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Author Topic: Bang Your Head on Your Desk - the thread of teaching despair!  (Read 2038412 times)
polly_mer
practice makes perfect
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Have you worked on that project today?


« Reply #5520 on: March 22, 2012, 9:54:17 AM »

Or perhaps, I should be more concerned that apparently, getting anxious during exams count as a disability?

I've only been teaching a few years as a grad student, but I see more and more of these, particularly in large lecture classes, at my university. Exam anxiety apparently does count as a disability for some, and they must be given the chance to take the exam in total silence, in a room by themselves, and with twice the allotted time. One insisted that she be allowed to have a snack and a juice box while writing her exam and that it was part of her disability accommodations as well. I assume one of her symptoms is dry mouth or something like that, but the whole thing felt a little strange.
I have no problem with accommodations as long as they are registered with the disability office.  I expect that office has rules and guidelines to determine such.  This actually works out better for me as students then have the option of taking exams in their facilities since they get time and a half.  It's the idea that somehow this is something they can just claim and they'd get accommodated that bothers me.  Of the 4 students who came in to see me, only one actually admitted he was not doing the required work.  The other 3 all claim they get anxious and asked if they can get extra time!

Send those students straight to the disabilities office!  Either they will get the help they need or they will get a firm lecture on not being whiners, at least that's true at our disabilities office.
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I've joined a bizarre cult called JordanCanonicalForm's Witnesses.  I have to go from door to door asking people things like, "Good evening, sir!  Do you have a moment to chat about Linear Transformations?"
dr_evil
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« Reply #5521 on: March 22, 2012, 10:05:54 AM »

And if the learner intended recipient of said knowledge is not engaged, it's OUR fault. We didn't inspire/motivate/captivate/entertain/stimulate them enough.

You don't sound learner-centered, my embittered amigo. You may require some professional indoctrination development training.

Do we work at the same place?

As for all the sigfig talk, I too am having trouble explaining the difference between 100 g and 100.0 g.  We should not be having these issues this far into the semester.  Haven't we been applying these rules all term?  (Well, some of us have.)
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Wheeeeee! You go, oh evilicious one.
polly_mer
practice makes perfect
Distinguished Senior Member
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Posts: 37,443

Have you worked on that project today?


« Reply #5522 on: March 22, 2012, 10:18:41 AM »

As for all the sigfig talk, I too am having trouble explaining the difference between 100 g and 100.0 g.  We should not be having these issues this far into the semester.  Haven't we been applying these rules all term?  (Well, some of us have.)

Do you know how pleased I would be to only be having that talk?  Instead, as of last week, I was still having the talk that goes something like  45892.2 m does not round to 45 m, 45000.000 m, 44000 m or 5.0000*10^4 m.  What some of these students have taken from the lessons on sig figs and scientific notation and made into rules makes my head spin.  I didn't tell them that and I can't believe any of my colleagues told them that.  Why? 
Logged

I've joined a bizarre cult called JordanCanonicalForm's Witnesses.  I have to go from door to door asking people things like, "Good evening, sir!  Do you have a moment to chat about Linear Transformations?"
dr_evil
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Posts: 6,286


« Reply #5523 on: March 22, 2012, 10:39:09 AM »

As for all the sigfig talk, I too am having trouble explaining the difference between 100 g and 100.0 g.  We should not be having these issues this far into the semester.  Haven't we been applying these rules all term?  (Well, some of us have.)

Do you know how pleased I would be to only be having that talk?  Instead, as of last week, I was still having the talk that goes something like  45892.2 m does not round to 45 m, 45000.000 m, 44000 m or 5.0000*10^4 m.  What some of these students have taken from the lessons on sig figs and scientific notation and made into rules makes my head spin.  I didn't tell them that and I can't believe any of my colleagues told them that.  Why? 

Ouch.  It makes my brain hurt.  I haven't had any quite that bad.  Well, at first they would have rounded 45892.2 m to 45 m, but even my most struggling student has gotten past that.  I feel lucky now.
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Wheeeeee! You go, oh evilicious one.
cc_alan
is a wossname
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Caution! Nekkid Zamboni driver ahead.


« Reply #5524 on: March 22, 2012, 1:25:20 PM »

And if the learner intended recipient of said knowledge is not engaged, it's OUR fault. We didn't inspire/motivate/captivate/entertain/stimulate them enough.

You don't sound learner-centered, my embittered amigo. You may require some professional indoctrination development training.

