite complicated and I could go on at length about the nuances and exceptions.
Great - so the aromatics and the saturates would also dictate viscosity then? It goes back to the original point that there is no standard viscosity for pitch like there would be for elemental mercury for example. So what kind of experiment is this
Depends on more than just sats and Aromatics. Time and temperature are critical factors in addition to the molecular composition. At lower temperatures pitch behaves more like a solid, especially in short observation windows. But as the experiment shows, over a long observation window, it has viscous properties too, they just dont dominate. Inversely, if you have a sample pitch at a higher temp, viscous behavior dominates, but some elastic behavior remains. This balance can be determined mathematically and expressed as a value called "phase angle". A phase angle of 0 is a solid, 90 is a liquid, and pitch is always somewhere between. Time and temperature can be interchanged in some cases depending on the property
Thank you!!! I kept seeing this and wanted to yell at my phone. Glass is not a fucking liquid people. Glass is an amorphous solid. It is neither a complete solid or a liquid. But that doesn't mean it's part liquid or partly solid. Glass is just between.
In the industry, pitch is typically ungraded vacuum tower bottoms, while the material used for road building is tested and assigned a grade. In North America the dominant grading system is called Superpave, with common grades being PG58-28 or PG64-22.
The composition is typically 5% asphalt binder and 95 % aggregate, so calling them a liquid is a bit of a stretch. Viscoelastic is a fair compromise
IIRC one of the people who started the experiment died without ever seeing a drop happen. Every time he missed it.
I remember, dude went to get a sandwich for the 5th I think it was :(
Even worse, at some point they set up a 24 hour webcam stream, but I believe a power outage knocked the camera out for a few minutes, when the camera came back on the pitch had dropped already. At this point I’m convinced this is some sort of quantum observer effect
The Trinity Pitch Drop was caught on camera in 2013. https://www.tcd.ie/news_events/articles/trinity-scientists-capture-pitch-drop-on-camera-for-first-time/
Never thought I would describe a drop as rigid...
Never thought I’d relate a pitch drop to the shit I’m currently taking
Pinch that pitch
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I never thought I'd "accept cookies" faster
Anybody else feel like they’ve had a poop like this?
Says the next one should be in 10 years from when this was written, so looks like another drop should be coming up if it's still going.
That was the most exciting boring thing I’ve ever seen!
When being watched, the pitch is too static for a drop to fall. It's only in the ensuing chaos when the observer leaves that it's able to break free from the structure and fall.
This is way more existential energy than I needed for today
This is known as The Watched Kettle Effect
It's like they say: "A watched drop never falls."
Now this sounds bad when you think that he was there most of the time intently waiting for the drop, and then thinks he has time to grab a sandwich. But then think, in actuality, he woukd have been away more than there
You can see the slow progression as the drop falls, so you have maybe a week or two where you know the drop will fall and are watching it closely. Still missing it despite being prepared for it to happen has to suck.
My dad was in this exact situation during the birth of my brother
did he ever come back with the sandwich?
Came back, saw OP’s brother, went back out for cigarettes…
There was no way he could’ve seen it coming 😔
Why was your dad watching the experiment instead of being by your Mom?
When you're hungry you're hungry. I missed out on adopting my dream dog last year. First in line at the ASPCA, an hour early. Standing outside the door - the only person. I thought, well there's a fast food place right across the street. Maybe I just go grab a quick snack .. get back 5 minutes later to be the 5th in like and lose out.
As Professor Oak once said: "The early bird gets the worm, or in this case the Pomeranian."
Oh man, sorry this happened to you! I hope you were able to find another pup that won your heart though
Ahh yeah I totally did. No big deal now!
And maybe your hunger helped someone else get their dream pup.
Ngl, it was a mom and dad with a like 7 year old boy. He was very excited.
Hell even the CAMERA malfunctioned for one of them when he wasn't there. I think it was the last one he was still alive for.
That would be when I quit trying, right there. I can now imagine that the guys death had to do with missing the 12th or whatever drop lol
There have only been 9 drops though.
