The h Bar

4:00 PM

OK, time to get started! Welcome to our chat session everybody.

Please keep unrelated discussion until the end of the session, or take it to another room.

Here's the agenda for the hour:

1. Intro, welcome newcomers, take policy questions (<10m)
2. Recent physics developments (5m)
3. Thoughts on the VLQ flag experiment (20m)
4. Update on the replacement for the homework policy (25m)
5. Open discussion

So, first up: who's new to the site, new to chat, or new to chat sessions?

privetDruzia

I m new to events like those

David Z

@privetDruzia First chat session I presume?

privetDruzia

yes

David Z

Welcome, then. This is something we do every couple weeks to (attempt to) bring the community together.

privetDruzia

ok

DanielSank

4:03 PM

Soooo, policy questions?

David Z

Or any sort of general question about the site, I guess it doesn't have to be policy

DanielSank

Not hearing any. Do we move on or wait the allotted time?

David Z

Well, we can still take those before we get into the main topics. For now, if people aren't saying anything, we can move on to recent physics developments.

@DanielSank I figure it holds in general that if we give it a couple minutes and nobody's contributing, it's time to move on.

vzn

Supersymmetry Bet Settled With Cognac / wolchover, quanta mag

John Rennie

Hawking radiation

David Z

4:07 PM

@vzn ah, yeah, I've been seeing a lot of that on Twitter

@JohnRennie Entanglement? I hadn't heard about entanglement being involved or simulated or whatever in these experiments

DanielSank

@JohnRennie talk about misleading titles

The entanglement is related to these fact that you're looking for pairs of particles.

vzn

@JohnRennie very much like the idea of sound waves used as standin/ analog for light, have other ideas about that have long wanted to develop further wrt QM etc

DanielSank

Gotta go, court's in session

John Rennie

@DanielSank remember your black cap

David Z

Hi @sunqingyao

@DanielSank Huh, I'll have to read about that more closely

ACuriousMind

4:11 PM

@JohnRennie relevant arXiv link

John Duffield

All : see Woit's blog about the SUSY bet: "The losers of the bet who spoke, (Arkani-Hamed, David Gross and David Shih) demonstrated the lesson about science that supersymmetry and superstring theory have taught us: particle theorists backing these ideas won’t give up on them, no matter what."

ACuriousMind

It's...not teXed. The horror!

David Z

@ACuriousMind Yeah, I saw "PDF only" and felt sad :-(

Anyway, not much activity on this topic. Shall we move on to the VLQ experiment?

ACuriousMind

I already have to cringe when I read the first page.

vzn

@JohnDuffield physics has a general crosscutting challenge with testing extremely subtle effects/ theory etc at this point, it manifests in many areas

ACuriousMind

4:14 PM

Hawking did not predict that nonsense with the pairs. He predicted Hawking radiation and explicitly stressed in his paper that the picture of the virtual particle pair that gets separated by the horizon is a heuristic.

vzn

@ACuriousMind some heuristics can be "eventually" formalized/ even verified etc...

Secret

I am not sure how relevant acoustic analogues to gravitational problems, since the riemann curvature tensor is a more complicated object than whatever that describe acoustic phenomenon

David Z

Well this is interesting but we should actually move on now. We're 15 minutes in.

Secret

Ok, present the results and stat of VLQ

David Z

It just ended, we don't have statistics yet.

Secret

4:16 PM

ok, raw data then

David Z

Nor that

John Duffield

I share Chris White's concerns re VLQ deletions.

David Z

Right now I'm hoping to collect qualitative impressions.

Any thoughts on how the experiment went? Did anything seem different?

John Rennie

It was nice being to vote LQ without fear of a ban, but I'm not sure I noticed any difference in the size or content of the VLQ queue.

2

David Z

BTW we will get quantitative data later, from SE, if at all possible.

ACuriousMind

4:19 PM

@JohnRennie I think that would've been difficult since the LQ queue is fast-moving to begin with

David Z

What about in terms of the quality of posts on the site? After all, the whole point of this is to be able to delete a certain class of posts, not just downvote them.

John Rennie

It would be interesting to see how many VLQ flags were raised during the fortnight compared to the baseline.

David Z

@JohnRennie Yeah, that's the sort of thing I'm hoping SE will tell us.

