About teachers..

[misterT]

When I was around 15 years old my math teacher asked: "if you stretch a ruler, does it show more or less than what is correct". After a long debate I had to give up because she was the principle of the school.. she said that the ruler shows more.

Another thing that bothers me was when my physics teacher said: "circular motion is unnatural". If you look at planets etc. they are all at circular path.. actually it is pretty hard to get something to go absolutely straight. Even light bends because of gravitation and refraction.

Sorry if my english is not correct.. blame it to my teacher

 

[Ian Rogers]

she said that the ruler shows more.

Surely that depends on which way you bend it.... If you bend it on the side of the scale less... the other side will be more!!

 

[dougy83]

When I was around 15 years old my math teacher asked: "if you stretch a ruler, does it show more or less than what is correct". After a long debate I had to give up because she was the principle of the school.. she said that the ruler shows more.

You're a teacher/lecturer now, right? So now you get to do the same thing to students

Another thing that bothers me was when my physics teacher said: "circular motion is unnatural". If you look at planets etc. they are all at circular path.. actually it is pretty hard to get something to go absolutely straight. Even light bends because of gravitation and refraction.

Do you mean that planets have elliptical paths?

Sorry if my english is not correct.. blame it to my teacher

Your English is better than most English speakers. Blame that on our students.

 

[tvtech]

OMG!!! Innocently I Googled this: Ruler Stretch Video

The results thereof cannot be posted here....hence no link.

The very last thing I expected

Regards,
tvtech

 

[JimB]

Sorry if my english is not correct.. blame it to my teacher

I am blaming your teacher!
It would be better to say "blame it ON my teacher"

One of the big problems with teachers is that most of them have only known the academic environment.
They went to school.
They went to teacher training college / university.
And now they are back in school/college/university.
No experience of how the real world works.

JimB

 

[tvtech]

Hi Guys

One only sees this as Jim says in the "real world". No amount of theoretical Training can do that...

Hard but true road. All the Theory will not save you if you ain't been there with real stuff happening...and someone experienced helping you along and keeping you safe at the same time...

I have seen way too many accidents due to careless things being done......favourite:....suddenly a pair of Sidecutters are useless. Don't cut anymore.
Check them out....two holes burnt where somebody cut through Live Mains with them...

Not even EHT...just people being careless. The Human Race has incredible inbuilt stupidity at times.

I am too old for nasty stuff now. I think thrice (3X) these days. And good for me.

Stay well Jim

tvtech

 

[NorthGuy]

Check them out....two holes burnt where somebody cut through Live Mains with them...

Done that. Part of the experience ...

 

[KeepItSimpleStupid]

So, if you stretch a ruler, it's the same mass: Question is very ambiguous.

Circular Motion: A sundial

 

[tvtech]

This thread is all stuffed up. Completely off the rails...

Than I looked and saw it was me that did it

Sorry Folks

Regards,
tvtech

 

[NorthGuy]

After a long debate I had to give up because she was the principle of the school..

The most important principle of any school is that the principal is always right

 

[RichTheDude]

When I was about 15 I designed and built a crystal set for a physics coursework to demonstrate tuned circuits (point contact diode, jackson variable capacitor and a coil rolled on a toilet roll).

My teacher refused to even TRY it, as it was "impossible" for such a radio to work without amplification. I described that I had a pair of high impedance earphones (a few k Ohm, brought from a radio rally), but he was having none of it. Anyway, I used a water pipe as an earth and chucked some wire out of the class window as an aerial and got it working.

He was astonished and decided to go and look up crystal sets, just in case I hid some transistors in there for his beloved amplification theory. Anyway, he later apologised to me. The biggest problem with school teachers is that they are career teachers (I have a similar grudge against career politicians). Push them out of their comfort zone, and they break down as they do not have enough experience or knowledge gained from working in industry or real life.

Most of my school teachers was awful (apart from one old guy who taught me engineering, he worked at Ford UK and GKN as a designer before becoming a teacher). At college and university (teachers typically >= 50 years old rather than <40), the knowledge and understanding of my lecturers was orders of magnitude better - as most of them had real jobs before getting an "easier" job as they called it in academia.

 

[KMoffett]

...
Most of my school teachers was [were] awful (apart from one old guy who taught me engineering, he worked at Ford UK and GKN as a designer before becoming a teacher). At college and university (teachers typically >= 50 years old rather than <40), the knowledge and understanding of my lecturers was [were] orders of magnitude better - as most of them had real jobs before getting an "easier" job as they called it in academia.

Perhaps they felt that way about some of their students.

