Anything Smaller Than Quarks and Leptons?

[Sensei]

You don't have to blindly believe what scientists say, but there should be some element of trust here. Not that I am sure it is relevant to the discussion here.

 

If some scientists is publishing his/her discovery, other people (not just scientists) can check it and verify and confirm or contradict (perhaps showing where has been made mistakes).

Trust is necessary only if somebody doesn't want to learn.

 

If I say you 1 m^3 volume of water has mass 1 ton. You Nicholas, can believe me on word, or check it by yourself. Tell me how you would do such experiment.. ?

[Nicholas Kang]

Sensei, you mean I shouldn`t simply trust one`s statement?

[Sensei]

Sensei, you mean I shouldn`t simply trust one`s statement?

 

That was quote on top of some Renaissance school if I recall correctly.

Don't trust anybody words. Verify them all by yourself.

Edited June 10, 2014 by Sensei

[Nicholas Kang]

You are right, Sensei.

1m cubed of water contains 100cm times 100cm times 100cm of water, which equals

1000000cm cubed

 

we know pure water has density 1g/cm cubed

1 metric tonne is 1000kg, which equals to 1000 times 1000gram, which equals

1000000g

 

So,

1000000/1000000

you get 1g/cm cubed or simply 1, which verifying the statement 1m cubed of water has mass 1 tonne.

I verify the above statement by maths theoretically. Now, for practical experiment, you can simply use giant containers to store 1m cubed of water and simply weight it by all means(any possible method), like using gigantic weighting machine, or maybe other sophisticated apparatus if possible.

 

if you must do it in a science lab, then you can only use proportion method, which means instead of 1m cubed to 1 tonne, you can simplify the values to maybe 100cm cubed to 100gram and test it. Again, this idea requires theoretical skills to simplify the exact value before doing such experiment because it is very unlikely to carry out experiment involving 1m cubed of water and 1 tonne in a science lab.

[ajb]

Don't trust anybody words. Verify them all by yourself.

But this is not always going to be possible.

 

For example, if Nicholas Kang now asks some question about string theory, let us say why 11d for a concrete example, I can explain to him why in general terms, but I would not expect him to go through the calculations again himself (you can find calculations in many string theory textbooks). So, many people have verified why 11d using related but slightly different arguments and so everyone is happy with this. But again, Nicholas Kang may not yet be in a position to understand the steps of the calculations, he cannot verify this for himself.

 

Another example could be any experiment that Nicholas Kang cannot reproduce. Moreover, he may not really be in a position to deeply analyze the paper and all the statistics and so on.

 

There has to be some element of good will and trust between what scientists say and how the general public understand science. Now, that is not to be confused with me saying that scientists are always right or that expert opinions don't change. With new evidence old established ideas can change and will change.

[Sensei]

we know pure water has density 1g/cm cubed

 

But first you need to verify that water has 1 g/cm^3

Take f.e. glassware with volume scale, put it on Weighing scale, reset settings, fill with water, read volume and mass. Calculate density of substance in g/cm^3.

 

Some scientists did it with the all chemical elements, the all chemical substances ever produced.

It was repeated over and over again during the last couple hundred years with better scales to receive more precise results.

 

or maybe other sophisticated apparatus if possible.

 

You can take a bit of substance, let's say 100 grams, measure it's volume, and then extrapolate to higher mass, higher volume.

 

That's how you can calculate mass of Earth. Average density of Earth multiplied by volume = mass. Volume of Earth = 4/3*PI*radius of Earth^3

Edited June 10, 2014 by Sensei

[Nicholas Kang]

More precise result? I don`t think so. The same as things smaller than string. Even you magnify until the string level of the beaker`s calibration, smaller than atoms and quarks of the beaker`s wall, you can`t get the most precise result because string do occupy space. So, infinite answer, impossible to get the final answer. Measurement can infinitely accurate, until no end. Your decimal point will reach till no end, filling up the entire universe and beyond, but still can`t figure out when the decimal points stop.

