Scientific mistakes

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Scientific mistakes

Postby bigglesworth » Wed May 23, 2007 10:37 am UTC

Earlier today, while revising, i could not work out how to find the voltage in a fairly easy question. :idea: So i derived an equation from some other ones to get the answer. The equation i come up with? V=IR. :shock: "doh!"

any similar happenings?

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Postby skeptical scientist » Wed May 23, 2007 11:39 am UTC

NASA crashed the Mars Climate Orbiter into Mars by mixing up their units. Does that count?
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Postby Gelsamel » Wed May 23, 2007 11:45 am UTC

All the mistakes I make in calculations are always something really stupid, like I went to quick and on the 2nd last line I forgot to carry the 1, or the +c down to the next line. Or I accidentally wrote + instead of -.
"Give up here?"
- > No
"Do you accept defeat?"
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"Do you think games are silly little things?"
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"Is it all pointless?"
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Postby skeptical scientist » Wed May 23, 2007 12:00 pm UTC

I think sign errors are the bane of all physicists.

And not just physicists! (Ok, I suppose this is biophysics, but it didn't just cause problem for biophysicists, but biochemists and biologists as well.)
Last edited by skeptical scientist on Wed May 23, 2007 12:05 pm UTC, edited 1 time in total.
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Postby Spaz Funbag » Wed May 23, 2007 12:05 pm UTC

But they make it possible to fly!

@Gelsamel: What do you mean ith the "+c"?
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Postby evilbeanfiend » Wed May 23, 2007 12:12 pm UTC

more of an engineering mistake

http://www.spaceref.com/news/viewpr.html?pid=12500

iirc the accident was caused by some other team 'borrowing' some bolts that secured the satellite while it was rotated and the NOAA-N prime team neglecting to check for the presence of the bolts before tipping it.
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Postby miles01110 » Wed May 23, 2007 12:28 pm UTC

There's one university (Clarkson, maybe) that built a new library, but forgot to account for the weight of the books inside it. As a result, it's slowly sinking.

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Postby PS_Mouse » Wed May 23, 2007 12:36 pm UTC

In Physics a few years back we had this one question on a test that nobody in the class had gotten right. When I was looking at my answer after we got our papers back, I noticed that I'd done everything I was supposed to do, except add the velocity delta to the initial velocity; which would have given me the final answer. And made me the only one in the class to get the question right. :(
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Postby evilbeanfiend » Wed May 23, 2007 12:37 pm UTC

miles01110 wrote:There's one university (Clarkson, maybe) that built a new library, but forgot to account for the weight of the books inside it. As a result, it's slowly sinking.


http://www.snopes.com/college/halls/sinking.asp

every university i have ever been to has a story about one of the buildings having some massive design blunder. no doubt some of them are true, but im always wary of them.

ones ive heard before:

carpark which didn't account for weight of cars and so the top floor had a tennis court instead.

building designed to reduce wind built with plan rotated pi/2 and ended up funnelling wind

building with electronically controllable walls, which during a small fire went into default wall positions trapping people inside
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Postby PaulT » Wed May 23, 2007 12:58 pm UTC

evilbeanfiend wrote:carpark which didn't account for weight of cars and so the top floor had a tennis court instead.

I've heard exactly this too - I think in Birmingham (England as opposed to Alabama or wherever you crazy Americans have put yours). Another classic is the swimming-pool-but-forgot-to-account-for-the-weight-of-the-water.

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Postby evilbeanfiend » Wed May 23, 2007 1:08 pm UTC

PaulT wrote:
evilbeanfiend wrote:carpark which didn't account for weight of cars and so the top floor had a tennis court instead.

I've heard exactly this too - I think in Birmingham (England as opposed to Alabama or wherever you crazy Americans have put yours). Another classic is the swimming-pool-but-forgot-to-account-for-the-weight-of-the-water.


all three of mine were from the university of birmingham but i have heard almost identical stories from a fair number of other universities as well.
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Postby Maseiken » Wed May 23, 2007 1:13 pm UTC

I had a Physics test where I forgot Snell's Law, just completly dropped out of my head,
and not just that,
Refractive indices, Virtual images, all gone...