Do we work at the same place?

As for all the sigfig talk, I too am having trouble explaining the difference between 100 g and 100.0 g.  We should not be having these issues this far into the semester.  Haven't we been applying these rules all term?  (Well, some of us have.)

"We" (I put it in quotes because sometimes it feels like the only part of "we" that's listening is "me") have a big discussion about the balance and about how one should always write the mass to three decimals because our balances read to the nearest milligram and...

<insert loud, scary, thunderous voice>

THOU SHALT NOT ROUND DATA!

If the mass is 50.000 g then you dang well better write 50.000 g. I'll repeat-

<insert loud, scary, thunderous voice>

THOU SHALT NOT ROUND DATA!

Most students get it but I still have a few in the last half of the term who struggle with how to write the mass and how many decimals to use when subtracting masses (say, final mass - initial mass). These students, the ones who struggle with how to record masses as read from the balance, usually are doing very poorly, overall, in the course.

Alan
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Guess what? I got a fever and the only prescription is MORE COWBELL!
genius_at_large
Wylie E. Coyote, Genius at Large
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« Reply #5525 on: March 22, 2012, 4:40:11 PM »

Patron Saint of the Snowflakes has missed a third class now (unexcused) in a class that only meets once a week. When he does show up, he insists on behaving as if he's still in middle school. Looks like we'll be able free up some more scholarship money for next semester if he doesn't shape up fast.
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I'm just a peckerwood who lives in the hills with too many guns.
mystictechgal
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One step at a time


« Reply #5526 on: March 23, 2012, 12:28:02 AM »

And if the learner intended recipient of said knowledge is not engaged, it's OUR fault. We didn't inspire/motivate/captivate/entertain/stimulate them enough.

You don't sound learner-centered, my embittered amigo. You may require some professional indoctrination development training.

Do we work at the same place?

As for all the sigfig talk, I too am having trouble explaining the difference between 100 g and 100.0 g.  We should not be having these issues this far into the semester.  Haven't we been applying these rules all term?  (Well, some of us have.)

"We" (I put it in quotes because sometimes it feels like the only part of "we" that's listening is "me") have a big discussion about the balance and about how one should always write the mass to three decimals because our balances read to the nearest milligram and...

<insert loud, scary, thunderous voice>

THOU SHALT NOT ROUND DATA!

If the mass is 50.000 g then you dang well better write 50.000 g. I'll repeat-

<insert loud, scary, thunderous voice>

THOU SHALT NOT ROUND DATA!

Most students get it but I still have a few in the last half of the term who struggle with how to write the mass and how many decimals to use when subtracting masses (say, final mass - initial mass). These students, the ones who struggle with how to record masses as read from the balance, usually are doing very poorly, overall, in the course.

Alan

Interesting. Our scales go to three decimals, too, but I've lost points for using them. Many of the directions for labs specify the use of tenths or hundredths, which we then round to, and regardless of how specific our measuring techniques might be the final answer contains no more figures than the least of any of the numbers used in the calculation. That's sometimes problematic when working end of chapter problems when, for instance, the fewest figures used in one of the givens is two, I get an answer of, say, 0.0654 and convert it, as taught, to 6.4 x 10^-2 only to find that the answer given in the back of the book is 0.0654.
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Quote
You must realize that a university cannot educate you. You must do that for yourself, although a college or university is the place where it is likely that you can study most efficiently.
http://www.lhup.edu/~dsimanek/chapman.htm

"Is all the same, only different" -- HL
cc_alan
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Posts: 9,563

Caution! Nekkid Zamboni driver ahead.


« Reply #5527 on: March 23, 2012, 1:30:15 AM »

Interesting. Our scales go to three decimals, too, but I've lost points for using them. Many of the directions for labs specify the use of tenths or hundredths, which we then round to, and regardless of how specific our measuring techniques might be the final answer contains no more figures than the least of any of the numbers used in the calculation. That's sometimes problematic when working end of chapter problems when, for instance, the fewest figures used in one of the givens is two, I get an answer of, say, 0.0654 and convert it, as taught, to 6.4 x 10^-2 only to find that the answer given in the back of the book is 0.0654.

The bolded part sounds like a simple incompatibility between the instructions and the equipment. Are you using a publisher's lab manual or are you using a "home-brew" lab manual? In one of the labs I teach we use a publisher's lab manual and I make a few corrections/additions to the instructions at the start of each lab to reconcile the differences between our lab's equipment and that assumed by the lab manual.