ACuriousMind

@DavidZ Honestly, without the featured post about the "experiment", I would never have noticed that aynthing was going on

I'm also not sure how many users were actually aware it was supposed to be going on

John Rennie

It's hard to judge on the end results because I normally only look through new posts, so I see them before any votes to delete.

David Z

4:20 PM

Yeah, there wasn't much fanfare to it.

ACuriousMind

Case in point: meta.physics.stackexchange.com/q/9067/50583

John Rennie

To judge we'd have to look at the stats for how many questions got deleted during the fortnight compared to baseline.

ACuriousMind

User asking during the experiment to "confirm" that they should vote looks OK on wrong posts

This gives me the impression that users less concerned with meta really had no idea

Which is a general problem with anything on meta: The participation is really low compared to the main site, in my impression

David Z

Yeah. Well, it was announced in chat and the meta post was featured, but there isn't really anything more than that we can do to promote things.

@ACuriousMind I think that's to be expected.

John Duffield

Apologies, I've got to go.

ACuriousMind

4:22 PM

@DavidZ I know. I'm just saying it is not clear whether e.g. any absence of effect in the statistics is due to the idea of the experiment not changing anything or due to users simply doing business as usual without regard for the experiment.

John Rennie

How are we going to judge whether it's worth continuing? What criteria?

ACuriousMind

@JohnRennie I'm still not sure exactly what hypothesis we were testing here

David Z

@JohnRennie Well, right now it's not continuing. Flagging is back to normal.

This is one of the things we could discuss now. Any ideas of what criteria we should be looking for?

John Rennie

:: John nervously checks his flag stats ::

vzn

@ACuriousMind bummed about that too, find its scattered, some meta posts have very high votes in short time eg DSs chat session announcement... agree that any widescale efforts to chg site direction are sometimes like (attempting to) "boil the ocean"

John Rennie

4:25 PM

Can we get a list of deleted posts in the last fortnight then review them to see if they really deserved it?

Or maybe look at the downvote activity in the last fortnight compared to baseline?

sun qingyao

@DavidZ Hi

John Rennie

The point was to draw attention to posts that should be downvoted and/or deleted.

ACuriousMind

@DavidZ No idea. We've already discussed a week ago or so that I thought we should've sorted out the problem we're trying to solve more clearly beforehand

David Z

Well, the point was also to be able to delete posts which the mods would ordinarily consider not worthy of deletion.

vzn

@DavidZ funky/ kinda strange expr "(not) worthy of deletion"...

David Z

4:29 PM

I had some ideas about what statistics to collect but right now my mind is on the homework policy replacement so I don't remember them off the top of my head

I guess I should have made notes ;-)

Ultimately, the problem was that there were posts which (some? many? most?) people thought did not deserve a place on this site, but which were not considered deletable by the mods. If the experiment "worked", the site should have seemed cleaner because those posts were being deleted.

vzn

@DavidZ thx for the clear tl;dr summary that eluded EP for many paragraphs! ... finally

0celo7

I solved one of my QM homework problems in high school and have a TeXed solution.

Yay.

David Z

This is why I want to collect impressions. Those people who perceived a problem before should be noticing a lack of that problem now. Of course, it's possible that two weeks is not long enough to get a "statistically significant" impression, which is one thing that quantitative stats might tell us.

Anyway. I think it's about time to move on to homework policy stuff.

Any last thoughts on VLQ flags, other than what has already been brought up?

vzn

@DavidZ @Emilio seemed to have huge stake, would like to hear his further impressions at some pt (maybe he can chime in later)

David Z

Yeah, it would have been nice if he were here. Someone should bug him about this ;-)

DanielSank

4:38 PM

I got ejected from the jury.

0celo7

@DanielSank Did they say why?

DanielSank

Because I'm a scientist.

David Z

lol

ACuriousMind

...what?

David Z

that's how I hear it goes

DanielSank

4:38 PM

They didn't say that outright but that's why.

vzn

@DanielSank have heard that about coders too. "too logical" or something... lawyers want emotionally oriented ppl apparently etc

0celo7

@JohnRennie I managed to cut a piece of copper into a (somewhat) perfect circle so it fits perfectly into the XRD, and I still have 10 fingers!

David Z

Anyway. As far as the homework policy thing goes...

0celo7

Proof of concept for the plutonium substitutes

David Z

I have a decent amount of data on the responses posted on the meta question. (let's see if I can find a link)

0celo7

4:39 PM

Diamond band saw is both awesome and scary

David Z

19

Q: Replacing the homework policy 1: what existing questions should be on/off topic?

