posted
I remember a teacher telling me that, unlike humans, rabbits can wiggle their noses without wiggling any other part of their faces. A little while later, I actually watched a rabbit wiggle its nose, and it looked astonishingly like it was just flaring its nostrils repeatedly. Funny, I can do that too.
Posts: 1903 | Registered: Sep 2003
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quote:Originally posted by erosomniac: "You don't have the motivation to succeed, and that's not something you can obtain. You will never be successful."
I think we had the same teacher!!! This guy was my biology teacher in high school and he told me that I did not have the dedication or focus to succeed. I ended up with a PhD in plant genetics so I guess he was wrong.
I have often wondered if he told me that to try and inspire me to work harder, or if he was just a crabby burnt out teacher. He is dead so I'll never know. Posts: 514 | Registered: May 2005
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quote:Originally posted by aragorn64: Chemistry teacher: "The law of conservation of mass and energy states that they can be neither created nor destroyed."
Me: "Um, what about nuclear physics, e=mc^2, and all that stuff? Aren't they technically interchangeable?"
Teacher: "Well you are right, but since those things don't affect us we don't worry about them."
Me: "..."
This was not a silly statement from the teacher. Transformations between matter and energy can effectively be ignored for all processes that occur on this planet.
Posts: 12591 | Registered: Jan 2000
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posted
I dual enrolled through highschool, which meant that I took Freshman Comp when I was in 10th grade, or 15 years old. On the first day of class, when the teacher saw that I was in 10th grade, etc, he said, in a very ominous voice, "See me after class". So I went up after class and he said "Do you think you'll be able to handle this class? Because I don't." I responded "We'll see, won't we?". I was the only person to get an A. Heck, I was the only person in the room who had read "The Old Man and the Sea". On the last day of class I went up to him and said "Did I handle it alright?". He looked at me, smiled, and said "You did just fine".
. . .
Yesterday, in French class, we were learning about the words for family members, etc, and the teacher told us to say how Jeb Bush was related to Laura Bush. We all said "brother-in-law" and she kept on saying (in French of course) "No, husbdand. Husband!"
Posts: 2827 | Registered: Jul 2005
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quote:(AP)Monroe, NY school officials apologized after an X-rated font was used in a spelling packet handed out to parents last week.The font showed male and female stick figures in provocative poses to form the letters of the alphabet. Parents at Pine Tree Elementray School were give the packet at an open house; many parents and school officials didn't even notice the raunchy letters. Administrators said the teacher did not use the font intentionally.
quote:Transformations between matter and energy can effectively be ignored for all processes that occur on this planet.
It cannot be ignored in fission and fusion, both of which take place (at times) on this planet.
Even in fission and fusion that amount of matter converted to energy is smaller than can be measured with any common device. As a result it is resonable to assume that matter is conserved for any practical calculation even in fusion and fission reactions. Consider that converting only 1 kg of matter to energy would release 25 billion kWh of energy.
Posts: 12591 | Registered: Jan 2000
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quote:Even in fission and fusion that amount of matter converted to energy is smaller than can be measured with any common device. As a result it is resonable to assume that matter is conserved for any practical calculation even in fusion and fission reactions. Consider that converting only 1 kg of matter to energy would release 25 billion kWh of energy.
While the matter lost in fission and fusion reactions is negligible, the energy that comes from them is not.
That's where most of the energy in fission and fusion reactions comes from.
If we assume that there is no matter/energy conversion taking place, we have to assume that the energy is coming out of nowhere, which destroys the law of conservation of energy.
Posts: 16551 | Registered: Feb 2003
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posted
mph, The same thing can be said regarding chemical reactions as well. Any exothermic reaction involves matter to energy conversion but since the reduction in the matter is small enough to be negligible, it is standard practice to separate the energy balance from the material balance by including an energy term for the chemical or nuclear bonds.
This isn't silly, it is the standard way of doing energy and material balances for all processes.
Posts: 12591 | Registered: Jan 2000
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quote:That's where most of the energy in fission and fusion reactions comes from.
No, that is where all the energy comes from in all exothermic reactions. And while that is unquestionably true, its also nearly irrelevant in all real world cases.
Posts: 12591 | Registered: Jan 2000
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posted
My understanding is the same as Porteiro's.