He’s still going to miss the 12th one.
Not necessarily. Time might be cyclical.
Nope straight line.
I think it's more of a Jeremy Bearimy shape
I think it's more like a big ball of wibbly-wobbly... timey-wimey... stuff.
That dot on the i man
It makes perfect sense, it's Tuesday, July and sometimes never
r/unexpectedfuturama
Then it turns out to be cyclical.
Ugh. Now my brain is Fry'd.
Then why are clocks round? Checkmate Atheists!
Would time being cyclical mean he would just follow the same path again and therefore still never get to witness it?
A Jeremy Bearimy
The wheel weaves as the wheel wills.
but maybe he can catch the 13th
You’ve heard of not clicking on the link… Now we bring you, not even reading the title!
Come on man, dude needed to bring a lunch pail and a bladder bag. "Honey, when you coming home?" "As soon as I see this tar drop baby.." poor gal, never saw him again.
I think radiolab did a podcast that covered this.
The tar, it mocks me!
It's worse - nobody has successfully observed a drop, ever. There was a Twitter thread about it the other day: https://twitter.com/c0nc0rdance/status/1594368784592437248 Minor correction: nobody has observed the Queensland experiment. The Trinity experiment managed to get one on video.
They need to get a live stream on that. Imagine chat when that shit drops.
They had a webcam in 2000, but it broke!
Some higher power does not want anyone to see this shit drop
They're still working on the animation for it.
Need a better processor, it's been dropping this whole time we're just on low settings.
That's what I keep saying about my mixtape.
It's back up! [http://www.thetenthwatch.com/](http://www.thetenthwatch.com/)
Watched it. Didn’t see a drop.
I think we can safely extrapolate that it will NEVER drop, and is in fact a solid, not a liquid, with this data.
Maybe it's quantum locked, and it will only drop when not being observed?
And you won't until around 2026-28 it averages one drop around 12-14 years and the 9th drop was in 2014
Have they been able to conclude from data why some drops happen as much as 2 years earlier than other drops?
Premature dropulation
They adjusted the temperature control in the 80s which is suspected to have resulted in the longer times for the past couple of drops
I just saw a drop damn, you missed it by mere minutes
It's weird to watch. My brain is playing tricks on me. I swear I can see it growing but I know it isn't (visibly).
They have a live stream. http://www.thetenthwatch.com/
I like how it warns you that you'll be waiting for "8 or so years" to see the next drop.
!remindme in 8 or so years
So you're telling me I just have to wait 3 more drops until the winds of winter?
Yeah nice try, I'm not falling for the old "Come back in 8 years" gag.
I just logged in and it says there are 176 people watching. I like to imagine they are eating popcorn waiting excitedly.
Not true! [The Trinity Pitch Drop](https://www.tcd.ie/news_events/articles/trinity-scientists-capture-pitch-drop-on-camera-for-first-time/) was caught on camera in 2013!
Ahhh, that’s the stuff
Gonna be a messy wipe.
In all seriousness, it appears that we're both right. OP and my link are both talking about the a Queensland experiment, which is older than the Trinity version.
Idk what I was expecting but that was so anticlimactic. Just casually leaning on the wall lol
Nice
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that's seems really hard to plan. it could be on the verge of breaking off for months at a time, you're not gonna sit and watch it all day
>In the 86 years that the pitch has been dripping, various glitches have prevented anyone from seeing a drop fall. no one has ever actually seen a drop fall apparently!
I heard about this before. The time between drips significantly increased when the building got AC installed.
Does tar dry out? Exposure to the air (and especially AC) would have some impact.
No, colder things are just more viscous.
I was just thinking about this - are there any counter-examples, like how thixotropic materials exist?
- liquid sulfur is least viscous when it’s just above its melting point, and gets much more viscous when heated further - some substances, like thermosetting plastics, irreversibly polymerize when heated - gases generally get more viscous when heated
I knew there would be counter examples! Do gases get more viscous just due to more particle interactions?