I obviously don't know your lab setup but I'm scratching my head as to why you would lose credit for properly recording a mass from the balance. It's possible that the difference is coming from a later calculation. Have you asked your lab instructor about it? If you've lost credit for simply recording a balance reading to 3 decimals, I suggest asking your lab instructor to explain. If it's "because that's what the instructions say" then you could push it or write it in your evaluation of the lab instructor. I guarantee that if an evaluation came back where I work with a reasoned description as to how the lab instructor is following incorrect lab manual instructions just "because", the chair would at least inquire about it.

I've had that battle with an instructor when it came to incorrect information in the textbook. This coworker would use something incorrect from the book even though that person knew it was wrong. When I asked for the reason, it was something along the lines of "not wanting to confuse the students by telling them something different."

<insert head-banging moment>

As for the calculation differences, this could be due to any number of reasons-

1. The answer in the book is wrong.
2. You are confusing the significant figure rules for addition/subtraction with multiplication/division.

As to my reason #2 and using your answer-

0.0654 has three significant figures as written but four decimal places. 0.065 or 6.5x10^-2 has three decimals but 2 significant figures. If the final answer is supposed to have three decimals then 0.065 is correct (say, the addition/subtraction rule). If the final answer is supposed to have three significant figures then 0.0654 is correct.

Alan
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Guess what? I got a fever and the only prescription is MORE COWBELL!
conjugate
Compulsive punster and insatiable reader, and
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Tends to have warped sense of humor


« Reply #5528 on: March 23, 2012, 10:49:14 AM »


I obviously don't know your lab setup but I'm scratching my head as to why you would lose credit for properly recording a mass from the balance. It's possible that the difference is coming from a later calculation. Have you asked your lab instructor about it? If you've lost credit for simply recording a balance reading to 3 decimals, I suggest asking your lab instructor to explain. If it's "because that's what the instructions say" then you could push it or write it in your evaluation of the lab instructor. I guarantee that if an evaluation came back where I work with a reasoned description as to how the lab instructor is following incorrect lab manual instructions just "because", the chair would at least inquire about it.


If some other numbers involved in the computation are available only to one or two significant figures, then possibly the lesson being taught is that all the numbers involved should have about the same level of precision.

Suppose I measure, say, the radius of a circle to the nearest cm, and use an approximation of pi to (say) 5000 digits to compute the circumference or area.  Obviously, I can't expect 5000 digits of precision in the result.  It may be that the lab instructor is trying to emphasize this by counting off for students who use higher precision in one measurement than is available in another measurement.

Mind you, it sounds pretty silly to me, but then I don't deal with numbers that represent reality in any sense.  I only rarely tell my students to write "units" or "square units" after problems that involve finding lengths or areas when units aren't specified, because I don't think in those terms much myself.
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Unfortunately, I think conjugate gives good advice.
∀ε>0∃δ>0∋|xa|<δ⇒|(x)-(a)|<ε
cc_alan
is a wossname
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Caution! Nekkid Zamboni driver ahead.


« Reply #5529 on: March 23, 2012, 11:08:46 AM »


I obviously don't know your lab setup but I'm scratching my head as to why you would lose credit for properly recording a mass from the balance. It's possible that the difference is coming from a later calculation. Have you asked your lab instructor about it? If you've lost credit for simply recording a balance reading to 3 decimals, I suggest asking your lab instructor to explain. If it's "because that's what the instructions say" then you could push it or write it in your evaluation of the lab instructor. I guarantee that if an evaluation came back where I work with a reasoned description as to how the lab instructor is following incorrect lab manual instructions just "because", the chair would at least inquire about it.


If some other numbers involved in the computation are available only to one or two significant figures, then possibly the lesson being taught is that all the numbers involved should have about the same level of precision.

But that question is whether it's a measurement or a computation. If someone is writing down a mass measurement and the balance reads to 1, 2, or 3 decimals, then regardless of what the instructions say the mass measurement needs to be written according to the instrument. Otherwise you've lost the ability to recover your original data.

*Data* is not rounded.

Alan
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octoprof
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Love your loved ones while you can.


WWW
« Reply #5530 on: March 23, 2012, 11:17:39 AM »

But that question is whether it's a measurement or a computation. If someone is writing down a mass measurement and the balance reads to 1, 2, or 3 decimals, then regardless of what the instructions say the mass measurement needs to be written according to the instrument. Otherwise you've lost the ability to recover your original data.