TL;DR: post examples of current questions which are edge cases for the new policy, look through the list, and vote answers UP if you think they should be ON TOPIC vote answers DOWN if you think they should be OFF TOPIC Also, if you feel motivated, fill out this questionnaire ...

@0celo7 we're talking about something else now

0celo7

@ACuriousMind ::ACM's confusion with the American court system intensifies::

@DavidZ Just as well, QM lecture now

ACuriousMind

@DavidZ So, where's the data?

David Z

I'll post it shortly

I was in the middle of figuring out whether I needed to anonymize it when the session started

Anyway, I made a plot of the score of each question's answer

The error bars show Wilson score confidence intervals at $\alpha=0.05$, so basically $2\sigma$

What this shows is that we could use more votes, especially on the newer answers

DanielSank

YES

More votes.

But what are we trying to take away from this anyway?

Someone's going to have to interpret the results.

Meanwhile, we have a meta post enumerating objective problems and inconsistencies with the homework policy.

ACuriousMind

4:47 PM

I thought David had also that questionnaire about what people thought these answers are (low effort, homework, about a computation, etc...) Correlating these evaluations with the votes should tell us what properties people are actually looking at when deciding whether something is on topic or not

DanielSank

Can we not fix those problems and also work on the refinement that would come from these data?

David Z

@ACuriousMind Yes, that's exactly the point.

DanielSank

Oh, where's that?

David Z

At some point in the past I posted this plot showing rough correlations between score and various factors from the questionnaire

DanielSank

And can we make this whole issue a community ad linking to meta etc so progress happens?

David Z

4:49 PM

@DanielSank yeah, once I get the data in shape I'll make a meta post.

Anyway, the image suggested that the most important factor was interest: people vote to close posts based primarily on whether they consider the post to be interesting or not.

ACuriousMind

@DanielSank The homework posts are usually featured in the "hot meta post" side bar for a while after they're posted. Who's going to click on a community ad that wouldn't click on that?

@DavidZ Which is the worst possible outcome to base a policy on :P

David Z

I'm working on an updated analysis that takes into account new responses to the questionnaire and additional votes on the answers.

I'll put that in a meta post when I have it.

@ACuriousMind yeah, exactly.

That's sort of what held this discussion up the last time.

DanielSank

@ACuriousMind I dunno, but we've been on about this issue for months and it's a huge pain point when trying to help new users. The ads are a lot bigger than the hot links.

David Z

I was hoping to find a strong correlation between score and, say, tediousness, or something less subjective than interest.

DanielSank

Right but people are lazy

David Z

4:52 PM

Yep.

DanielSank

The homework policy is a dump where people throw questions that they don't rant to take time to evaluate properly.

vzn

@DanielSank the ads are cool but have you ever seen the hit statistics? low... dribble )( of hits per day even on "higher profile" ads

DanielSank

I'd almost say we could just removed it entirely and use the other more useful close reasons.

David Z

The original idea was to redo the policy in a way that reflects more accurately how people wanted to vote. But if people want to vote based on what they find interesting, that's not such a good idea.

@DanielSank Well, yeah. That's the idea. Remove it entirely and use a new close reason.

DanielSank

Woah, I think the policy should guide how people vote, not vice versa.

David Z

4:54 PM

The question is, what should that new close reason be?

(could be two)

DanielSank

I wonder if such reasons already exist.

Absolutely not. I didn't say that at all.

David Z

wait, maybe I misunderstood

ACuriousMind

@DanielSank Well, the original problem was that people voted to close "homework" but we have endless debates about what "homework" is. The idea was that we first figure out what people actually call "homework" and then replace "homework" by whatever they actually mean.

David Z

yep, that

(technically it was "homework-like", not that that really matters now)

DanielSank

@ACuriousMind I understand that but there isn't one reason that people vote to close as homework.

vzn

4:56 PM

@ACuriousMind fyi this is a problem/ pain point/ crosscutting on some other sites even splitting the mods eg Computer Science... it also relates to a semifamous SE meta post by shog9 "should we award As for effort" etc

ACuriousMind

@DanielSank Sure, if there are multiple reasons, then we could've figured that out, too

However, the strongest reason to VTC being "I don't find this question interesting" is a horrible result

Emilio Pisanty

People called? (@vzn @DavidZ)

Re the VLQ flags, I've got a backlog of the harmful posts I really wanted to address (which were intrinsically not easy to find)

I also saw an uptick in LQP queue activity

which needs to be looked at

I'll try to find time but I'm crazy busy at the moment

DanielSank

@ACuriousMind perhaps a good way to avoid that is to get rid of such a confusing and self-contradictory close reason that we presently have.