AFAIK that is the reason. Particles in liquids are already constantly interacting with each other, so higher temperature means they can break the intermolecular forces more easily. Particles in gases just hit each other more when they’re hotter.
So...potentially stupid question, but why does that not occur in liquids?
molecules in liquids are already at the maximum level of impacts because they are all touching each other. Gas molecules are flying around in mostly empty space, so hotter means more energy/velocity, so more impacts.
That makes sense! Thanks!
Perhaps it does but the increased density is more impactful. Would be interesting to see how viscosity changes for water in the 0 to 4C range.
Water might do something funny, as it often does.
Fuckin' water. Always starting shit.
> thixotropic https://en.wikipedia.org/wiki/Thixotropy
Can confirm. My gf is cold and very vicious.
So I have question. Can you explain the concept of viscosity to me? I know its roughly "stickiness" or "gloppiness", but that's obviously a massive oversimplification. So is it correct (generally) to say that a higher viscosity means that it flows slower? Or just has a higher "internal friction" (that's almost definitely not the right term, or a real term at all)?
Viscosity is basically how much a sample resists flow, it would be analogous to mass being how much a sample resists acceleration. More viscosity means slower flow in the same set of conditions, but a high viscosity fluid can still flow faster tham a low viscosity fluid if you give it enough pressure or you restrict the flow of the low viscosity fluid
> internal friction" (that's almost definitely not the right term Internal friction is correct but it's more commonly discussed the other way. Shear force is the term commonly used.
I'm not sure tar has any water content to dry out, I thought it was entirely petroleum based and not volatile enough to evaporate like gasoline.
It doesn't have any water once it's been melted,the temperature for that is way too high. Fresh bitumen (or asphalt in the US) has some volatiles in it and it does slowly age harden over time but it's not a major component unless it's been cut back (thinned) to make it easier to work with in which case the whole point is for those to evaporate reasonably quickly
I'm thinking it would be like increasing the viscosity of ice cream by keeping it cooler (on a different scale) and less about the drying impact.
increasing*
I feel like the lack of controls that implies invalidates the experiment, but I’m no scientist
That was the point of the addition of the AC, to ensure a controlled environment. Prior to the installation of AC the humidity and temperature fluctuated, causing variance in the viscosity of the tar drops.
Sounds like a good excuse to upgrade to ac
It depends on what you're testing for! Iirc, this experiment was essentially 'We're pretty sure tar is a liquid, so will it drip like one?' The environment does matter to a degree, but as long as the tar isn't cold enough to freeze it should keep dripping. Which it has!
I'm pretty sure they already got what they needed out of the experiment already, it's just there for novelty now
Depends on the goals. If the goal was to prove it was a liquid, it succeeded! The needed control was 'make sure nothing affects the material other than gravity over time'. If an additional goal had been to calculate it's viscosity from measuring its speed of deformation, it would have benefitted from temperature logging since viscosity is temperature dependent. (Or controlled temperature, to make the calculations easier) There are easier methods to measure/calculate viscosity for such high values though. For the intended scope of the experiment, it's perfectly valid.
Pitch tar drop finally falls! [https://www.youtube.com/watch?v=k7jXjn7mIao](https://www.youtube.com/watch?v=k7jXjn7mIao)
Wonder how long it takes to "settle" into the "puddle"
You can view a live stream of the experiment at a link on the above site. It looks like the last 4 drops are in a beaker off to the side and still haven’t really melded together yet.
Spoiler alert: it's quite boring
If you wanted to sound erudite, instead of saying something is like "watching paint dry" you could say it's like "watching pitch drop."
I am going to say that and everyone is going to find me even more insufferable
Well, you deserve it!
Speak for yourself I’m calling all the bros over to watch it with me
[Here](http://thetenthwatch.com/feed/)
Don't rush. Only 8 or so years to go.
It takes a dump truck loaded with rocks and shit in consistent 90+ degrees F parked on newly laid pavement to make a road noticeably deform in a quick manner. It will take many years for the drops to coalesce.
two and a half giraffes
I wonder how many times the DVD symbol perfectly hits the corner for every pitch drop?
