[Review] VCE Physics 3/4

[lzxnl]

Are you kidding? It has the reverse effect on me. I hate doing VCE physics homework. I really do. Even though spesh is just as simple for me, it's at least mentally stimulating and interesting to do. Physics is just poorly designed and a mental anaesthetic for me. I mean 100 Checkpoints question on the photoelectric effect and wave nature of matter...when really I could group all of them into around ten question types or so.

[Twanny666]

I'm doing VCE Physics this year and I agreed with most of what you have to say....
I can't stand learning from the Heineman Text book.
In 1/2 I really struggled but I guess I didn't work at all haha..
My classes aren't really productive and I find that I learn a lot in class that is unrelated to what will be on my VCE Exam at the end of the year.
Most of our Sac's are completely dissimilar to some of the Practice Exams I have done.
I feel like I'm wasting a lot of my time... but the subject isn't relatively hard, especially when I just write most of the theory out from a cheat sheet.

[P0ppinfr3sh]

Are you kidding? It has the reverse effect on me. I hate doing VCE physics homework. I really do. Even though spesh is just as simple for me, it's at least mentally stimulating and interesting to do. Physics is just poorly designed and a mental anaesthetic for me. I mean 100 Checkpoints question on the photoelectric effect and wave nature of matter...when really I could group all of them into around ten question types or so.

I agree. I've found that physics is just essentially subbing values into an equation and as you said, there's an extremely limited amount of question types for each topic (at least this is what i've found in my experience) and it does eventually get boring and tiresome, (while on the other hand i reckon i could do spesh questions for hours).

P.S. Personally i thought interactions of light and matter was the most area of study, (although we didn't go into the depth that i would've liked).

[lzxnl]

Light and matter...part of it was a lie...electrons don't form standing waves around atoms -.- there are electron-electron repulsions too.

[Aurelian]

Light and matter...part of it was a lie...electrons don't form standing waves around atoms -.- there are electron-electron repulsions too.

Sure, contemporary quantum mechanics doesn't view electronic structure in this simple way anymore, but the model in the VCE course was once taken very seriously by scientists. If you're going to consider this part of the course a "lie" because it concerns a model for something we now have better models for, then you're going to have to call all of the stuff on classical mechanics a "lie" as well.

As an aside, it's also not entirely true that electrons don't form standing waves. While we don't model them as simple one-dimensional waves anymore, the wavefunctions we do use to describe atomic orbitals aren't called wavefunctions for no reason...!

[lzxnl]

Electrons certainly don't form standing waves in the way that VCE physics suggests they do; not fitting sine curves to a circle at least. The implicit assumption is that this is how all atoms operate as well; at least, I've seen questions that make general statements about fitting wavelengths around an atom applying to all atoms. If it's just those companies, then ok.

You're right, the wavefunction does suggest that the electrons form some form of wave structure which is stable with itself, but these wave functions aren't simple sine curves that we can stretch and squeeze to form different energy levels.

As for your point on classical mechanics, classical mechanics generally works very well to a high degree of precision for a lot of everyday scenarios; it's a very good approximation. The Bohr model works for one specific instance where the nucleus is surrounded by one electron, and fails miserably elsewhere. I don't quite see how we can make an analogy here.

[Aurelian]

Electrons certainly don't form standing waves in the way that VCE physics suggests they do; not fitting sine curves to a circle at least. The implicit assumption is that this is how all atoms operate as well; at least, I've seen questions that make general statements about fitting wavelengths around an atom applying to all atoms. If it's just those companies, then ok.

Yes, I think it's fair to say that the model is treated too matter-of-factly and as objective "truth", but that's certainly not to say there's anything wrong with teaching it. Provided that the appropriate historical context is given, it's a very important first step for anyone learning about quantum mechanics. Would you rather have students be confronted with a partial differential equation in three dimensions at the outset of their very first lesson in quantum mechanics...?

