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supernova1965
20-04-2011, 05:41 PM
If Quantum Theory/Quantum Mechanics was used to create the Transistor how come we still call it a Theory:question:

http://www.physics.ucla.edu/~ianb/history/ (http://www.physics.ucla.edu/%7Eianb/history/)

CraigS
20-04-2011, 06:10 PM
Hi Warren;

A theory, is an explanation of an observed phenomenon.

The explanation remains an explanation, regardless of whether something has been created from it or not. So the title, 'Theory' stays.

Hope this helps.

Cheers

supernova1965
20-04-2011, 06:14 PM
But if a tangible outcome can come from it don't we have to call it a fact. I mean if it were wrong how could we use it to make something work:confused2:

CraigS
20-04-2011, 06:28 PM
No. A theory is an explanation … ie: it describes 'how' something works.


What if no-one knows, or can ever know, the 'truth' of how something works ?
Ie: there is no-one who knows the actual truth about how something actually works.

How would you ever gauge whether the explanation was 'right' or 'wrong' ?

Science doesn't dabble in the truth of anything. People do … science says nothing about 'truth' of how something works. It provides an explanation which fits the observations and any known facts.

A theory's ultimate job is to make accurate predictions.

Cheers

KenGee
20-04-2011, 06:53 PM
In Science “theory” is a explanation of the observed facts. In the normal world we might say we have a theory where in science it would be describe as a conjecture or hypotheses. While there is no set rule as such a hypotheses moves to the status of a theory once it’s foundation ideas receive broad support.

It gets on my goat when I hear/read people say it’s only a theory.

CraigS
20-04-2011, 07:08 PM
Here ya go .. a bunch of reasonable definitions:

Fact: A basic statement established by experiment or observation. All facts are valid under specific conditions. Some facts may not be valid when re-tested with better instruments.

Law: A logical relationship between two or more things that is based on a variety of facts and hypotheses. It is often a mathematical statement of how two or more quantities relate to each other. A law is a phenomenon that has been observed many times, and no contrary examples found, that it is accepted as a universal phenomenon.

Hypothesis: A tentative statement such as ‘if A happens then B must happen’ that can be tested by direct experiment or observation. A repeatedly verified hypothesis can be expressed as a law or a theory. A disproven hypothesis can sometimes be re-tested and found to be subsequently verified, as measurements improve.

Theory: An explanation for why/how certain laws and facts exist, that can be tested to determine its accuracy. It takes only one negative example to to disprove a theory and you can't examine all examples of a phenomenon throughout all time and space (the problem of induction). Theories are used to make predictions.

Belief: A statement that is not scientifically provable in the same way as facts, laws, hypotheses or theories. Scientifically disproven beliefs can still be held to be true, (unfortunately :) ).

Cheers

Merlin66
20-04-2011, 08:37 PM
Newton was lucky....
The laws of probabilities were on his side.
What the devil are we going to do when just one apple falls upwards????

renormalised
21-04-2011, 12:50 AM
Worry:):P

avandonk
22-04-2011, 10:15 AM
As for the upward moving apple, Carl Popper covered all of this years ago. Unless some phenomena can be shown to be false by experiment then it has no basis in reality.

All of the deluded people that believe in such things as creationism, fairy stories, quack medicine and many more crackpot nutters to numerous to name or label, take great joy in saying that all of Science is 'only a theory'. They will blog about it incessantly on their laptop while sitting in their airliner seat. Or rave about it on their TV show to their followers.

Nearly everything they do has at it's basis sound application of Science.

It is semantics posing as argument.

They are generally to stupid or ignorant or both to even see their own idiocy. Or is it blatant hypocrisy!

Bert

CraigS
22-04-2011, 10:31 AM
The upwardly falling apple would, (theoretically), occur in the presence of matter/anti-matter interaction !

Now this phenomenon can be shown to be false right here on Earth, right now!

So, the repulsive matter/anti-matter force must be real !
:P :)
Cheers

PS: errr …. no .. that's not right … anyone ever seen an anti-matter apple ? … Is an anti-matter apple part of the phenomenon, or part of the theory ?. .. :P :)

avandonk
22-04-2011, 10:45 AM
Newton's apple is another myth. It is a plausible story told in hindsight. It was only related to bring the Gravitation Theory down to Earth for the layman. No pun intended!

All of the antimatter ever created by man in colliders would barely fill a gnats eyelash tip! This includes the countless Positrons generated each year in the worlds bigger Synchrotrons.



Bert

CraigS
22-04-2011, 10:49 AM
I was just playing around on the tail of the Darkness & Antigravity (http://www.iceinspace.com.au/forum/showthread.php?t=74470) thread.

I'm not in a particularly serious mindset today.

Cheers

sjastro
22-04-2011, 01:35 PM
Craig,

The link you provided me for the paper on antigravity can't be taken seriously either.:D

Regards

Steven

CraigS
22-04-2011, 02:08 PM
Ouch !
Brutal !

perhaps true, too .... but why not ?
:)
Cheers

sjastro
22-04-2011, 11:03 PM
The paper is here. (http://arxiv.org/pdf/1103.4937v1)

There are a couple of questionable statements made by the author.

First of all is his example from electrodynamics using the Lorentz force law.
He uses CPT symmetry and finds the Lorentz force for a particle/particle interaction is the same as an antiparticle/antiparticle interaction.
In other words the equation doesn't change sign for each interaction.
The particle/antiparticle interaction changes the sign of the force through the charge conjugation (C) operation due to opposite charges.

This is a valid for the electromagnetic force as it has the unique property of being a repulsive or attractive force. Applying the CPT symmetry to the strong nuclear force doesn’t change the nature of the force. Changing the charge conjugation doesn’t change its direction. This is supported experimentally by Mesons which are composed of quark/antiquark pairs bonded together by the strong force.
The strong force would serve as a better model for gravitational forces as both are forces of attraction. Since the strong force does not change from an attractive to a repulsive force under a CPT transformation, then it is hard to see how this would apply to gravitational forces.

The other issue is the T transformation in the CPT symmetry. The author assumes the Feynman-Stuckelberg interpretation where an antiparticle is simply a particle travelling backwards in time. This defines the T transformation which is a time reversal operator.
The reversal of time when applied to the Universe (through GR) has serious consequences as it violates the second law of thermodynamics.

Regards

Steven

CraigS
23-04-2011, 06:41 AM
Thanks for that Steven.

Looks like the guy who wrote this paper isn't concerned with being bound by earthly observations, which hold the rest of us mortals on the ground.
:)
I also noticed this was his second attempt at writing this paper. The initial one came out around the same time last year, but with less detail.

I guess we can put your points on the growing heap, and show the whole concept the door, eh ?
:)

Cheers