Sciencemadness Discussion Board

Misconceptions in the Laboratory

Mister Junk Pile - 21-5-2011 at 22:29

Over the past few years, as I have experienced being an undergraduate chemistry student, I have noticed many misconceptions (most coming from students, of course) but many coming from teachers as well. Most of these professors, when asked about what they said (I have an open mind that I am indeed the one with the misconception I assure you; although sometimes it turns out that I am correct) will defend the apparent misconception with steadfast vigor. In fact, most of the time I am forced to stop talking and send an email to demonstrate my argument because I am cut off rather quickly. They just seem to say, "No, it's this way" and everything I say is always wrong. They are always sure they are correct without saying, "Well, I could be wrong but I have the understanding that..." This is what I would expect a reasonable person to say and indeed what I think (hope) I would say in the same position.

Most of them at least say, "Okay, go send me a reference for this". Many do not, however. They don't even consider the idea that there could be a reference that runs contrary to their beliefs.

A similar thing also happens often in class. They will give a quick response explaining why I am wrong and essentially cut me off about it. Then, I will sometimes send an email to which they will respond about 20% of the time.

It's not like this is a widespread epidemic, but I does come up from time to time. And they're not major issues, just simple things like, well, see below:

One example that consistantly comes up is the pervasive belief (or perhaps it's just an error of word usage, I can't determine exactly yet) that when one heats sulfuric acid or any reaction containing it that it is possible to "inhale sulfur trioxide fumes". Okay, I get it, but in the same way that it's possible to inhale phenoxide anions from a phenol solution at pH 3, right?

Do I have a correct understanding of this? Am I the one with the misconception that I just can't shake?

bbartlog - 22-5-2011 at 04:34

If the example you give is representative, maybe the problem is that you're being a bit of a prig? H2SO4 has some vapor pressure if you heat it (1mm @ 146C says Google). Whether the vapor is sulfur trioxide (that will turn in to H2SO4 in your lungs) or H2SO4 (that will form acidic droplets by sucking moisture out of the air, I suppose) is sort of a minor point compared to the question of whether this situation calls for some precautions on the part of the experimenter. If I made a claim such as your quote in the context of a discussion of safety and you jumped in to correct me about the *actual* composition of the fumes/vapor, I am pretty sure I'd consider you a self-important wanker. To be fair, I was just like that when I was 15.

Mister Junk Pile - 22-5-2011 at 10:16

Wow, you're a jerk. Anyone else have a non-judgmental response?

vulture - 22-5-2011 at 12:18


"Well, I could be wrong but I have the understanding that..." This is what I would expect a reasonable person to say and indeed what I think (hope) I would say in the same position.


Wow, you're a jerk. Anyone else have a non-judgmental response?

And thus it has been demonstrated that you're just as inflexible and defensive as your peers.

UKnowNotWatUDo - 22-5-2011 at 13:38

Agreed. Not to mention that when it's been years since you've actually learned the information (as in the case of your teachers) you tend to forget or remember incorrectly the facts you were taught so long ago. And that's assuming that their teacher back then had the correct information as well. Such trivial details are usually not important anyways unless you are trying to be overly cautious. I will admit I have had some experience with professors saying something when I know it to inaccurate. But in those cases it is usually either a slip of the tongue, a common brain fart, or a trivial detail with no practical relevance anyways. But no matter the reason just remember: nobody likes being corrected.

Mister Junk Pile - 22-5-2011 at 13:55

"If I made a claim such as your quote in the context of a discussion of safety"

The question about the H2SO4 was made after class. In fact, I asked three different teachers outside of class and each one gave a slightly (but significantly) different answer.

And so your argument reduces to: if someone is "nitpicky" about facts and simply wants to understand what's really happening (and wants others to understand as well) then they are a self-righteous, 15-year-old "prig" (whatever the hell that is)?

"And thus it has been demonstrated that you're just as inflexible and defensive as your peers."

Could you provide further explanation? I am inflexible because I responded to an insult with, "you're a jerk"? How does this demonstrate anything aside from the fact that I wanted to respond with "Fuck you you fucking piece of shit" and instead toned it down and asked for a more rational response that clearly confirms or denies my reasoning? HOW DOES WHAT I SAID DEMONSTRATE THAT I AM INFLEXIBLE? HE DID NOT DEMONSTRATE WHAT I SAID TO BE FALSE. The main purpose of his post was to insult and not to inform. He said absolutely nothing that my knowledge of wasn't made clear in my first post. The fact that you don't see that baffles me (or maybe you do but just don't like ANYBODY who's not caustic like you).

All this demonstrates is that he is one of the people that says, "breathing in SO3 fumes" and he got pissed that I said I thought it was a misconception. It indicates that, indeed, Bbart is, just like the people I was referring to, and unable to say, "Technically you are correct but I feel that it is a minor point". I mean, REALLY? Your reason for telling people something that is misleading is so that they will heed safety warnings? Interestingly, my understanding that this is a misconception came from my reading of one of the oleum synthesis threads.