Just remove it. Is that a bad idea?

vzn

@EmilioPisanty suggest you post that list somewhere

ACuriousMind

@DanielSank Yes.

NeuroFuzzy

4:58 PM

@ACuriousMind Your newest avatar in the tiny chat form looks like codinghorror/Jeff Atwood's avatar blog.codinghorror.com/assets/images/codinghorror-app-icon.png

Emilio Pisanty

@vzn Yes. It's a matter of finding time.

NeuroFuzzy

I was wondering "why the heck is he in chat?!"

David Z

Yep. OK, let me post the stripped data that I have so far from the questionnaire and then y'all can discuss whatever.

ACuriousMind

@DanielSank What are you going to close all the blatant "Do my homework for me" posts for if you just remove the reason?

NeuroFuzzy

KOTOR?

ACuriousMind

5:00 PM

If people are just going to write "I'm voting to close this question as off-topic because it is homework-like", then you've changed effectively nothing.

@NeuroFuzzy Aye, Kreia/Darth Traya.

@NeuroFuzzy lol

Emilio Pisanty

@NeuroFuzzy lmgtfy.com/?q=kotor

DanielSank

@ACuriousMind good point.

Secret

There are some "working on problems" type questions that showed decent effort of reasoning and workings, and those that ask for alternate ways to solve it.

We also need to figure how to handle the is this correct, what is wrong type of questions

NeuroFuzzy

@EmilioPisanty :p I was asking if it was from KOTOR

Emilio Pisanty

@NeuroFuzzy hah

sorry

Secret

5:01 PM

The very low quality of "working on problems" type questions are IMO, those that don't even try to start the reasoning or calculation in the first place

but then, there are also those layman questions, which can look like the low quality questions above

David Z

,QID,Effort,Level,Conceptual,Interest,Tedious,Context,Check My Work,Correct?,Detailed Calc,Question URL,Research
0,247719,3.0,2.0,1.0,2.0,2,4.0,0.0,1,1.0,physics.stackexchange.com/revisions/247719/1,3.0
1,7671,5.0,2.0,1.0,5.0,4,5.0,0.0,1,0.0,meta.physics.stackexchange.com/a/7671/124,
2,252007,5.0,1.0,1.0,1.0,3,5.0,0.0,0,1.0,physics.stackexchange.com/revisions/252007/1,5.0
3,253477,1.0,3.0,3.0,1.0,5,5.0,0.0,0,0.0,physics.stackexchange.com/revisions/253477/2 (deleted),1.0

cool, that worked. Those are the questionnaire responses as of the start of the chat session.

DanielSank

I'll just throw this up there again

25

Q: Should we rename the homework policy?

The homework policy is a constant source of confusion for new (and sometimes established) users. We see this confusion, for example, when users respond to closures based on the homework policy by defending their post with "This is not a homework problem", or similar. Some users have even been con...

discussion tags questions homework

Emilio Pisanty

That said, I have had some further thoughts on the queue, which I'll also try to post. In particular, I'm less convinced that we have enough scrutiny for the proposal to work well. (That is: a strong enough population of 10k users going through the 10k tools to follow up on recent deletions to check nothing bad slipped through.) I need to think that some more before I post, but it's something to consider.

David Z

QID,URL,Answer posted,Upvotes,Downvotes,Score,Votes,Approval,Wilson Upper,Wilson Lower
247719,physics.stackexchange.com/questions/247719/… 07:08:42Z,26,8,18,34,0.7647058823529411,25.542849837805086,6.802626212675255
247547,physics.stackexchange.com/questions/247547/… 07:30:57Z,21,9,12,30,0.7,20.00115103905372,1.2745275247710186
247730,physics.stackexchange.com/questions/247730/… 09:55:26Z,4,11,-7,15,0.266666666666…

DanielSank

There are explicit suggested rewordings there and my take on what the problem is.

vzn

5:03 PM

open session yet for mtg? am really bummed at zero votes on this call for speaker ideas. no luv from the audience or cohorts despite massive sustained effort over last few mos. :( ... meta.physics.stackexchange.com/questions/9068/… am thinking guest speaker session maybe should go on hiatus :(

David Z

That's score data from the answers

OK, chat session is over!