You're right, the wavefunction does suggest that the electrons form some form of wave structure which is stable with itself, but these wave functions aren't simple sine curves that we can stretch and squeeze to form different energy levels.

Never said it was, but, again, the idea - provided that it is treated in an appropriate fashion - is really the only way you're going to gently ease students of physics into the idea of quantization which emerges out of wave mechanics. Once again, so long as it's made clear that this was an early model of energy quantization in atoms, and that it is now outdated, I don't see any problem with it being taught (in fact, I definitely think it *should* be taught). Triply again, I agree that this probably isn't made clear by the vast majority of physics teachers and textbooks, which is unfortunate.

As for your point on classical mechanics, classical mechanics generally works very well to a high degree of precision for a lot of everyday scenarios; it's a very good approximation. The Bohr model works for one specific instance where the nucleus is surrounded by one electron, and fails miserably elsewhere. I don't quite see how we can make an analogy here.

The point was a logical one, and it still stands; if you consider the crude model of electrons as one-dimensional standing waves as "false" because it is outdated and because there are more accurate alternative models available, then for the same reasons you are committed to regarding Newtonian mechanics as false too.

However, the more fundamental point here is that people shouldn't be assessing any scientific models as either "truth" or "lie" at all, and doing so reveals a misunderstanding of scientific method.

Anyway, take home point is just this: models can be outdated, but that doesn't make them unimportant, especially where scientific education is concerned.

[lzxnl]

I am perfectly fine with scientific models, even if they're outdated (even special relativity is technically outdated) but my understanding of the VCE physics course doesn't mention the problem with the Bohr atom in not taking into account electron repulsions. I've had questions that ask me to explain quantisation of electron energies by fitting integer numbers of wavelengths around an atom, and that's really what annoys me.

The point was a logical one, and it still stands; if you consider the crude model of electrons as one-dimensional standing waves as "false" because it is outdated and because there are more accurate alternative models available, then for the same reasons you are committed to regarding Newtonian mechanics as false too.

However, the more fundamental point here is that people shouldn't be assessing any scientific models as either "truth" or "lie" at all, and doing so reveals a misunderstanding of scientific method.

Anyway, take home point is just this: models can be outdated, but that doesn't make them unimportant, especially where scientific education is concerned.

I only consider it "false" because of the horribly narrow set of instances where it can be applied. It's only accurate for one very specific, unrealistic case, yet the course generalises this to all atoms in general. If Newtonian mechanics only worked for matter with a temperature of over 100000 K, but people were asked questions about Newtonian mechanics at normal temperatures, that would annoy me too. As it is, as Newtonian mechanics works very well for speeds under 3*10^6 m/2, masses less than that of the earth (probably works for larger objects too) and macroscopic objects in general...it suits everyday applications quite well, which happens to be a large part of our lives.

[muscle min]

yeah I have to disagree with you on this one. I did physics last year and asian failed. People do the course thinking that its difficult and expecting to do well, when its really not. But, if you're careless, you could have a really thorough understanding of the course and still not do well. I think its a bit like further in that regard.

[pi]

I see your point, but 43 is not an "Asian fail"

[muscle min]

I see your point, but 43 is not an "Asian fail"

you're right. its more than a fail. its nothing short of total dishonour.

[pi]

Yes you can repeat subjects with no problems.

Now let's get back on the topic of bagging VCE Physics

[muscle min]

Wtf you're allowed to retake subjects?

Do you get marked down or anything?

some schools let you. I used to go to Macrob, but they don't let you repeat a subject unless you really fail it. But my current school lets me repeat so yolo.

You don't get penalised for repeating.

[BasicAcid]

some schools let you. I used to go to Macrob, but they don't let you repeat a subject unless you really fail it. But my current school lets me repeat so .

You don't get penalised for repeating.

Oh I never knew that, cheers mate! And as if you weren't satisfied with 43, I'll be stoked with 43 this year haha

[lzxnl]

There is someone who repeated Methods after getting a 43 one year. They didn't go to classes at all, but did the SACs and got a 50 the next year.