Here's what Wikipedia says about nuclear fission, matter, and energy:
quote:The total mass of the fission products (Mp) from a single reaction, after their kinetic energy has been dissipated, is less than the mass of the original fuel nucleus. The excess mass Δm is associated with the released energy which carries it away, according to Einstein's relation E=mc˛, where the mass is Δm.
I couldn't find any similar statements in the article on exothermic reactions.
Posts: 9945 | Registered: Sep 2002
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posted
The Rabbit is right. Consider the simplest possible chemical reaction, a proton and an electron recombining to form a hydrogen atom. This reaction will emit a photon. The photon is massless, but carries away some energy; by Einstein, that energy is equivalent to mass, which must come from the electron-proton system.
Now, the other side of that is that the energy involved is on the order of electron volts, while the mass of the electron is half a million electron volts. So the loss of mass is not very noticeable, in fact I'm not sure if it's ever been measured. But it's definitely there.
Posts: 10645 | Registered: Jul 2004
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posted
In fact, I can go my last post one better by looking up the actual numbers. Mass of a proton, in u, is (by the PDG) 1.00727646688. Of an electron, 0.0005485799110. Of a hydrogen atom (careful, you want the isotope with no neutrons, not what periodic tables give for the atomic weight - that's an average) 1.00782503207. Difference between the sum of proton and electron, and the hydrogen atom: 1.4721×10^-8 u. Which works out to 13.7 eV. So I was wrong, the difference has been measured. For those of you not familiar with these kinds of units, 13.7 eV is 2.44447926×10^-35 kg. As a general rule, I'd call that pretty negligible, even when working with moles of the stuff.
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posted
The freshman english class in my old high school all ways reads Romeo and Juliet.My teacher took it upon herself to say that my class wan't able to read Shakespeare. She told me that my sister and I could read and under stand it all right, but no one else could. So the class my sister and me included read revised english translations of Shakespear. I still have not goton over the injustice.
Posts: 58 | Registered: Sep 2006
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posted
The freshman english class in my old high school all ways reads Romeo and Juliet.My teacher took it upon herself to say that my class wan't able to read Shakespeare. She told me that my sister and I could read and under stand it all right, but no one else could. So the class my sister and me included read revised english translations of Shakespear. I still have not goton over the injustice.
Posts: 58 | Registered: Sep 2006
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posted
This doesn't quite go with this topic, since this is something funny that a teacher's said, but I'll stick it in here.
APEuro Teacher: Ohio is a dirty place. Only in Ohio can a river catch on fire
APEuro Teacher: The two most popular pick up lines during the time of the Black Death: -Hey baby, got plague? And -I'll show you mine if you show me yours.
posted
"If you keep reading ahead you're going to have to stand up at your desk until you stop and follow along."
Fourth grade, we were group reading a mystery, which meant one person read aloud two-four pages and then it bounced to the next random person. If you weren't able to start reading right away if the teacher called on you, you had to stand up with your book and follow along silently and you could sit down when she next called on you and you were at the right position. Really embarassing, but eventually I was standing alot and it didn't bother me until I finished the book and went back two thirds of the book to procede at the glacial pace.
back from page one Dan_Raven said:
quote:7th Grade Science Teacher-- Cholesterol really isn't that bad for you.
Actually your science teacher wasn't silly, he was right. It's in every single cell in your body for a very good reason. Last I checked cholesterol keeps cell membranes intact, boosts mental performance, aids digestion, builds strong bones and muscle, regulates blood sugar, maintains energy, vitality, libido and fertility, repairs damaged tissue and protects against infectious disease. There's a couple dozen important hormones and steroids created during its synthesis as well. 7 dyhyrocholesterol is the precursor to vitamin D. And so on and so forth. It's one of the most important elements of your diet, not the most dangerous.
That's why your body produces four times the amount of cholesterol you can eat. it synthesizes more cholesterol when you have less of it in your diet and less cholesterol when you have more in your diet. That is why even the most strict, perfect diet cannot lower bloor serum levels more than a few percent.
high cholesterol is not dangerous, rather it either indicates another unhealthy condition--thus it acts a smoke alarm--or it may be totally innocuous. cholesterol lowering drugs--the only way to disrupt your bodies homeostatis and lower serum cholesterol levels--are like pulling the batteries out of your smoke alarm because it keeps beeping.