See everyone in two weeks!

Emilio Pisanty

@DavidZ Sorry, what exactly is that data?

David Z

@EmilioPisanty That's collected from the answers to the question I linked earlier - the one where we were voting on what should be on or off topic.

Emilio Pisanty

@DavidZ ok, got it

David Z

That's all public data, you could go get it yourself from the question page. I also calculated some statistics.

I'll put all this in a meta post too, soon.

Emilio Pisanty

5:06 PM

To be honest, I really feel that we ran out of steam on that one

I've developed a pretty strong 'oh, god, again?' visceral reaction to discussions of homework

David Z

@EmilioPisanty Well, on one hand, more data is always better, but the question served its purpose. It's the analysis that's proving tricky.

John Rennie

The problem is that the homework policy is intended to keep this site an attractive place for the active answerers.

David Z

@DanielSank That's exactly what we're trying to do, but better.

@EmilioPisanty feel free to ignore it ;-)

John Rennie

The world won't end if we open the gtaes to homework, but all the active answerers will get fed up and leave, making the site a worse place.

David Z

I'd leave

DanielSank

5:08 PM

@DavidZ I think the analysis is tricky because we don't know why were voting as we do. Perhaps a less confusing close reason will help us vote more clearly?

John Rennie

So ultimately the definition of homework is what hacks us off

DanielSank

Noooooo

John Rennie

And we're trying to put an objective definition on what hacks us off

vzn

@Secret that ofc will be the conventional wisdom objection but dont forget Tenev/ Horstemeyer... very strong connection/ correlation between riemann curvature and fluid density analogies although almost nobody realizes it yet... "the future is already here, its just not evenly distributed" —wm gibson =D

David Z

@DanielSank I think it's the other way around, voting will help us determine a less confusing close reason.

John Rennie

5:09 PM

But that's entirely subjective.

DanielSank

No! Dammit no!

John Rennie

Amazingly, the most important factor appears to be whether a question is interesting - I rest my case.

vzn

@JohnRennie not sure why you say thats a "problem"

ACuriousMind

@DanielSank I don't think any of the close voters is confused by the close reason. Your point about the wording is valid, but it's mainly confusing to the people who get their post closed and can't really determine why. I'd guarantee that each of the close voters has a strong personal conception of "homework" and VTC any question that fits it. The problem is that those conceptions don't seem to match what's written in the policy.

DanielSank

We just want questions that lead us to think that the op is asking in good faith.

John Rennie

5:10 PM

@vzn I'm quite happy with interesting as the primary criterion. It's others who think it's too subjective.

David Z

@DanielSank Perhaps so

@JohnRennie :-P

John Rennie

Where by interesting I mean doesn't hack me off

DanielSank

@ACuriousMind you don't think growing up in a country with laws affects your own morals?

ACuriousMind

@DanielSank I think the data we got, where "interesting" is the strongest criterion, would indicate something else: People don't care wtf the asker's motives are as long as they derive joy from tackling the question.

vzn

@JohnRennie closing questions will always have a substantial subjective component and think those that are seeking something otherwise are chasing mirages, although admittedly SE thinking (in search of objectivity everywhere) seems to run counter to that realization...

John Rennie

5:12 PM

> chasing mirages

Quite so.

Though being a Brit I'd say hunting the snark

Secret

@ACuriousMind and that is not very healthy for handling problems

DanielSank

@ACuriousMind yes, and we're giving them too broad a law under which to prosecute.

vzn

@JohnRennie yeah the internet is so snarky lol :P

DanielSank

If it's illegal to be annoying then everyone goes to jail for that reason.

If the law changes people's behavior might too.

John Rennie

@DanielSank Why does whether the OP is asking in good faith matter?

It might make me post an apologetic message before VTCing, but I'd still VTC.

ACuriousMind

5:14 PM

@DanielSank To run with your analogy, we've got a militia who doesn't seem to care what's written in the law, they just arrest the people behaving "inappropriately". But I'd prefer we stay with the topic and don't go off on questionable analogies.

@DanielSank I'm not sure about too broad - the "interesting" criterion means that people actually want questions to stay open that would currently be banned for not asking a conceptual question.

DanielSank

@JohnRennie I just mean we want questions where op is making a real effort to learn. But maybe that's not the right criterion.