On that same test, 50% of the class had done a Diagram of a convex Mirror, as opposed to lens which was what the question was asking.
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Postby Gelsamel » Wed May 23, 2007 1:30 pm UTC

Spaz Funbag wrote:But they make it possible to fly!

@Gelsamel: What do you mean ith the "+c"?


Antidifferentiation.
"Give up here?"
- > No
"Do you accept defeat?"
- > No
"Do you think games are silly little things?"
- > No
"Is it all pointless?"
- > No
"Do you admit there is no meaning to this world?"
- > No

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Postby liza » Wed May 23, 2007 9:03 pm UTC

Gelsamel wrote:
Spaz Funbag wrote:But they make it possible to fly!

@Gelsamel: What do you mean ith the "+c"?


Antidifferentiation.


Oy. That damned constant was the bane of my life for a good while. I finally got it down to almost reflex. Though, about a month ago, I did have the following conversation:

"I don't get it. I did everything the problem told me to, but I just don't see how I can get the function to its specific form without a point on the graph. That constant is there no matter what I do!"
"Uhh, Liza?"
"Yeah?"
"You differentiated to get this function. You don't put a "+c" at the end."
*Me slinking off in an embarrassed fashion*

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Postby crazyjimbo » Wed May 23, 2007 9:26 pm UTC

I have some uncanny knack of getting the right answer, despite having numerous mistakes in my working. I guess sometimes 2 wrong signs do make a right sign :).

Of course, scientific mistakes are sometimes genius in disguise. Look at Fleming and Penicillin. Not to mention Goodyear's discovery of cement.

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Postby EvanED » Wed May 23, 2007 10:17 pm UTC

miles01110 wrote:There's one university (Clarkson, maybe) that built a new library, but forgot to account for the weight of the books inside it. As a result, it's slowly sinking.


At Penn State, the oldest still-standing building on campus is the math department's. (Though it's now been completely remodeled, and while it's very nice, I'm not sure how much of its original self remains. For instance, the stairs which used to be really deep and creek as you go up are now just typical short steps.)

A couple years ago, just before the remodeling, they supposedly brought in a contractor to study the building. Said contractor determined that the floor could not safely support the weight of the library, so when the library moved out for remodeling, it didn't come back.

I'll have to go through my old email archives and see what I can find about that.

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Postby niko7865 » Thu May 24, 2007 12:51 am UTC

They let some architecture students design one of the buildings here. It looks lovely but there is something wrong with the roof (not sure what...) and it's sinking into the ground.
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Postby darwinsbeagle » Thu May 24, 2007 3:52 am UTC

EvanED wrote:At Penn State, the oldest still-standing building on campus is the math department's.


Actually, the oldest building whose exterior has not been remodelled is Old Botany (built in 1887). McAllister, to which I believe you are referring, was built in 1904.

*end off topic*
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Postby EradicateIV » Thu May 24, 2007 4:17 am UTC

EvanED wrote: At Penn State, the oldest still-standing building on campus is the math department's.


*makes angry Pitt face*
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Postby EvanED » Thu May 24, 2007 6:27 am UTC

EradicateIV wrote:
EvanED wrote: At Penn State, the oldest still-standing building on campus is the math department's.


*makes angry Pitt face*


Oh, Pitt, from the city that doesn't even know how to spell "burg". You have to through in that extra "h". Your only redeeming quality is the Towerh ofh Learningh. ;-)

(I kid of course. I'm not one for rivalries (except for Michigan, but that's a different matter... freaking 2 second touchdown ;-)) and I have a number of indirect ties to Pittsburgh and a couple even to Pitt.)

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Postby Spaz Funbag » Thu May 24, 2007 7:38 am UTC

Gelsamel wrote:
Spaz Funbag wrote:But they make it possible to fly!

@Gelsamel: What do you mean with the "+c"?


Antidifferentiation.


What? When we learned integration, we were told "yeah there is that constant but you can just leave it" so I knew what it is, but I was surprised people actually have to write it.
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Postby EvanED » Thu May 24, 2007 8:19 am UTC

Spaz Funbag wrote:What? When we learned integration, we were told "yeah there is that constant but you can just leave it" so I knew what it is, but I was surprised people actually have to write it.