On the whole, your science teacher was right, Cholesterol is not that bad.
The myth that cholesterol-in-diet causes heart disease was started with experiments on herbivores (not omnivores) that lack all the digestive enzymes to process cholesterol. Most died of heart disease because the fat they couldn't excrete was layered in plaques around their arteries. Ancel Keyes (who did the herbivore (rabbit) experiments made the hypothesis that diets high in saturated fat and cholesterol causes heart disease in humans. Keyes gathered data on the % of saturated fat in diet (saturated fat being high in cholesterol) for 22 countries, and compared the data to the mortality from heart disease in those countries. He rejected the data from 16 countries because they all clearly refuted his hypothesis (we have access to all the data now, in his papers). When he published, his study only included data from 6 countries, and showed a direct correlation between high saturated fat diets and high mortality from heart disease. Had he bothered to include countries like Mexico and Finland, his hypothesis would have been shot to hell. They had the same percentage of saturated fat, 30, but the lowest and highest mortality rates from heart disease, respectively, of the 22 data points gathered.
Keyes' study caused the massive Framingham study to be performed. This is the most often cited study in cholesterol research, and the cornerstone of the high-cholesterol equals high heart disease risk. Within the text of the published study, was the conclusion that for every 1 mg/dl reduction in blood cholesterol there was an 11% INCREASE in heart disease mortality. Framingham did find that those with the rare pre-existing genetic condition called hypercholesterolemia had around a two percent increase in heart disease mortality for every mg/dl increase in serum cholesterol (iirc, they also only got this 02% conclusion by only including hypercholesterolemia subjects who had suffered or died from heart disease, excluding all the healthy people with the genetic condition from the data and conclusion, but I could misremember that). The latter finding was included in the abstract and is quoted in virtually every study or media coverage that addresses cholesterol research. The former finding--the one that applies to the general population--is never mentioned.
I had to research all this to get my only surviving grandparent off those damned deadly statins. She asked me to look into it because she'd seen too many very healthy friends and acquaintances transform from vibrant beings into sickly, frail and dying creatures when they went on Lipitor.
Posts: 128 | Registered: Aug 2006
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The point about mass/energy is that neither is globally conserved on its own. Though it's hardly obvious, the interchangeability (?!) of the two is very well understood (and measured) in pretty much every branch of physics: nuclear physics, atomic physics, general relativity, the Standard Model of particle physics, vacuum fluctuations, collider experiments, the Standard Solar Model, neutrinos, the Higgs mechanism, ad infinitum.
Posts: 105 | Registered: Oct 2005
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posted
8th grade Spanish Teacher: "I have a gun in my car. If someone comes into the school break the window open and I'll run out and get it."
8th grade U.S. History Teacher: "Don't tell me how to pronounce your name. You shouldn't care about things like that. People mispronounce my name all the time, I never correct them." I got this lecture for fiveteen minutes. Best waste of class time ever.
My seventh grade teacher and I had a running argument about which was better: Lord of the Rings or Master and Commander. I won.
Posts: 10 | Registered: Mar 2006
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posted
This teacher kept trying to tell me the first flight took place in Kitty Hawk. I kept telling her it was Kill Devil Hills, she finally believed me when I brought a map in from home.
Posts: 3134 | Registered: Mar 2005
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Physics Teacher: "Hmm...(reads it over)...I'm not sure myself. You should ask Eric."
Me: (Blinks)"...sure. I'll go do that."
Afterwhich, I got clarification from the aforementioned Eric, my fellow classmate. I probably should have done that in the first place, it being the norm. Within a day or two of the class starting, we could all tell the teacher didn't have a degree in physics and even though neither did Eric, the student knew more than the teacher. But the guy was a nice person and easy going, so no one in class wanted to mention it for fear of embarrassing him or costing him his job. (Though we speculated on how he got the position in the first place.) After that time, we just read the book, did the work, and asked each other for help when needed.
But then again, this was the same teacher that allowed me to nap on top of a lab table while he showed a film in class one day.
quote:Originally posted by Shigosei: My second grade teacher told us that "brang" was the proper past-tense form of "bring."
If only you had responded with, "I'm glad you teached me that" then waited for the response.
Your teacher was probably teaching 2nd grade for a reason Corrupt the peoples grammar while they are children, mess up the foundation.
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