Not objective enough.

0celo7

@DavidZ I didn't know a chat event was on, apologies.

Just got the notification.

ACuriousMind

@DanielSank Well, the user wanting to learn and showing effort partly determines whether I vote up or down, but I think that on- or off-topicness is about something different.

John Rennie

@DanielSank actually I agree, and I'll sometimes answer an obvious homework question if I think my answer will be entertaining and informative. Maybe to others if not the OP.

David Z

@0celo7 No worries

DanielSank

5:18 PM

It's a good analogy

ACuriousMind

Remember that being off-topic and being a bad question are two different things. You close one, and you downvote the other.

DanielSank

@ACuriousMind ok good. Makes sense.

John Rennie

Quick poll: who is actually dissatisified with the current homework policy? Seriously dissatisified that is?

vzn

> questionable analogies

John Rennie

I'll go first, I think the current policy works reasonably well most of the time.

If it stayed as it is I wouldn't be crying myself to sleep every night

David Z

5:21 PM

@JohnRennie Not seriously, but then again I kind of wrote it in the first place so I have a pretty clear idea of what it was intended to mean. Rather a significant bias.

DanielSank

@JohnRennie I am dissatisfied with the fact that it is inconsistent with itself and therefore offers those whose questions are closed misinformation about how to fix those questions.

John Rennie

I (almost) invariably append the comment:

Hi and welcome to the Physics SE! Please note that this is not a homework help site. Please see this Meta post on asking homework questions and this Meta post for "check my work" problems.

DanielSank

I think one of the main benefits of this site is that it teaches present and future scientists how to ask questions well.

ACuriousMind

@JohnRennie I'm dissatisfied with the (rare) instances where people leave open a problem just because they find it interesting (happens like once in a month in my perception), but generally the close voting as homework works well. However, I agree with @DanielSank's longstanding points that the practice of closing questions as homework does not match the content of the policy.

John Rennie

And those links are intended to provide guidance.

> However, I agree with @DanielSank's longstanding points that the practice of closing questions as homework does not match the content of the policy.

ACuriousMind

5:23 PM

Which was the reason we wanted to renew the homework policy in the first place. What people called homework wasn't what was written there.

John Rennie

Colour me a pragmatist, but does it matter?

ACuriousMind

@JohnRennie Yes.

DanielSank

@JohnRennie yes

ACuriousMind

If you link users to a post that purportedly explains why their question was closed, it damn well better explain why it was closed!

2

Secret

We definitely want to avoid students asking about exam and assignment questions? no?

John Rennie

5:24 PM

@Secret It isn't as simple as that.

ACuriousMind

@Secret This is so much not about cheating.

If someone manages to ask a nicely written conceptual question, I don't care whether they just need the answer for an exam - the question itself is good.

DanielSank

@Secret no. I don't care at all whether or not a question came from homework and we can't police cheating on exams.

See my meta post.

@ACuriousMind you have a habit of saying things clearly. Thanks.

David Z

@Secret One of the motivations behind the homework policy was to avoid making this site known as a place where students could get help cheating on their homework/exams. Rather, we wanted to create the opposite impression, in the strongest possible terms.

DanielSank

I'm on mobile. Sorry.

ACuriousMind

@DanielSank Ah, no problem

I was just wondering whether that was a botched post or really just a "You!", in which case I'd have to divine its meaning :P

Secret

5:30 PM

what exactly is a conceptual question? I have seen questions where the OP showed the reasoning and working on a problem, yet they don't know what physical idea they are missing in order to continue on the solving (which is not really the same as "check my work" and "why is it wrong" type questions, because they have not get any answers nor check what the book answer is (and for physical modelling scenarios that is not from any textbook, there is no answer to check at all)).

Is this a conceputal question, or is it not because they are seeking for whatever concept that prevent them from comp…

DanielSank

😀

Holy guacamole. Does that render for everyone else?

ACuriousMind

@DanielSank No, I see a unicode placeholder

DanielSank

Dang

John Rennie

@DanielSank Me too

DanielSank

@Secret it's conceptual, and usually all those posts need is a bit of guidance and editing rather than close votes.

ACuriousMind

5:33 PM

@Secret The problem with such questions is that you have to know the answer to decide whether it's a "conceptual" problem or mere mathematical ineptitude that prevents the asker from proceeding. However, if there's a conceptual problem, you should be able to phrase the question such that it's not just "how do I continue?".

