Verbal Aids for Science (Mottos)

[joigus]

We're all  familiar with how certain concepts in science are difficult to grasp, or perhaps to remember.

Mottos are these pieces of wisdom that try to capture an idea and make it easier to grasp yourself, or to get across to others through an intuitive verbal formulation.

Some of them can be quite unfortunate. They shall not be mentioned here, if possible.

So my suggestion is: Let's all share those brief phrasings that have helped us remember an idea, understand it better, keep it closer to our hearts and brains. They can be our own creation or found elsewhere and treasured ever since. 

One example could be (these are my own):

"Velocity is the parameter which tells you what time and space directions you're looking at when you're moving" (special relativity)

Or:

"A tensor is a product of projections of physical quantities; different observers see different projections; but if they knew the rules of rotation, they would all relate their data and say: 'Oh, we're all seeing the same thing!'" (general relativity, tensor calculus)

I invite you all to share brief formulas like these that you've found useful to capture an idea, whether you've devised them yourselves or you've found them somewhere else and retained them as useful conceptual tools. Keep in mind that the more rigorous you try to be, the less memorable the motto.

If you don't like mine, feel free to tell me. All science areas welcome.

 

Edited August 18, 2020 by joigus
minor modification

[studiot]

A worth topic sir.  +1

 

Input  =  Output  +  Accumulation

[dimreepr]

It doesn't seem to change the need for rigor, while leaving the less rigorous an invite too join in; a dear wish of mine is to play a musical instrument, but I've yet to receive an aphorism that by-passes the need to practice...

[joigus]

13 minutes ago, dimreepr said:

It doesn't seem to change the need for rigor, while leaving the less rigorous an invite too join in; a dear wish of mine is to play a musical instrument, but I've yet to receive an aphorism that by-passes the need to practice...

That reminds me of Matrix. One of those drives you could download all your knowledge from. Even practical knowledge. Tensor calculus in 5 seconds. Helicopter piloting in 3. That would be nice.

1 hour ago, studiot said:

A worth topic sir.  +1

 

Input  =  Output  +  Accumulation

Thanks. I knew you would appreciate it. Let's see if people can provide some good ideas. Let's see if it arouses some interest. I hope so.

[zapatos]

First two laws of Thermodynamics: 

1. You can't get something for nothing

2. Even at best you can't break even

(Hope I remembered that correctly! 😄)

[joigus]

10 minutes ago, zapatos said:

First two laws of Thermodynamics: 

1. You can't get something for nothing

2. Even at best you can't break even

(Hope I remembered that correctly! 😄)

LOL. That's a good one. Or two. +1

1 hour ago, studiot said:

Input  =  Output  +  Accumulation

Sorry, is it meant to be Input = Output + Accumulation or Output = Input + Accumulation?

Edited August 18, 2020 by joigus

[studiot]

1 hour ago, zapatos said:

First two laws of Thermodynamics: 

1. You can't get something for nothing

2. Even at best you can't break even

(Hope I remembered that correctly! 😄)

As I recall it goes like this

 

The First Law states that you can't win you can only break even.

The Second Law states that you can't break even.

[Strange]

2 hours ago, studiot said:

Input  =  Output  +  Accumulation

In what context? I am trying to get my head round what that means!

My contribution: "Are photons particles or waves? Neither: they are photons"

[MigL]

The Laws of thermodynamics had a 'gambling' analogy.

You can't win.
You can't break even.
The third was...
And you can't get out of the game.

[joigus]

Well, we've got thermodynamics, SR, GR, algorithms, and QM, off to a good start. Pending some clarification on algorithms. This looks promising.

[Dord]

 

waves/particle/fields are not what these thing are, they are just how we describe them.

The map, not the country.

 

(With thanks to @Strange )

 

[MigL]

12 minutes ago, Dord said:

waves/particle/fields are not what these thing are, they are just how we describe them.

The map, not the country.

Corollary to this...

Theories are not reality; They just describe (some aspects of ) reality.
Models, not the 'real thing'.

[Dord]

These are police expressions but seem equally relevant to all inquisitive professions:

 

Absence of evidence is not evidence of absence.

 

ABC - the detectives' mantra

Accept nothing (on face value)

Believe nothing (without independent corroboration)

Challenge Everything (with reasonable lines of enquiry)

 

ABC - radio comms & report writing 

Accurate

Brief

Clear

[studiot]

16 hours ago, Strange said:

In what context? I am trying to get my head round what that means!

 

 

17 hours ago, joigus said:

Sorry, is it meant to be Input = Output + Accumulation or Output = Input + Accumulation?

Input = Output + Accumulation is correct.

I learned this one because my first year flatmate mumbled it every day for a year and came top in Chemical Engineering.
He said it was the only thing he learned for the exams and covered eeverything, which is not far from the truth.
It is a general flux formula for momentum, mass energy etc.

Some more from the time when formulae were not hidden by apps.

The surveyors mantra

[math]\frac{{{{\left( {{\rm{something}}} \right)}^{\rm{2}}}}}{{{\rm{twicesomethingelse}}}}[/math]

I put this one in because I know joigus likes taylor - maclaurin series.
It arises in the truncation of such a series for many purposes eg

correction to a measured line on sloping ground

[math]{\rm{correction = }}\frac{{{{\left( {{\rm{heightdifference}}} \right)}^{\rm{2}}}}}{{{\rm{2slopedistance}}}}{\rm{ = }}\frac{{{\rm{\Delta }}{{\rm{H}}^{\rm{2}}}}}{{{\rm{2L}}}}[/math]

Deviation of a circular arc from the straight (tangent)

[math]{\rm{Offset = }}\frac{{{{\left( {{\rm{straightdistance}}} \right)}^{\rm{2}}}}}{{{\rm{2circleradius}}}}{\rm{ = }}\frac{{{\rm{\Delta }}{{\rm{L}}^{\rm{2}}}}}{{{\rm{2R}}}}[/math]

 

Finally there is 'onion differentiation'  - differentiation from the oustside in.

