# Things People Learn Wrong in School?

by Bboy Physics
Tags: learn, people, school, things
P: 3,154
 Quote by sophiecentaur I'm saying that we'd need some details of this 'special' Applied Maths treatment before we could be confident about its existence. Any other treatment of friction would have to be a bit above School / College level, I think. (I'm only implying the need for evidence.)
As the person who made the original comment I wish I was able to provide that evidence but I can't. All I can remember is that one of the examining boards used was the Associated Examining Board - but can't remember if the same board was used for both Physics and Maths. I can remember the conflict was discovered in the maths class rather than the physics class.

I'm not quite willing to put it down to a false memory but who knows. It would be nice to see an old worked paper or two.
 Sci Advisor HW Helper P: 2,280 Without knowing the details, it would be impossible to know what the actual difference in approaches was. However, if you're talking about tires..... Deflating your tires increases your surface area and increases the coefficient of friction. The actual coefficient of friction is different for soft tires than for stiff tires, but I could see the increase in surface area providing a redneck estimate of the increase in the coefficient of friction, since it would be pretty difficult for the average person to determine what the new coefficient of friction was (especially since most people don't know the coefficient of friction of their tires when they're properly inflated). They may be using the wrong parameter, but they're using a parameter that tends to change at least in the same direction as the parameter they really need, but have no way of knowing. Or you have the people that realize that increasing the surface area will not increase your coefficient of friction, and so draw the even more wrong conclusion that deflating your tires cannot increase your coefficient of friction. Those will be the guys sitting in their Jeeps, stuck in the sand, waiting for a tow.
 Sci Advisor Thanks PF Gold P: 12,194 Yes - if it were as simple as that, racing cars wouldn't be swapping their tyres every half hour as conditions change.
 P: 5,462 Friction is not the only tangentiial force acting in the interaction between the road surface and a rolling pneumatic tyre. If you want a fir comparison with the theory of sliding friction (blocks) you should lock the wheels and tow the truck.
Thanks
PF Gold
P: 12,194
 Quote by Studiot Friction is not the only tangentiial force acting in the interaction between the road surface and a rolling pneumatic tyre. If you want a fir comparison with the theory of sliding friction (blocks) you should lock the wheels and tow the truck.
I think that the force would nave to be described as 'friction'. If not then you'd have to think of another name and 'friction' is a pretty catch-all term which assumes a flat surface. When would a grooved road surface become 'rails, for instance?. There again, a rubber tyre does not have linear characteristics (hysteresis and adhesion, for a start) so it wouldn't be expected to behave in an ideal way. Also, when cornering, there is slippage (work done) and the forces aren't the same as if the car were actually on rails with no slip at all.
 P: 38 The Octet Rule! I would have had a much better time in school and intro chem if I understood that it was mainly to C N O and F. I'm sure my teachers mentioned it at some point, but I never listened in highschool. Sometimes I feel like I wasn't old enough to appreciate what was being taught in highschool!
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 Quote by PeteyCoco The Octet Rule! I would have had a much better time in school and intro chem if I understood that it was mainly to C N O and F. I'm sure my teachers mentioned it at some point, but I never listened in highschool. Sometimes I feel like I wasn't old enough to appreciate what was being taught in highschool!
That's how I see a lot of people as.. but you gotta remember there are people out there who really want to learn!
 PF Gold P: 3,207 In elementary school (when I was 8) I was taught that the surface tension of water was due to gravity: Our teacher put the end of a pencil into water and removed it very slowly until it was over the surface but the water was still sticky on it. She said that it's the same force that the Moon exerts on Earth and create tides. The worst thing is that I believed her. I don't think someone had a similar experience but if you do, please post. :)
HW Helper
P: 1,987
 Quote by 0xDEADBEEF same for singers breaking wine glasses (at least it doesn't work for non defective glasses)
I think that one was more often seen a century or more ago when the average glass was a lot less perfect and had stresses in it.

I only saw it once, sitting at a restaurant table this thick glass suddenly exploded and all that was left was a fine glass powder (except for the stalk I think).
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 Quote by epenguin I think that one was more often seen a century or more ago when the average glass was a lot less perfect and had stresses in it. I only saw it once, sitting at a restaurant table this thick glass suddenly exploded and all that was left was a fine glass powder (except for the stalk I think).
Oh yes glass can do that.
 HW Helper P: 1,987 I saw in an elementary physics book which was the book set for some students I briefly taught, about hydrostatic pressure, that deep sea fish had large mouths so as to equalise pressure outside and inside them and not be crushed.
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 Quote by PeteyCoco The Octet Rule! I would have had a much better time in school and intro chem if I understood that it was mainly to C N O and F. I'm sure my teachers mentioned it at some point, but I never listened in highschool. Sometimes I feel like I wasn't old enough to appreciate what was being taught in highschool!