I didn't ask whether or not it is a minor point either. It IS a minor point. That's NOT the point, obviously. You know that I knew it was a minor point but chose to say so in an apparent attempt to make it look like I didn't know it was a minor point.

Only on this board could someone come in asking a question and admitting that they could be wrong and be accused of self-righteousness in such a bitch-like manner. If it wasn't for people like Nicodem, Fleaker, 12AX7 Magpie, Polverone and woelen (and some others that I'm sure I forgot to mention) on this forum I would just say "screw it".

I just simply can't comprehend such unprovoked instigation.

I am almost embarrassed that I got such a response from the people on this forum. When it's Vulture ACTUALLY calling people stupid and insulting them, it's okay. But when I come in with wording as humble as I can possibly make it (because that's the way it really is as I have nothing but respect for all of my instructors and most of my classmates) I'm suddenly out-of-line.

Sauron has nothing on you guys. At least after you "got to know" him he could be friendly and helpful.

"But no matter the reason just remember: nobody likes being corrected."

Precisely. Except I really do believe I don't mind being corrected as long as it's not done in an insulting manner.


This explanation is so I'm not accused of backtracking. I just took out a lot of F words and toned down some insults.

[Edited on 5-22-2011 by Mister Junk Pile]

BromicAcid - 22-5-2011 at 14:18

Starting from scratch:

Yes, I agree with you that there are many misconceptions out there and that people will defend them with a certainty that is at end with their actual knowledge on the subject. In many cases this is an example of them simply not knowing better and having latched onto that truth. They don't want to give it up and will defend it however inadequately. Thus I present my own example which may or may not be wrong but is something that used to come up in my old job.

Occasionally in hazardous waste disposal we would come across a university lab where there was inevitably a small plastic jar containing picric acid stored under water. Even the people that should have known better would look at these jars containing 10 grams or so of picric acid in fear. The plastic jars they were usually in were brown and couldn't be seen through. No one on my crew wanted to open them and when they did they followed the protocol of putting the bottle in a bucket of water weighted to the bottom for a few days to get water into the threads and reduce the chance of explosion. My impression was that picric acid used to be stored in containers with metal lids, metal + picric acid = picrate salts and a potential explosion so in a plastic jar the risk just wasn't there. So I didn't have a fear of opening these bottles. But if I tried to explain this to someone they wouldn't believe me, and when a person is hard-headed about something like that it shows, and I gave up. Now to be honest I could be wrong, personally I haven't done any research into this and I don't know if I read it somewhere or made it up. I thought I was right, and so did they, so we were at an impasse.

The defensiveness seems to increase as you go up the intelligence ladder, especially if you're in a person's realm of expertise. People who see themselves as smart see themselves as infallible (at least more so than others), here is one study that found that the higher a persons education the more likely they were to fall for an investment scam. Sad but true.

With regards to the sulfuric thing, heating sulfuric acid does release fumes, weather they are SO3 or just vaporized H2SO4 is a different matter all together. Once upon a time I concentrated some sulfuric in a pan sitting on a concrete slab. The next day there was an area of dead grass 10 feet in diameter all around the pan from the 'fumes' (and likely some nice inflammation to my lungs I ignored). If it is just using the wrong words, the message is still gotten across, it's not fundamentally wrong, and personally I wouldn't argue with it since it still tells you, "Don't heat this up too high or you might get a lung full of acid", because even if the acid did dissociate at those temps (which it might, industrially the temperatures are close to 800°C but there is still going to be some action going on) and form SO3, it's going to be H2SO4 by the time it hits your lungs anyway.

Magpie - 22-5-2011 at 15:30

You have posed an interesting question, MJP. My observation is that when a person has the position and title of "teacher" in a given area of expertise, it is very hard for him to say "I don't know," or "this is what I think, but I could be wrong." This is especially true if the question is asked in front of other students. If asked in private, the above responses still bring into question the competency of the teacher. He depends on the impression of competency for his livelihood. I would like to see him answer the question honestly, but I realize that he is only human.

A story from my past employment: We were unable to control the concentration of the brine in a 5,000 gallon evaporator in a continuous process. This equipment was within my technical responsibility, so I had given it a lot of thought. One day we had a meeting to discuss the issue. My boss, the plant manager, and an operations manager, among others were in this meeting. I was asked by the plant manager what was causing this problem. I said that I had noticed that the variation followed about a 3 or 4 day cycle, and that I thought it was due to the weather. This bought out an immediate laugh of ridicule from the plant manager (a chemical engineer) and his lackeys. I didn't respond, just kept a sober face. Later he came to me and asked me to explain. My explanation was that changes in barometric pressure were affecting the boiling point in the evaporator. He walked away with a sober look on his face.

I could have made a more spirited defense in the meeting, but I like to eat and wanted to keep my job. The truth will come out eventually anyway. We then made plans to change to density control instead of bp control. My understanding is that the concentration is rock solid now.