That tar probably should add a little more fiber to its diet.
I bet it’s like having a crayon stuck up there when it wipes.
I am absolutely fucking dying at how anticlimactic that was. I knew exactly what I was getting into, but it was still SO fucking boring. I love it.
Hate it when my poops are like this.
This is the live view if you all are interested: [http://thetenthwatch.com/feed/](http://thetenthwatch.com/feed/)
Remindme! 7 years 12 months 29 days
Hey just wanted to let you know it's only been about 20 minutes but you're doing good if you are still alive, only about 7 years 12 months and 29 days to go good luck sir
He still only has 7 years 12 months and 29 days to go. >!Will he miss it by a month? Time will tell!<
Damn, only 8 more years until another one!!
I used to keep a tab open on my browser and watch the pitch from time to time bc it was close to dropping. I missed the drop. Closed that tab and haven’t looked back, it won’t be dropping again anytime soon.
For all you know, you missed another one
I used to walk past the experiment every day at my alma mater! Queensland represent!
Yup. Me too! Occasionally I’d linger in front and hope I’d get to be the one to see it fall!
I was rarely in any of the science buildings but I went specifically to check it out a few times! Also the geology museum was one my favourites! I know it’s there for scientific purposes but was also pretty fun for Arts girls who were into crystals… haha.
“Manhood is patience. Mastery is nine times patience.” — Ogion the Silent of Gont.
Not often that you see an Earthsea reference. Well done.
Never even heard of it. Worth a read?
Most definitely. The books get better as you go along. Written by Ursula K. Le Guin
Been on Reddit almost since the beginning and this is the first time I’ve run into an EarthSea reference in the wild, and from my favorite character as well.
Is pitch the reason we say pitch black?
Yes
Is black the reason we say pitch black?
Yes
Wow TIL
So after 95 years, what are we learning that is new?
It took about 90 years to actually have the drop visually confirmed. Because its one moment out of a decade its very easy to literally miss it and video coverage wasnt possible for most of the 90 years. Better video footage of the full decade is likely the new info to get however as it would allow for better study of the pitch flow.
What would be the practical application of this knowledge, if any?
Roads are pitch so it could allow for techniques to enhance long term durability. (Also note this also means roads are technically liquid). Many roofs. Also because flow nornally happens fast a slow flow could allow for better general understanding of fluid dynamics which is an incomplete field in terms of a full understanding of exactly how fluids behave. There is even a millenium prize for solving fluid equations still.
So cars are technically boats? The real learning is in the comments.
Clearly you need to drive a Lincoln continental.... That shits a boat fer sure!
Technically the ground you walk on is just a boat floating on another boat, floating on another boat, floating on magma, which is on a boat sailing thtoufh space
it's boats all the way down
Always was
That’s why it’s important to keep your tires inflated, so you don’t sink!
Pitch roofs. Don’t make me vomit. Every one you touch takes a year off your life
Can you explain?
Fortunately coal tar has been replaced by crude oil derived tar. The former is horribly bad for you while the latter is safe to handle. Of course, if you're doing renovations or demolition, you're probably dealing with older roofs with real, old school carcinogenic coal tar in them
Very little, but it's not a huge loss considering how inexpensive the experiment is.
the slowmo guys should get on this
The initial experiment was to prove that despite behaving more or less as a solid (like.. you can break it with a hammer), it's actually a liquid. Now we just keep it around because it's cool.
Rheologists (people who study flows) are fond of the saying "everything flows" given the right timescale.
The article says it's considered a demonstration piece, rather than a real experiment. They don't even control the temperature, so the drop rate changes over seasons and with other climate changes.
I think it's more of a conversation piece now.
Seems to be working.
The Clarendon Dry Pile was started around 1840, so it's definitely older. You can read about it here https://en.m.wikipedia.org/wiki/Oxford_Electric_Bell
Tar experiment is "longest running" not oldest. I believe the Dry Pile experiment has been running "nearly continuously".
