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AbsoluteValue

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Question: Evaluate the effectiveness of the Standard Model of the atom in describing all interactions in matter. (8 Marks)
How do I get 8 marks for this monster question?
If I do the following do I get the marks?
1) Talk about the 4 forces (gravitational, electromagnetic, nuclear (strong) and nuclear (weak)) in details to get 4 marks.
2) Saying that the standard model was able to explain each force and how bosons create each force to get 1 mark.
3) Discuss the limitations of the model i.e. gravitrons have not been discovered yet, and that relativity also describes gravity (the well and bending of space time fabric theory) so the standard model isn't able to explain gravity, also gravity is extremely weak compared to other forces which is not explained too) to get 2 marks.
4) Neutral evaluation to get 1 mark.
So what should I do for a monster 8 mark question like this, if I say the stuff above do I get 8 marks ???
 

AbsoluteValue

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Also, can anyone explain to me how the strong force works?
This is what I know:
The strong force is the force that acts between quarks to bind hadrons together. Strong Theory suggests that the force is effected through the exchange of gluons, which are predicted to be massless, just like photons. But this theory doesn't explain how meson transfer or gluon exchange overcomes the repulsive electrostatic force between neighbouring quarks (protons inside the nucleus).
Quantum Chromodynamics suggests that gluons are exchanged in such a way to make quarks with unlike colours attract. As stated before, gluons are exchanged between particles bounded in aHadron, such that the net colour charge is zero. This can be achieved when a red, blue and green quark are combined (Baryon) or when a quark and anti quark of the same colour are combined (Meson) (Note: colours refer to charge).
Is my understanding of the strong force correct or do I need a better understanding? Also, what is the weak force, I honestly have no idea what that is.
 

HiRe education

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Hi,

You probably won't be getting 4 marks for simply describing the fundamental forces. That will probably get you 1 mark.
Your answer is missing the KEY FUNDAMENTAL focus of the standard model for the HSC course which is the explanation of:

(i) Quarks
(ii) Leptons
(iii) Bosons (though you have mentioned this)

Draw up a table which identifies the 12 fundamental matter particles [fermions] (6 quarks - up, down, charm, strange, top, bottom and the 6 leptons - electron, muon, tau, electron neutrino, muon neutrino and tau neutrino) and their charges.

Outline how quarks can never exist on their own but rather in composite particles called hadrons. qqq = baryon q(anti-q) = meson. (Give examples)

You might also want to talk about anti-matter and of course, the infamous HIGGS BOSON which was purportedly discovered just this year on 4 July.

And yup. Make an evaluation. Probably somewhere along the lines of it is highly successful in explaining the existence of matter and it's interactions with the weak, strong and electromagnetic force but fails to incorporate the gravitational force.



As with the strong force, all you need to know of it for the HSC course is that it is necessary in order to overcome the electrostatic force between protons in the nucleus and hence, keep the nucleons together in a stable nucleus. As well as this, you will need to know that:

o It is the strongest of all the fundamental forces .

o It is repulsive at extremely short distances (~ 0.5 x 10-5 m) and then becomes attractive with rapidly decreasing strength as distance increases.

o It is independent of charge and mass .

o Its range is extremely short. At distances greater than about 2 x 10-15 m, the nuclear force is effectively zero.


In regards to the weak force, simply knowing of its existence if sufficient for the HSC course. You DO NOT need to know what it does, what it is nor how it works.

Hope this helped :)
 

MaccaFacta

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I am a bit puzzled by the original question. "Standard Model of the atom" is not a phrase you will find in the HSC syllabus. The Standard Model mostly relates to the tiniest things that science can measure - electrons, quarks, etc which are smaller than atoms. So the "Standard Model of the atom" is a bit like saying the "Gravitational theory of the Moon". There is a lot more to gravity than the rotation of the moon around the earth. My advice would be to stick to the syllabus and past HSC papers when working on this topic. Some textbooks push their own little agenda on some topics - including stuff that hasn't and never will be included in a HSC exam.

Regarding the strong force - it is the strongest of all of the fundamental forces. It operates over very short distances. It is what holds the protons together in the nucleus (electrostatic repulsions are enormous). It is very easy to go a long way past what the syllabus requires in relation to this stuff so, again, stick to the past HSC papers and the syllabus itself when trying to figure out what to study. The weak nuclear force is involved in beta decay and in other types of radioactivity. Again, don't try to go beyond the syllabus. There is nothing in the syllabus about W and Z particles, the Higgs Boson or quantum chromodynamics.
 

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