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Was the SL paper 2 too difficult?

Tuesday 13 July 2021

There has been a lot of discussion on the IB physics teachers group about the difficulty of the physics exam in particular the SL exam, this has been provoked by the low grade boundaries in the 2 papers.

Paper 1

7 - 60%

6 - 53%

5 - 47%

4 - 40%

3 - 23%

2 - 20%

1 - 17%

Paper 2

7 - 60%

6 - 44%

5 - 26%

4 - 14%

3 - 8%

2 - 6%

1 - 4%

Remember the grades are supposed to be defined by the following table (this might be out of date, I haven't checked for a new version, but the principle is the same).

Can you really claim that a student gaining 14% in paper 2 has a reasonable knowledge and adequate understanding of the subject? I don't think so, a reasonable knowledge should be more like 40%. This exam was too difficult which means it was not suitable for testing students at this level. If we took the extreme case that nobody could answer any of the questions then either everyone would get 1 or 7, there would be no differentiation. In sport climbing route setters have the same problem, if its too easy everyone gets to the top, if too difficult no one gets off the ground. The competition would have to be run again and I guess the IB would go by the predicted grades. The situation here isn't so extreme but there would be a point when they would have to say the exam was null and void. The situation is quite extreme though, I wonder how much they relied on predicteds to get the final grade. There must have been some correlation otherwise there would be about 2 grades difference between students in schools doing the exam and schools taking the non exam route. I thought I might analyse the exam to see what is going wrong.

Paper 2 is supposed to be 50% Objective 1&2 50% objective 3, these objectives are related to the command terms.(this is a shortened list).

Let's see how the paper stands up. I'm afraid I can't post the paper here, if you want a copy email me or leave a comment.

So, there are too many obj 1 and 2 questions, it should have been too easy! But look at the number of obj. 1 questions, only 12%. Let's take a closer look.

  • 4c is drawing arrows on an N vs Z graph, this is not easy, I think its more of a "plot" than a "draw" and that's obj. 2.
  • 5bii is draw the position of nodes from the information given. I think this is deduce obj. 3.
  • 6d State 2 reasons why future energy demands will increasingly be reliant on sources such as photovoltaic cells. The IB definition of state is: " Give a specific name, value or other brief answer without explanation or calculation ." This is not a state question. Outline may be more appropriate. " Give a brief account or summary " obj. 2
  • 4a Write down the A and Z numbers (6 in total) for an electron capture reaction. This isn't even on the syllabus, it's a deduce and calculate question.

So there we have it, no easy marks in the whole paper!

In extreme cases I advise students who have very little understanding of the concepts to simply memorise all definitions and laws so they can at pick up some easy marks. That advice would have got them zilch. The difference between a 1 and a 2 can cost a student their diploma.

Comments 5

Yang Bing 26 July 2021 - 12:08

Hi Chris, is this the official grade boundaries?I haven't found the subject report from IB websites.

Chris Hamper 26 July 2021 - 14:29

I worked them out from the component grades.

denis kuszynski 1 September 2021 - 20:11

Surely this sophisticated analysis explained above only works if EVERYONE writes the exam? My school wrote the exam - in the minority globally as you know. 25% of my students did not write due to COVID illness and their final algorithmically determined results were superior (ok blame my predictions but not the whole story. Psychological pressures of repeated exams on/off stresses also contributed imo) Also my IA's were marked by different examiners. Some were raised by 3, some reduced, and others stayed the same. I briefly explained on each IA the extraordinary circumstances in which students carried out their IA's in the lab and this was accepted by some examiners but not others) This year's results were far from best by a large margin.

Chris Hamper 2 September 2021 - 05:43

Hi Denis; Yes, a bit of a mess. The point you mention about different examiners marking IA's is a good one, it adds another layer on uncertainty to something with large random errors already.

denis kuszynski 2 September 2021 - 13:19

Hi Chris, I guess the 2022 exam marking protocols is an unknown quantity atm. eg IA sample or marking? Additionally, the exam of 2022 class has accumulated greater learning turmoil than any previous group so far so wonder if at all this will be taken into consideration. On your initial question, I found both HL and SL Paper 2's challenging, overly in some parts, and I guess IB were attempting to maintain a semblance of rigour but not sure if this was the right time in the current circumstances. Hoping to make more use of your excellent resources this year but there is just so much quantity, as opposed to quality, out there which students access outside school time. Students here are suffering from a modicum of resource fatigue. Wondering if there is an inverse relationship in there somewhere. Cheers

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