Wow, that was drilled into our heads.

Here's a picture I took of my room around the time I was taking calc (gosh, 6 years ago now it was ending? wow). Note the sheet of paper with "+ C" taped to the computer monitor as a reminder. (Note too the state of the art computers I have; those are a 286 and a 486.)

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It's not a *huge* deal when you're doing just simple stuff, but at the same time it is, because it leads to bad habits. For instance, if you are told to find 'int int 2 dx dx', the most general answer is x^2 + ax + b. But if you get into the habit of just thinking "oh, there's just a +c at the end", it's easy to overlook the middle term.

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Postby evilbeanfiend » Thu May 24, 2007 9:13 am UTC

crazyjimbo wrote: Not to mention Goodyear's discovery of cement.


i was under the impression he discovered vulcanised rubber not cement, hence the name of the tyre company.
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Postby SpitValve » Thu May 24, 2007 9:47 am UTC

EvanED wrote:It's not a *huge* deal when you're doing just simple stuff, but at the same time it is, because it leads to bad habits. For instance, if you are told to find 'int int 2 dx dx', the most general answer is x^2 + ax + b. But if you get into the habit of just thinking "oh, there's just a +c at the end", it's easy to overlook the middle term.


It matters because if you leave it out you're wrong.

There are several functions that can be differentiated to get 1. They are all of the form x+c. To say the antiderivative of 1 is just x is implying that x+1 doesn't differentiate to x, which is untrue.

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Postby Spag » Thu May 24, 2007 8:41 pm UTC

Little johnny took a drink but he will drink no more,
for what he thought was H2O was H2SO4

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Postby Syrin » Thu May 24, 2007 9:31 pm UTC

I believe its original incarnation is

Little Timmy was a chemist,
Little Timmy is no more
'Cause what he thought was H2O (aytch two oh)
Was really H2SO4 (aytch two ess oh four)

Which has a much better rhythm and flow.

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Postby djn » Fri May 25, 2007 12:34 am UTC

Syrin wrote:I believe its original incarnation is

Little Timmy was a chemist,
Little Timmy is no more
'Cause what he thought was H2O (aytch two oh)
Was really H2SO4 (aytch two ess oh four)

Which has a much better rhythm and flow.


I would drop the final "really" as well.

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Postby Syrin » Fri May 25, 2007 12:53 am UTC

So you would have 8, 7, 8, 5, instead of 8, 7, 8, 8? I dunno, I think it's much better with the 'really' still there. Up to preference, I guess.

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Postby SpitValve » Fri May 25, 2007 1:28 am UTC

I would do

Timmy was a chemist
but Timmy is no more
'cos what he thought was H20
was H2SO4

Splitting it into an segments of 4 beats, where + means "speak a syllable" and "-" means a rest:

Code: Select all

12341234
++++++-+
+++++--+
++++++++
+++++--


With emphasis on the 1s.

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Postby gmalivuk » Fri May 25, 2007 1:36 am UTC

It's not the syllables that matter, though, since English is stress timed.

This is how I learned it:

Code: Select all

 *     *      *        *
Timmy was a chemist's son

     *    *      *    *
but Timmy is no more

       *        *        * *
'cos what he thought was H20

    * * *  *
was H2SO4


The way I say it, each line now has four beats, with all but the first beginning on a pick-up before an actual stress. (Also, I learned it as a song, so the beats after the end of lines 2 and 4 correspond to sustained notes.)
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Postby djn » Fri May 25, 2007 2:37 am UTC

Syrin wrote:So you would have 8, 7, 8, 5, instead of 8, 7, 8, 8? I dunno, I think it's much better with the 'really' still there. Up to preference, I guess.


8786, I think. And yes, since it also adds up to a 4433 stress pattern (with alternating stressed/unstressed line endings), like this:

Code: Select all

v-v-v-v-  (LIttle TImmy WAS a CHEmist)
v-v-v-v   (LIttle TImmy IS no MORE,)
-v-v-v--  (cause WHAT he THOUGHT was EITCH two oh)
-v-v-v    (was EITCH two ESS oh FOUR.)