UKnowNotWatUDo - 22-5-2011 at 15:49

Really? Nicodem was your top pick for the epitome of a friendly and well-mannered member?...Anyways, joking aside I think Magpie hit the nail on the head. Teachers are just as fallible as the rest of us but their jobs and the respect of their students depends on them always having the "right answers". That's not to say that your questions in class or after class are not valid, but like I said before most people just don't like being corrected. Especially educated people. And even if the question only IMPLIES that they MAY have been PARTIALLY incorrect about ONE thing in class.

entropy51 - 22-5-2011 at 16:30

A union steward once said to me "most supervisors don't mind being corrected, but not too often, and never in public".

Over the years I have found this to be excellent advice.

LanthanumK - 22-5-2011 at 17:25

You can also say things to the teacher in a way that would not put him/her on the defensive automatically. Asking questions in an inflammatory way definitely brings a defensive response. Try to ask it like you don't know the answer already, even if you do.

Intergalactic_Captain - 23-5-2011 at 00:11

A lot of it comes down to what type of professor you have - Is he a researcher who doesn't know how to teach, or a teacher who doesn't keep up with research? In my case, at UB, I more often than not saw the former rather than the latter. In the classroom, the students were often treated to lectures that were nothing more than a concession that was made in order to retain their research privivleges... Being that the entire science department was based on research, these are people at the top of their field that know EXACTLY what they're talking about, but they have better things to do than argue with someone that they can't relate to.

The key? Show them that you're willing to do the research to prove your point. I had a couple professors that had a love/hate relationship with me - When it came to lectures, if they said something that just didn't seem right, I'd make a note and see what the historical and recent literature said - If I found something worth saying, I'd approach them after class and make my case. Same thing with exams - O-Chem 201/202 especially. For most people, this was an "unrelated" degree requirement that they didn't care about - So they studied ONLY what was presented in the class. At the same time, I was studying more current literature and throwing different methods (whatever I was researching at the time that was relevant) into the answers - First pass at grading and I was "absolutely wrong," but after going back to the professor with a stack of journal articles pertinent to the subject it was promptly regraded...

...Long story short, if you're going to question the accepted dogma, BACK IT UP with something that will be recognized. Most educators you'll encounter will see you as nothing but a threat to the status-quo unless you can present them with something that shows elsewise. The result? Excellent recommendations and the respect of those in the field that you wish to enter...

bbartlog - 23-5-2011 at 06:31

Quote: Originally posted by Mister Junk Pile  
A similar thing also happens often in class. ...

As others have pointed out in various ways, you aren't likely to get good results by challenging someone in this kind of position publicly (and yes, they *will* perceive it as a challenge, 95% of the time).

Wow, you're a jerk. Anyone else have a non-judgmental response?

Maybe I am! Now, it does seem to me that your original post was a bit ambiguous: you ended with a question about SO3 fumes, but given the volume of associated backstory I instead read into it the question 'why does this kind of thing keep happening to me?'. I provided a possible answer. If you insist on correcting people in public, you should ask yourself whether your real priority is getting at the truth, or just promoting yourself as the smartest guy in the room.
BTW, even in cases where someone is in charge (rather than a student), it is almost always better to praise in public and correct in private. I learned this the hard way when I was supervisor of a small machine shop (part of a larger company) and had to deal with the guys taking ever-longer lunch breaks. Should have taken it up with them one at a time in my office; instead I more or less told them all off (together) and almost had them walk out of the building. Now of course they *knew* they were out of line, but once there's open conflict no one feels like they can back down without losing face.

DJF90 - 24-5-2011 at 09:39

As an interested student at school I routinely hung around at the end of class to ask my chemistry teachers questions about stuff I had read outside of the syllabus. Often they'd be unable to shine any light on the subject, but would encourage me to go and read up on it to find out - this process of self-discovery is partly what has shaped me to be who I am. Often I find myself thinking "I wonder how X is made...", and it won't be long before I'm sat at the computer or hitting the books trying to find out. Occasionally, I'll be rewarded with two types of answers; industrial manufacture and lab preparation. Most of the time I'll still dig deeper to find out if theres any routes which would be more applicable to the amateur chemist.

My teachers were out of practice when it came to alot of the university level questions I went to them with, but they were exceptionally good at teaching the course we were examined on. I think they found it quite refreshing to have such an interested and capable student for once. I was taught by one of them for 4 consecutive years - I'm sure they loved to see me grow intellectually in their chosen subject field.

With regards to recent learning, my tutors are very approachable and open to suggestions regarding explanations. On some occassions they won't know the answer, but they'll always strive to find out and send an email with what they find or wait til next class. It helps that they're up to date on the chemistry involved and are themselves practicing chemists. Often they're able to relate personal experience on how well something works (or doesn't work, as is the general case).

[Edited on 24-5-2011 by DJF90]