Friday, February 12, 2010

Physics GCSE question

Patrick posts the following on his blog:

Patrick's comment on this is exasperated rather than detailed - he has to teach this stuff. But what strikes me is that all four statements are true of all four appliances. That they all produce heat is obvious. Sound is a form of kinetic energy and they all produce sound (even the toaster and lamp). Because they all produce heat, they all produce light, even if it is just infra red in some cases. In addition, the radio has an oscillator inside it, producing radio frequencies (for tuning) - it's the oscillators in TV sets that the old TV detector vans listened out for - and radio is a form of light. Or heat. And vice versa.

I don't think anything I've just said relies on a knowledge of physics beyond GCSE level. The demarcation of heat and light and radio waves as separate types of energy is out of date by more than a century.

I know this is the first question, and is intended to put the child at ease, but it should be possible to do that and still stay within the realm of contemporary knowledge.


Brian, follower of Deornoth said...

The best bit is the drawings, presumably for people who don't know what a toaster or a radio is.

Anonymous said...

Good grief. Never get a CSE(oops degree) these days. Help

Nigel Sedgwick said...

I have great confidence that there are some bad questions in GCSE science papers, probably on a regular basis. However, I think your complaint here is somewhat off target.

The question calls for answers about "useful" energy transformation. If, as I think is very reasonable in the circumstances, one interprets "useful" as meaning the primary function or the product, I think all but one of your objections go away.

Concerning sound being kinetic energy, I think you are stretching things there too. Sound (in gas) is a longitudinal vibration, which involves a continual exchange between kinetic energy (of unseen gas molecules) and potential energy (of a pressure difference). Bearing in mind that this is a GCSE question and not a degree-level question in physics, I think the fact (in addition to the argument in my paragraph above) that sound is not pretty much 100% kinetic energy of the obvious sort does reliably inform the expected (correct) answer.

Keep looking; I'm sure there are some real howlers out there.

Best regards

dearieme said...

It's disgraceful that there is not a properly testing course and exam for the clever kids. Except at the private schools, who are many of them giving up this rubbish and swapping to other exams. Really we should abolish the state system - it flourished briefly from the Butler Education Act of 1944 to about 1970, and since then it's been downhill all the way.

Nigel Sedgwick said...

I have to support Dearieme here. The problem with those questions is not that the answers are wrong but that the questions are too trivial for purpose.

I took GCE O-levels back in 1968 and 1969, and A-levels two years later. They were much more testing and appropriate for measuring the ability of at least the top third of school pupils. At the same time, there were CSE exams for most others. Some enlightened schools, so I understand, allowed pupils to take a mix of GCE O-level and CSE exams.

The trouble we now have is due to a policy that all must have prizes, and worse, the view that all must have first prizes. Thus the prizes become useless in fulfilling their main function: to assess pupils according to (mostly) intellectual ability and hence suitability for particular types of employment and of further education.

However, I do believe there was an unfairness in the old system, of GCE and CSE exams and of grammar schools and secondary modern schools. The unfairness was not the existence of assessment, in which some are judged less able than others; it was in the coarseness of the assessment. If one failed to make it to grammar school, or one took only CSEs rather than only GCEs, one was definitely disadvantaged, and often unfairly.

The introduction of GCSEs was an attempt to overcome this, by claiming to judge pupils on a single scale. However, this was spoiled firstly by hidden nature of the higher/lower tier exams and subsequently by the further dumbing down so that the ranges for particular grades were altered so that so many get A grades that the distinctions appropriate for fully one third of pupils are no longer made.

What we actually need, to avoid believing we can unify everything onto a single scale with comprehensive schools and a (supposedly) single exam type, is to move forward to a scheme of multiple school types and multiple exam types, that provide useful education for all and useful assessment of ability for all. This latter point must allow for different grades at around 5-percentile points (or even finer at the top) in the total range of ability, through different types of exam and through a sufficiency of grades.

Concerning schools, I note that the Netherlands has 3 overall classifications of secondary school. This is much better than the old UK system of really only 2 classifications. However, I also believe that it would be even better is all or most schools were run independently and set their own entry requirements, which would have a substantial degree of overlap with each other.

Concerning exams, I think the GCSEs should be replaced by (at least) 3 types of exams: those for the middle ground, those for the top ground and those for the bottom ground. Also, it should be an expectation that (nearly) every school would offer at least two of those sorts of exams at the age 16 point.

With such an approach, in which pupils are not tagged (success or failure) in a binary way at any stage, we would surely allow all pupils a much better chance to show their strengths, while also allowing employers and tertiary educational establishments to better judge the suitability of all their applicants.

I hope this helps.

Best regards

Weekend Yachtsman said...

Nigel - all very well, but a (necessariy subjective) judgment of what constitutes "useful" energy is not physics.

It's opinion, possibly politics.

When I compare this sort of thing with my Oxford Local "O" Level physics paper - which I still have - from 1967 (also taken at age 14) it's not hard to see why employers these days have to teach people to read, write, and add up.