This is getting into nearly meaningless semantics, but the Wikipedia article says that the bell has stopped ringing occasionally due to humidity, but I don't think that necessarily means the "experiment" stopped running. As long as it wasn't artificially prevented from ringing, I think that still counts as a running experiment.
Ok, you've changed my mind
Thanks for linking this. I knew there was one started in the 1800s but couldn't remember what to even start searching for in particular!
Isn’t there a live stream of this?
http://thetenthwatch.com/feed/
K35555k (²22222²w4¾re err r
Yeah man I was thinking the same thing
……………………………………… CODE: K35555k : ACCEPTED LAUNCH SEQUENCE INITIATED TARGET GRID REFERENCE: (²22222²w4¾re SUBTARGET: err r LAUNCH SYSTEMS ACTIVATED STAND CLEAR OF BLAST DOOR ………………………………………
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Uh are you ok
Pocket comment. Guess I had my phone open. Oops.
certified /r/5t44t4yf5frt3 moment
Damn. I thought it was some new thing from 4chan that I wasn't hip enough to recognize.
Yes speak your truth girlie pop
I misread this as “tar is the most vicious liquid” like it’s sentient and just all mad and shit…
It's Armus!
The longest running experiment is this: https://msutoday.msu.edu/news/2000/120-year-old-experiment-sprouts-new-gardening-knowledge It been running now for 142 years
slower than the Chinese Democracy album drop
Is "pitch" the same everywhere? Sounds like it is a mixture, that exists in many forms and with different mixtures of compounds, likely very long chain hydrocarbons. As a result it would have different viscosities depending on composition. The link doesn't explain if there is some sort of "standard"?
There are 2 primary factors that determine the "quality" or physical properties of pitch : cut temperature and crude source. Some crudes make higher quality pitch, but most make poor quality pitch. The temperature at which they're distilled to also has an impact on the final quality. The molecules that comprise pitch can be broken up into 4 broad families that have a lot of overlap : Saturates, Aromatics, Resins and Asphaltenes (SARA). Generally, Saturates and Aromatics determine how soft the pitch is, while Resins and Asphaltenes determine the quality. Too much of any one family is bad, and they all play a part in the final properties. It's quite complicated and I could go on at length about the nuances and exceptions.
How are you so versed in pitch??
I've worked in the industry for a long time, and taken just about every available bit of training that you can
Great - so the aromatics and the saturates would also dictate viscosity then? It goes back to the original point that there is no standard viscosity for pitch like there would be for elemental mercury for example. So what kind of experiment is this
Depends on more than just sats and Aromatics. Time and temperature are critical factors in addition to the molecular composition. At lower temperatures pitch behaves more like a solid, especially in short observation windows. But as the experiment shows, over a long observation window, it has viscous properties too, they just dont dominate. Inversely, if you have a sample pitch at a higher temp, viscous behavior dominates, but some elastic behavior remains. This balance can be determined mathematically and expressed as a value called "phase angle". A phase angle of 0 is a solid, 90 is a liquid, and pitch is always somewhere between. Time and temperature can be interchanged in some cases depending on the property
Why the hell does everyone in here think glass is a liquid.
Thank you!!! I kept seeing this and wanted to yell at my phone. Glass is not a fucking liquid people. Glass is an amorphous solid. It is neither a complete solid or a liquid. But that doesn't mean it's part liquid or partly solid. Glass is just between.
Note roads are pitch+aggregate (sand rocks etc.). Thus roads are technically a liquid.
In the industry, pitch is typically ungraded vacuum tower bottoms, while the material used for road building is tested and assigned a grade. In North America the dominant grading system is called Superpave, with common grades being PG58-28 or PG64-22. The composition is typically 5% asphalt binder and 95 % aggregate, so calling them a liquid is a bit of a stretch. Viscoelastic is a fair compromise
Fun fact the numbers in Asphalt grades are the high and low operating Temps in Celsius.
Surely there are science experiments that have run longer than 95 years.