I'm also open for gmalivuk's version. (But I agree, there's no correct rythm for four lines; If you can fit a 'really' in there and it sounds good I'm not protesting.)

Oh, and for what it's worth: My chemistry lessons weren't in english, so it didn't come up there.

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Postby Vaniver » Fri May 25, 2007 4:21 am UTC

This thread is science mistakes, not rhyming mistakes.
I mostly post over at LessWrong now.

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Postby 3.14159265... » Fri May 25, 2007 5:09 am UTC

I just spent 45 minutes trying to solve this equality question, and couldn't because I copied down (1-1/n)^n, as (1+1/n)^n, damn e and 1/e.
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Postby Gelsamel » Fri May 25, 2007 5:55 am UTC

It's 'Chemist's Son'.
"Give up here?"
- > No
"Do you accept defeat?"
- > No
"Do you think games are silly little things?"
- > No
"Is it all pointless?"
- > No
"Do you admit there is no meaning to this world?"
- > No

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Postby gmalivuk » Fri May 25, 2007 3:31 pm UTC

Gelsamel wrote:It's 'Chemist's Son'.


Indeed. And it's also Johnny, apparently. In hindsight that sounds more familiar to me than Timmy.
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Postby evilbeanfiend » Fri May 25, 2007 3:41 pm UTC

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Postby TheTankengine » Fri May 25, 2007 5:07 pm UTC

Spaz Funbag wrote:
Gelsamel wrote:
Spaz Funbag wrote:But they make it possible to fly!

@Gelsamel: What do you mean with the "+c"?


Antidifferentiation.


What? When we learned integration, we were told "yeah there is that constant but you can just leave it" so I knew what it is, but I was surprised people actually have to write it.


I love it when teachers simplify concepts to the point that it is no longer correct.

No, wait, I hate that.
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Postby fabu » Sat May 26, 2007 10:26 am UTC

TheTankengine wrote:
Spaz Funbag wrote:
Gelsamel wrote:
Spaz Funbag wrote:But they make it possible to fly!

@Gelsamel: What do you mean with the "+c"?


Antidifferentiation.


What? When we learned integration, we were told "yeah there is that constant but you can just leave it" so I knew what it is, but I was surprised people actually have to write it.


I love it when teachers simplify concepts to the point that it is no longer correct.

No, wait, I hate that.


In a math test about a year ago, i forgot the +c and therefor, i only got 14 points instead of 15 which is A+ in Germany.
And since Spaz Funbag is at my school, i can't believe he was told that the +c would be not important. Probably in his dreams ;)

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Postby bippy » Sun May 27, 2007 12:47 am UTC

A few years ago I was waiting in a doctor's office for what seemed like forever so I started scribbling down Maxwell's relations and just making up systems to solve. In one of them I ended up getting something like some term was equal to its opposite. (And of course I know that can happen when both are zero but that wasn't assumed anywhere.) I was so puzzled by the result I saved the scrap of paper I was writing on and took it home to look at it. I figured out where I had made my mistake and that was that.

Rather than tossing it out, it found its way into a drawer of mine. A few years later I found it and saw the circled result and was puzzled all over again. I didn't immediately remember what it was from but as I began re-working it and following my steps I recalled where it came from and the whole thing from before.

I have it in my drawer right now, so maybe in a few years I will find it again and either remember or not. But it's one heck of a way to keep Maxwell's relations fresh in your mind.

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back in the good old days

Postby Gurkha » Tue May 29, 2007 11:01 pm UTC

When I was a first year undergrad, we had a question about electrostatic forces. Formula: kQq/(r^2)
At this point, I was still thinking like a A-level student and, rather than use 1/(4 pi ep0) for k, I went to my formula booklet and got, well, k. The problem was, of course that the k in the formula booklet was Boltzmann's constant, and not the constant for the electrostatic force equation and my answer was ~ 36 orders of magnitude out. Oops. My tutor group laughed at me, erm, quite a lot.


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