DanielSank

\begin{soapbox}

ACuriousMind

I have to go shopping now, I might return

David Z

Buy soap for @DanielSank

DanielSank

I really think it's in the site's own interest to help users learn to ask questions well. This is how we can grow our community and avoid turning would-be contributors away.

I think close reasons should be viewed as educational documents more than license to impose our preferences, because in the end our preference is really good questions.

2

John Rennie

I too have to be off.
It's a good job we are better at physics than reaching conclusions about the homework policy.

2

DanielSank

5:36 PM

I learned a lot about how to ask by observing this site's rules. The rules helped me grow. Please consider this.

\end{soapbox}

Now I have to see a man about a suit.

Secret

https://physics.stackexchange.com/revisions/248365/3

IMO, example of a "why is it wrong" type question where the answer is botherline between mathematical inepitude (because QM is mostly algebra) and conceptual missing piece (that he need to consider a 3D condition)

Therefore, confusing for me to rate in the questionnaire

The difference between physics and maths is that sometimes a physical condition need to be imposed onto the formula to get the correct result.

But otherwise, I agree on what ACM mentioned about the phrasing of a question to highlight the conceptual bit

David Z

@ACuriousMind Yeah. I don't like "what do I do next?" kind of questions because they strike me as just mini-versions of "how do I solve this?", and I think they should be off topic for the same reasons.

0celo7

6:13 PM

@DanielSank on my phone, yes

@DanielSank And on my laptop too.

0celo7

6:36 PM

$$\iiiint$$

who uses that

NeuroFuzzy

@0celo7 Lol

$$\int_{\mathbb{R}^4}$$ must just be too verbose.

Secret

6:52 PM

$$\int \cdots \int$$

Very rare but do exists

0celo7

Oh for the love of god

QM problem set just got 10x worse

Explicitly compute the commutation and anticommutation relations of the spin 1/2 operators

pretty sure there's a typo in the homework, great.

NeuroFuzzy

7:16 PM

Why not $\uparrow$ and $\downarrow$?

0celo7

@NeuroFuzzy Because no one does that?

privetDruzia

What is the difference between $Q = mc\Delta t$ and $Q = mL$ where L=latent heat, c = heat capacity

what is the difference between L and Q?

yes @0celo7 ?

found it, is OK :)

however there is some very close correlation which is unknown to me

I now found both "definitions" online

but the difference is very subtle

"Specific heat is the amount of heat required to raise the temperature of a substance a certain amount. Latent heat is the amount of heat released during a change of state, i.e. the boiling of water or the melting of ice."

But the latent heat is a form of specific heat....

I think...

DanielSank

7:54 PM

@JohnRennie Huh?

@JohnRennie Given your repeated statements about how you care about the site as an educational resource, I'm surprised by your flip attitude about the homework policy!

NeuroFuzzy

@0celo7 People use it! $|\uparrow\rangle$ and $|\uparrow_x\rangle$ etc look way better. The spacing for + and - just suck. Many of my classmates ran to the professor wondering what the expectation value of the $-$ operator is (because $|+\rangle\langle +|-|+\rangle\langle -|$ looks like it has a factor of $\langle +|-|+\rangle$ in it) when our professor switched to that notation

@privetDruzia So what is the problem here? During a change of state the temperature is constant

ie, to go from ice to liquid water at 32F, you expend energy to change the state of the material, but everything stays at 32F.

So the definition cannot depend on delta t, because delta t is zero here.

0celo7

@NeuroFuzzy then your classmates do not understand what is going on

NeuroFuzzy

@0celo7 Says the guy who just commented on how hard to read the commutator relation is :p

0celo7

@NeuroFuzzy Huh?

I just don't want to write all that shit out is all

NeuroFuzzy

8:09 PM

I mean, close enough.

It's much harder to be snarky to you since you proved me wrong about the definition of tangent space in diff geo.

0celo7

@NeuroFuzzy You're free to challenge me on geometry any day :)

that picture above has like 4 typos in it

3 from the problem set and one from me :)

privetDruzia

@NeuroFuzzy well that's the part which is not clear: why is delta t=0 . Let me reread your answer, one sec

OK but why is delta t for the gas not 0? @NeuroFuzzy

NeuroFuzzy

Gas? Or ice-water phase transition?

privetDruzia

u suppose the ice melts, ie phase transition from ice to liquid. At phase transition delta t = 0.