When differentiating a complicated trigonometric expression

"First the power, then the trig, then the angle" is the rule

Edited August 19, 2020 by studiot

[OldChemE]

Color codes for resistors:  Bad Boys rape.......  Totally out of place today and I would not repeat it now-- but it got me through my EE courses 54 years ago.

[joigus]

On 8/19/2020 at 10:32 AM, studiot said:

I learned this one because my first year flatmate mumbled it every day for a year and came top in Chemical Engineering.
He said it was the only thing he learned for the exams and covered eeverything, which is not far from the truth.
It is a general flux formula for momentum, mass energy etc.

I still have some difficulty with this, but maybe it's not 'up my alley' as they say. Every trade has its lingo.

On 8/19/2020 at 10:32 AM, studiot said:

I put this one in because I know joigus likes taylor - maclaurin series.

I do. Brilliant ideas never die. But Fourier rocks too.

14 hours ago, OldChemE said:

Color codes for resistors:  Bad Boys rape.......  Totally out of place today and I would not repeat it now-- but it got me through my EE courses 54 years ago.

There seems to be a branch of mnemonics here ranging from cross-cultural to off colour.

https://en.wikipedia.org/wiki/List_of_electronic_color_code_mnemonics

Some of them I find more difficult to remember than the sequence of codes itself.

On 8/19/2020 at 9:25 AM, Dord said:

[...]

Absence of evidence is not evidence of absence.

ABC - the detectives' mantra

[...]

ABC - radio comms & report writing 

[...]

Thank you. I find especially useful the report-writing one.

[studiot]

1 hour ago, joigus said:

I still have some difficulty with this, but maybe it's not 'up my alley' as they say. Every trade has its lingo.

No its very widespread.

 

It is just a statement of the equation for a control volume

The base is the input.

If you subtract the output, what remians must be left inside the control volume ie is the accumulation.

Think income minus expenditure = addition to bank balance.

[Strange]

1 hour ago, studiot said:

No its very widespread.

 

It is just a statement of the equation for a control volume

The base is the input.

If you subtract the output, what remians must be left inside the control volume ie is the accumulation.

Think income minus expenditure = addition to bank balance.

Yes, I can see that input - output = accumulation would make a bit more sense.

[moth]

17 hours ago, OldChemE said:

Color codes for resistors:  Bad Boys rape.......  Totally out of place today and I would not repeat it now-- but it got me through my EE courses 54 years ago.

Bless Violet's big heart!

Questions to ask, and answers to question ?

[joigus]

On 8/18/2020 at 3:42 PM, dimreepr said:

It doesn't seem to change the need for rigor, while leaving the less rigorous an invite too join in; a dear wish of mine is to play a musical instrument, but I've yet to receive an aphorism that by-passes the need to practice...

I don't think any aphorism will bypass the need to practice. Not even with tensor calculus.

But how about this for pep talk?:

If Django Reinhardt could do it, why can't you?

[michel123456]

11 hours ago, joigus said:

 Django Reinhardt

Are you in Belgium?

------------------------------------

If you want to remember the value of Log 2, look at the face of your colleague next to you: the ear (3) the eye (0) the nose (1) the other eye (0) the ear (3) and you get log 2 = 0,30103 (approx.)

[joigus]

2 hours ago, michel123456 said:

Are you in Belgium?

No. I learnt about Django Reinhardt from within my light cone, by gathering signals.

Very nice mnemonics. +1

The left ear is inverted.

2 hours ago, michel123456 said:

Are you in Belgium?

I mentioned Django Reinhardt because he had two fingers burnt, and managed to play beautifully with only eight fingers.

Edited August 21, 2020 by joigus
Addition

[dimreepr]

13 hours ago, joigus said:

If Django Reinhardt could do it, why can't you?

Because I'm lazy and content with that, which makes my speciality 'being efficient, in doing enough to live and have time left over to think and dream'. 😊

And for the life of me, I can't make an acronym from that.

 

[Ghideon]

On 8/18/2020 at 1:43 PM, joigus said:

So my suggestion is: Let's all share those brief phrasings that have helped us remember an idea,

Nice topic! My personal motto regarding science in relation to engineering and personal interest

In mainstream science I depend
Its correctness and methods I defend
while hoping for flaws until the end

As an engineer I trust and depend on well established theories to be correct and to have predictive power within their limits. I have limited possibilities and interest to confirm their correctness, I’m depending on them to be correct. I have, in my profession, not yet observed an issue that could not be explained by correct application of mainstream physics.

I try to defend the established mainstream when required but also the methods that finds issues and drives updates; theories should be modified when there is support by observations or new evidence. 

That said, I always hope for flaws to emerge. I do not expect or have hopes to be the one that discover such flaws. I don not think it is likely for something new to replace for instance General Relativity but that does not prevent me from having a (how ever small) hope that something new and even better will be established. Yet another confirming observation of GR is exciting. But genuine evidence* of something macroscopic that contradicts and requires modification or replacement of GR would be even more exciting.

 

*) Not counting known limitations such as Black Hole centers, Quantum effects etc.

Edited August 21, 2020 by Ghideon

[Strange]

If we are getting poetic:

"A little learning is a dang'rous thing;

Drink deep, or taste not the Pierian spring:

There shallow draughts intoxicate the brain,

And drinking largely sobers us again.