Ken

 

[edeca]

Perhaps they felt that way about some of their students.

Your second correction is inaccurate. How ironic.

 

[JimB]

When I was about 15 I designed and built a crystal set for a physics coursework to demonstrate tuned circuits (point contact diode, jackson variable capacitor and a coil rolled on a toilet roll).
My teacher refused to even TRY it, as it was "impossible" for such a radio to work without amplification. I described that I had a pair of high impedance earphones (a few k Ohm, brought from a radio rally), but he was having none of it. Anyway, I used a water pipe as an earth and chucked some wire out of the class window as an aerial and got it working.
He was astonished

That is so sad and most perturbing on many levels.

decided to go and look up crystal sets, just in case I hid some transistors in there for his beloved amplification theory. Anyway, he later apologised to me.

That I am glad to hear, especially the apology bit.

One of our electrical engineering lecturers had worked in British Railways Engineering Dept before turning to teaching, one informal bit of wisdom which he imparted to one of his brash students (me ) was

"If you don't understand how it works, however do you expect to control it?"
Over the years I have adapted this to:
"If you don't understand how it works, however do you expect to repair it?"
"If you don't understand how it works, however do you expect to operate it correctly?"

The guy was correct! Thank you Mr Fairbrother.

JimB

 

[NorthGuy]

"If you don't understand how it works, however do you expect to repair it?"

I repair many things (and it seems to be more and more with time). Usually I don't know how the broken thing works, but I find this out in the process of repairing. It would be very boring otherwise.

Often I don't expect I can do a repair, I just want to look inside, but then I find out that it's not that bad actually, and I often succeed.

 

[KMoffett]

Your second correction is inaccurate. How ironic.

"...the knowledge and understanding of my lecturers was...."
...the knowledge was...
...[the] understanding was...
...the knowledge and understanding "were"
Ken

 

[steveB]

After a long debate I had to give up because she was the principle of the school.. she said that the ruler shows more.

You were correct to give up the debate, but you should not have given up completely. The answer was simply to build a stretchable ruler and prove it to her.

 

[JimB]

I repair many things (and it seems to be more and more with time). Usually I don't know how the broken thing works, but I find this out in the process of repairing.

This is also the case sometimes.
Maybe I should qualify my statement
"If you don't understand how it works, however do you expect to repair it?"
by saying that when you are responsible for maintaining a complex piece of equipment in an industrial setting, if you are going to fix it in a timely manner, you have to understand how it works.

Having said that, sometimes you are presented with a bit of equipment which you have never seen before and dont even know what it does, let alone understand it, and you are the man, you have to fix it, there is no one else.
I was once in that situation, and wow did I get lucky!
The "thing" was about the size of PC mini-tower, it was a nuclear radiation counting thing in a lab, it just sat there doing nothing, and they needed it working ASAP.
I had never seen it before and we had no spares.
It was full of circuit boards (about A4 paper size) and those circuit boards were full of TO5 sized transistors.
So I thought that I would look for bad solder joints.
I took out each board in turn and ran may finger along all the components to feel for something loose.
Eventually, I found one of the TO5 transistors that wiggled a bit, it had a broken solder joint on one of its legs.
So I re made all the joints on that transistor, put it all back together and it worked.
The force was definitely with me that day.

The best part about it is, out of the 100s of transistors in that thing, the one which was loose had been changed at some time in the past, none of the others, only that one, and the guy who did it did a poor job of the soldering!

JimB

 

[KeepItSimpleStupid]

Yea, I remember those days f troubleshooting. I could not operate the equipment, an Auger Spectrometer, but I had to ask a series of questions to remote be able to fix it.

At a later time, one part of that machine lost one of the color drive signals. Sine the board was wire-wrapped (TTL logic) from the factory, I really did have a slim chance of finding the problem.
It turned out the problem was a connection to the power pin of a 7400 series IC that was not soldered to the board. Only the power pins were soldered. The rest were wire-wrapped.

That machine had lots of modular parts by various vendors. Part Scanning Electron Microscope, Part vacuum systems from roughing, turbo and ion pumps. A mass spec and ion milling. It was controlled by a Micro PDP-11. The PDP-11 part was easy.

Now, the number of cables running around was something else.

 

[Pommie]

When I was around 15 years old my math teacher asked: "if you stretch a ruler, does it show more or less than what is correct". After a long debate I had to give up because she was the principle of the school.. she said that the ruler shows more.

If you stretch a 12" rule to 15" then it will measure a 15" piece of steel as 12". The rule shows less than the real length - real length 15" is less than the reading on the rule of 12". How can anyone argue the opposite?

Mike.