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TOK 2022 12 concepts

Friday 2 April 2021

You may not have noticed but TOK has changed. The main differences are the introduction of 12 concepts and the exhibition. As far as we physics teachers are concerned our role is pretty much the same as before. To point out interesting ways that knowledge is acquired, used and developed in physics, all those TOK moments are still TOK moments so we won't be rewriting all the TOK sections on the website, thank goodness for that. So, what about these 12 concepts?

  • evidence
  • certainty
  • truth
  • interpretation
  • power
  • justification
  • explanation
  • objectivity
  • perspective
  • culture
  • values
  • responsibility
It might be worthwhile considering how these concepts are used in a physics context so when we have our physics TOK moments we can mention which of these it is related to. I was recently sent a package of material for TOK teachers to help them to associate each of these terms to physics. None of the material was taken from the actual IB physics course in fact none of it was physics. Mostly biology. Are we really so secretive that no one outside our departments know anything about what we teach? I think there is masses of TOK material in our subject guide, it's just a matter of spreading the word. I'll have a quick go with the 12 concepts.
Evidence
That's an easy one. Everything we do is based on evidence which comes from observation and experimentation. Brownian motion is evidence of the particle nature of matter. This is good evidence because it is difficult to explain in any other way. Line spectra provide evidence that atomic electrons exist in energy levels. There's plenty more where this came from.
When students evaluate the weaknesses in their IA we ask that they provide evidence that the weaknesses actually caused a problem. Did the scatter of points on their graph reflect the random errors that would be present due to the inexact positioning of the ball?
Certainty
We generally focus on uncertainty but it's the same thing, actually it's the opposite but I think it counts. Why are we so concerned about uncertainty? because if we can't be certain about our results then we can't use them as evidence (2 in 1). In engineering they talk about tolerance, it's important to know your nut will fit your bolt.
Truth

Is Newton's 1st law true? Well we treat it like it is. If it wasn't we couldn't solve problems. Does everyone's clock measure the same time? not really but we assume it to be true and it normally doesn't matter that much. When we study relativity we find that moving clocks tick more slowly so we know the statement is false but we keep on pretending it's true. Can things be true within certain limitations? Can you move a bishop horizontally? Of course you can but not in a game of chess.

Interpretation

We interpret experimental results in order to evaluate if they support our theory. Due to uncertainties there can be several different interpretations but they must be based on evidence and the laws of physics. You can't say a relationship is quadratic if the theory tells you it's a sine function.

Power

I don't think they mean work done per unit time but in the same way that a powerful engine can exert a greater force over a given distance in less time, something/body with more power has more influence. Do some laws in physics have more power than others? Which is the most powerful? You could use mechanics to explain how perpetual motion could be achieved but your explanation would be trumped by the second law.

Justification

Justification of a conclusion should be based on evidence or some mathematical consequence of a postulate that is, I guess justification is a bit like proof. How can we justify the statement that you can't travel faster than the speed of light? It's difficult to justify something you can't do, maybe we just haven't tried hard enough. What you can do is justify the postulates then show that this is a consequence.

Explanation

Our bread and butter, if you can't explain it you don't understand it and if you don't understand it you can't make predictions. I once listened to a student explaining to another how a transformer worked, it was completely wrong but afterwards the receiving student said, "thanks, now I understand it". What exactly did he understand? Can you understand an incorrect explanation? Does it matter as long as your prediction is correct? Students struggling with kinetic theory might say that they understand the stuff about the rubber balls but not the gas. The balls are our way of understanding the gas, understand that and you understand the gas.

Objectivity

I think we are pretty objective in physics, at least we are always talking about objects. If you spent ages working on a theory then you probably want your data to fit, this could affect you objectivity. Maybe a student thinks they have a better chance of a 7 if they get a straight line? Choosing data that fits expectations. Sometimes it's difficult to be Mr Spock.

Perspective

We see everything from our own perspective, this is OK provided we can understand that not everyone will see things the way we do. This is the essence of relativity, how we transform measurements made in my frame of reference to find out what they would be in another. Space-time diagrams are a great tool for doing this.

Culture
Now I'm stuck, I'm afraid it's not something I think about when teaching physics. There are obvious cultural biases in the history of physics but not so apparent in the subject as it is packaged today.
Values
Oooh, these are getting harder. What value does our society place on the advancement of physics? Quite a lot when there's a war to be won, or a quantum computer that will be able to crack encrypted data, maybe not so much when researching some more esoteric topic which is so esoteric I can't give an example. Physics graduates are valued for their skills that can be applied to economics.
Responsibility
That old chestnut, are physicists responsible for all the people who died as a result of nuclear weapons, electricity and plastic? Yes to the first two no to the third, that was the chemists.
I have a plan: I'm going to produce some material to be used by TOK teachers about physics. The idea is to make some practical activities that introduce these concepts from a physics perspective but not necessarily using physics, maybe take some piece of art or music and analyse it as a physicist would. Or introduce Feynman diagrams without saying what they are used for. This could be fun.
You can find my first attempts here:

Non linear
28 Mar 2021

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