But what about the gas? Which I think will condensate, i.e. a state transition as well

so according to what I understood from your explanations shouldn t both delta t's equal zero?

NeuroFuzzy

@privetDruzia What situation are we talking about?

Water in a container at precisely 100 degrees Celsius?

(for example)

privetDruzia

8:24 PM

@NeuroFuzzy ok

@NeuroFuzzy the situation described in the problem, i.e. a situation where you add 200g of steam to the 500g of water and 100g of ice

NeuroFuzzy

@privetDruzia Huh? You didn't mention such a problem

privetDruzia

@NeuroFuzzy physics.stackexchange.com/questions/276027/…

NeuroFuzzy

You just have to take graphs like that for granted

privetDruzia

yes I understand the graphs and know them by heart but don't know how that relates to the question I asked here: physics.stackexchange.com/questions/276027/…

@NeuroFuzzy ^

NeuroFuzzy

$T_{ice}-T_{liquid}$ is zero, because they are in thermal equilibrium, which means that the sum is zero

Haha anyways sorry, I'm taking a break from answering stackexchange questions, I was jus ttrying to answer your conceptual question you asked on chat

privetDruzia

8:31 PM

@NeuroFuzzy oh ok, because the ice and water were already in thermal equilibrium before adding the steam, we say that delta t=0?

the steam is obviously going to condensate to some extent

but some ice is going to evaporate as well and liquidify too...

NeuroFuzzy

@privetDruzia No, I was thinking of - based on what you said in chat - a situation of adding heat to a water+ice system, so that's what all of my initial comments were in reference to.

privetDruzia

@NeuroFuzzy yes I understand thx. But now as we are talking I am using that opportunity to shift our discussion topic to somewhere else, i.e. the question I posted

@NeuroFuzzy and you seem to be using that opportunity to escape :((

Bernard Meurer

9:02 PM

Hai

DanielSank

hi

I'm gunna make us a room.

Bernard Meurer

( ͡° ͜ʖ ͡°)

DanielSank

DanielSank BernardoMeurer 23 August 2016

Discussion on linear algebra and oscillations

Oh, shut up.

DanielSank

9:27 PM

@ACuriousMind we'll get to the fun stuff later.

ACuriousMind

@DanielSank oh, don't mind me, I was just looking

DanielSank

I know, just letting you know.

DanielSank

9:56 PM

@DavidZ this is just a thought about data collection meant to help, not a detraction of your efforts etc.

It might be easier to answer the questions posed in that questionnaire if each of the posts under scrutiny had been given a meta post, and each of the things we're rating on the questionnaire were an answer to the meta post. Then we'd all up/down vote each of those items.

The questionnaire is just a bit hard to navigate. It's not a big deal, and I'm not sure what I'm suggesting here would be any better.

DanielSank

10:24 PM

@DavidZ Regarding this question from your questionnaire: I would vote to close that question as asking too many questions. As usual, what is being considered from homework closure should, in my opinion, be closed for an entirely different and more specific reason.

How can I indicate this in the questionnaire or in some other useful way?

In fact, that question is an excellent example of a common pattern:

1) Show calculation
2) Ask if approach is correct
3) Ask how to proceed through math
4) Ask for alternative route of attack

These questions needs to be closed as not being focused enough.

I routinely write comments suggesting that users break up their post into multiple more focused posts.

For example, item 3) should be posted on math.SE.

So we can get rid of it outright, once the user breaks the question up.

0celo7

10:43 PM

@ACuriousMind I'm confused. If I find the eigenvalue, how do I find the eigenvector?

I'm not an algebraist

I can't solve a 2x2 system

please help

DanielSank

@DavidZ I'm not sure I like this "prior research" thing in the questionnaire. I don't really care to read about OP's conversation with colleagues and/or Google. I just want the question to stand alone as focused and easy to understand. In fact, the more I think about this whole issue, the more I think focus is an important aspect and may be lacking in many "close as homework" questions.

0celo7

the thing equals 0

what is this

DanielSank

@0celo7 Remember what I said about begging? "please help" is one of the most useless and irritating things you can post here.

0celo7

please clap

DanielSank

You get tons of help all the time by people here. You know we help when we're inclined, have time, and feel the question is interesting. "Please help" serves only to make me want to ignore you.

@0celo7 Yep, like that.

0celo7

10:49 PM

like what