[Strange]

How can it be possible to stop curiosity? It is hard to believe that at a point, anything is fundamental. You mean, people must believe in what scientist say and then no notion would emerge?

I don't think anyone is saying that.

 

As ajb says, there needs to be an element of trust, though. Understanding why scientists believe the things they do, helps. In other words, understanding the basics of science, the evidence supporting current theories and, perhaps, the history that led to the currently accepted models can all help.

 

Also, if you study science at university, you get to repeat a lot of the basic experiments (and your own variations on them) and see that they do produce the results you have been told. At some point, you have to extrapolate from knowing that these experiments work to accepting that the LHC (for example) actually does what is claimed.

 

Do tell me other alternative theories apart from the string theory. Thanks.

I will mention Sundance Osland Bilson-Thompson's work (if for no other reason than it is such a great name)

http://en.wikipedia.org/wiki/Sundance_Bilson-Thompson

[Nicholas Kang]

Sometimes, you can trust scientist and you must trust scientist. If you don`t trust scientist, then your mind would be empty, not broaden with knowledge. But, when your knowledge reach a point in which you think you should revolutionize, you should go for that. It depends on the context. Since you have wide knowledge, it is time for you to think, think, think and think. Reconsidering basic principles, are they true? How would you falsify them if you think they are false? Think of Newton and his classical physics laws? Everyone did think and learn during secondary school. But who rethink it and combine his idea with Maxwell`s Equation? Einstein. Only Einstein? No, others did so. But they are not as farsighted as Einstein. So, I should emphasize the fact that you should trust scientists before you are dare enough to challenge them and firm enough to challenge them. Only until you reach a point in which you are ready and steady, it is time to unleash your powerful mindset. If you success, you can simply throw the ordinary theory into the rubbish bin. People would just follow your theory until it is being challenged again.

[Sensei]

For example, if Nicholas Kang now asks some question about string theory, let us say why 11d for a concrete example, I can explain to him why in general terms, but I would not expect him to go through the calculations again himself (you can find calculations in many string theory textbooks). So, many people have verified why 11d using related but slightly different arguments and so everyone is happy with this. But again, Nicholas Kang may not yet be in a position to understand the steps of the calculations, he cannot verify this for himself.

 

I remember other thread on SFN where person interested in string theory asked what are all these 11 dimensions. And nobody, literally nobody, could answer...

I don't think so he asked for precise math. Just simple explanation.

[Nicholas Kang]

Sensei, I am just 15 years old and it is not wrong if I don`t understand string theory. Actually, I did come across books about string theory. I just know briefly about it. 11 dimension consists of 4 dimension spacetime and the other 6 dimensions came from some functions in Maths. All forces and matter particles fit well in 11 dimension, thus it must be 11 dimension, mustn`t it? Am I right, Sensei?

[ajb]

I remember other thread on SFN where person interested in string theory asked what are all these 11 dimensions. And nobody, literally nobody, could answer...

 

I don't think so he asked for precise math. Just simple explanation.

My example is just a random example to make the point that not everyone (including myself) can verify everything.

All forces and matter particles fit well in 11 dimension, thus it must be 11 dimension, mustn`t it?

It is to do with the fact that (free) super strings can only be consistently quantised in 11d. Other dimensions have what we call anomalies, which really the statement that some of the classical symmetries of the theory do not survive quantisation process. In particular if the local symmetries do not survive the quantisation process then the theory is not well-defined.

[Nicholas Kang]

String theory sounds complex and what is quantisation process? What is local symmetry and classical symmetry?

[ajb]

String theory sounds complex and what is quantisation process? What is local symmetry and classical symmetry?

I won't be able to explain this properly to you here.

 

Try wikipedia first and then get back to us with proper questions if you have any.

[Nicholas Kang]

It is really a crazy job for a 15-year-old to understand and study string theory. If I could do that, I would have break the world record. Anyway, I will try. Thanks for promoting enthusiasm for me to study string theory.

[ajb]

It is really a crazy job for a 15-year-old to understand and study string theory.