*Data* is not rounded.

Alan

I love this post. I can't seem to get my cost accounting students to understand that all that crazy rounding they do results in very inaccurate numbers. And, those numbers are meant to be used to make decisions. So, maybe, having more accurate results, might be a good idea, eh? 

They seem to think calculations of costs should only have two decimal places because they are dollars...

<bangs head on desk>
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cc_alan
is a wossname
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Caution! Nekkid Zamboni driver ahead.


« Reply #5531 on: March 23, 2012, 11:22:50 AM »

But that question is whether it's a measurement or a computation. If someone is writing down a mass measurement and the balance reads to 1, 2, or 3 decimals, then regardless of what the instructions say the mass measurement needs to be written according to the instrument. Otherwise you've lost the ability to recover your original data.

*Data* is not rounded.

Alan

I love this post. I can't seem to get my cost accounting students to understand that all that crazy rounding they do results in very inaccurate numbers. And, those numbers are meant to be used to make decisions. So, maybe, having more accurate results, might be a good idea, eh? 

They seem to think calculations of costs should only have two decimal places because they are dollars...

<bangs head on desk>

Office Space! Siphon-off those "unneeded" decimal places and let's party!

<insert more exclamation points>

Alan
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Guess what? I got a fever and the only prescription is MORE COWBELL!
octoprof
Member-Moderator
Distinguished Senior Member
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Posts: 45,172

Love your loved ones while you can.


WWW
« Reply #5532 on: March 23, 2012, 11:24:50 AM »

But that question is whether it's a measurement or a computation. If someone is writing down a mass measurement and the balance reads to 1, 2, or 3 decimals, then regardless of what the instructions say the mass measurement needs to be written according to the instrument. Otherwise you've lost the ability to recover your original data.

*Data* is not rounded.

Alan

I love this post. I can't seem to get my cost accounting students to understand that all that crazy rounding they do results in very inaccurate numbers. And, those numbers are meant to be used to make decisions. So, maybe, having more accurate results, might be a good idea, eh? 

They seem to think calculations of costs should only have two decimal places because they are dollars...

<bangs head on desk>

Office Space! Siphon-off those "unneeded" decimal places and let's party!

<insert more exclamation points>

Alan

<cackles!>

They just can't get that when you round off those "unneeded" decimal places and then multiple that cost-per-unit by 2,000,000 units... the results are pretty much crap.
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Love your neighbor.
galactic_hedgehog
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Mind Ninja


WWW
« Reply #5533 on: March 23, 2012, 11:36:50 AM »

Interesting. Our scales go to three decimals, too, but I've lost points for using them. Many of the directions for labs specify the use of tenths or hundredths, which we then round to, and regardless of how specific our measuring techniques might be the final answer contains no more figures than the least of any of the numbers used in the calculation. That's sometimes problematic when working end of chapter problems when, for instance, the fewest figures used in one of the givens is two, I get an answer of, say, 0.0654 and convert it, as taught, to 6.4 x 10^-2 only to find that the answer given in the back of the book is 0.0654.

The bolded part sounds like a simple incompatibility between the instructions and the equipment. Are you using a publisher's lab manual or are you using a "home-brew" lab manual? In one of the labs I teach we use a publisher's lab manual and I make a few corrections/additions to the instructions at the start of each lab to reconcile the differences between our lab's equipment and that assumed by the lab manual.

I obviously don't know your lab setup but I'm scratching my head as to why you would lose credit for properly recording a mass from the balance. It's possible that the difference is coming from a later calculation. Have you asked your lab instructor about it? If you've lost credit for simply recording a balance reading to 3 decimals, I suggest asking your lab instructor to explain. If it's "because that's what the instructions say" then you could push it or write it in your evaluation of the lab instructor. I guarantee that if an evaluation came back where I work with a reasoned description as to how the lab instructor is following incorrect lab manual instructions just "because", the chair would at least inquire about it.

It could also be due to an instructor who doesn't know the proper rules of rounding.  Perhaps that person thinks that you round all number to, say, two digits before calculations, instead of after.
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ellaminnowphd
Curiously Strong
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Posts: 3,824


« Reply #5534 on: March 23, 2012, 11:47:12 AM »

Apparently when I was in elementary school (I don't remember this, it's my mom's story) I told my teacher that what was wrong with the world was that everyone rounded up.  My teacher was amused enough to call my mom. 
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