Details for sure, but the general idea you could cope with.

 

Loosely we study the classical and quantum theory of 1-d extended objects rather than 0-d point-like objects. The rules of passing from a classical to a quantum theory only work for (super)strings in 11d.

[Sensei]

It is really a crazy job for a 15-year-old to understand and study string theory. If I could do that, I would have break the world record. Anyway, I will try. Thanks for promoting enthusiasm for me to study string theory.

 

You should concentrate on classical physics. When it will have no mysteries to you, learn Standard Model.

Then you can go to unconfirmed theories. Without extensive knowledge you can't even judge if something is correct or incorrect. Plausible or not.

 

Otherwise you're in kinda like position of somebody who is reading about calculus without knowing what is multiplication..

Edited June 10, 2014 by Sensei

[Strange]

Sensei, I am just 15 years old ...

 

I had not realised that. I think you are doing very well. But, while it is great to have imagination and ideas, always rememebr that the first step for a scientist (or an engineer) is to test the idea. This can be as simple as a quick calculation to make sure it is in the right ballpark, or maybe a search for evidence that contradicts it (*) or, as you have done, discussing it on a forum like this.

 

(*) Note: you can usually spot the "crank" theories because they will only look for evidence that confirms their idea. A good scientist (or engineer) will start out looking for things that will break their idea.

[Nicholas Kang]

Strange, you are really strange. You can see my details in my profile. One question, why secondary school don`t teach modern physics but only classical physics. Since you know most of Newton`s Law had been overturned by Einstein`s theory, why the school still teach us the inaccurate thing, making us maybe or somehow face problem when entering university.

Edited June 10, 2014 by Nicholas Kang

[ajb]

Since you know most of Newton`s Law had been overturned by Einstein`s theory, why the school still teach us the wrong thing, making us maybe or somehow face problem when entering university.

It is not the wrong thing. Newtonian physics applies very well to a great deal of natural phenomena, as long as the bodies are not too small, too heavy or moving too fast.

 

In physics we are worried about how well a theory matches the observations. If it matches well within experimental accuracy and within the theory's expected domain of validity then the theory is good. It if does not match well then it is a bad theory. The wording maybe subtle, but it us not correct to call Newtonian physics wrong.

Edited June 10, 2014 by ajb

[Nicholas Kang]

Not "wrong", then sorry for inappropriate usage of words. Then, I will change my word to inaccurate theory.

Edited June 10, 2014 by Nicholas Kang

[Strange]

Strange, you are really strange. You can see my details in my profile.

I never looked (Nor at your signature.)

 

One question, why secondary school don`t teach modern physics but only classical physics. Since you know most of Newton`s Law had been overturned by Einstein`s theory, why the school still teach us the wrong thing, making us maybe or somehow face problem when entering university.

 

We start out learning the simpler models that are "good enough". If you want to solve the sort of problems you will encounter in real life, then Newton is good enough. Expecting people to do several years of advanced (post graduate) math before they can calculate how fast a stone will fall is probably unrealistic.

 

The same is true in all subjects. At school you learn that certain chemicals combine in certain ways. At university, you start to learn about how this explained by quantum theory and electron orbitals.

 

This is sometimes known as "lying to children" but I think that is unfair; it is essential to start out with the simple models.

[ajb]

Not wrong, then sorry for inappropriate usage of words. Then, I will change my word to inaccurate theory.

But Newtonian physics can be very accurate, that was in part my point.

 

Outside of the domain of validity of Newtonian physics it is not very accurate, okay, but calling Newtonian physics inaccurate is not a good choice of words either, not without some quantifiers anyway.

[Nicholas Kang]

Ok, thanks. But you know I am really attracted by the interesting topics in the university. I am eager to study at university now.

Not "wrong", not "inaccurate"? Could you please tell me the appropriate word that should be used?

[ajb]

Not "wrong", not "inaccurate"? Could you please tell me the appropriate word that should be used?

I am not sure there is a word here, at least not one that is not technical like "effective".

 

Anyway, I hope you see my point.