Rugby 2013

Curriculum Development in Physics: Then and Now
what has changed – and what hasn’t

Jon Ogborn Institute of Education, University of London

Jon Ogborn, who with Paul Black led the Nuffield Advanced Physics Project, reminisced about those early days of curriculum development and about some of the unexpected ways in which things happened. He then turned to the very different conditions today, reflecting on what we have learned, on what has changed and what the challenges now are for the future.

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As a physics teacher myself it makes me very cross when people say that A level physics is easier now that it was years ago. Professor Ogborn’s talk does show that in the past students could learn things by rote without understanding anything they were learning (this was the system I went through). This is most definitely not the case now.

In the A level physics syllabuses around in 1970 this was the list of topics studied:

– Mechanics

– Heat

– Light

– Sound

– Electricity and magnetism

– Properties of matter

“Standard” theory and experiments were devised in 1920s and 30s and adapted to important 19th century types of measurement:

– Metre bridge and potentiometer

– Copper calorimeters; “Rugby” heavy calorimeter

– Searle’s bar and Lees’ discs

– Ostwald Viscometer

Issues

• Schools were resource-poor

• Getting hold of new apparatus was a big selling point for innovation in the Nuffield A level syllabus and the first big decision (schools had to consider the cost)!

• “Modern physics” meant a bit of radioactivity and photo-electric effect if you were lucky

• Most curricula were organised by a 19th century view of the subject (reflecting JJ Thomson’s view that everything had been discovered by then)

Exams

As mentioned in my introduction exams were rather stereotyped and questions had a very predictable form:

– Define…

– Describe an experiment to…

– Derive a theoretical result…

– Solve a problem… (Geoff Foxcroft and viscosity)

New overall structure of the Nuffield syllabus

• Major schemes:

– Waves

– Fields

– Particles

• End-points:

– Electromagnetic waves

– Second law of thermodynamics (statistical)

– Quantum theory of H atom

• Plus some technology:

– Electronics

– Materials

New exams, designed by the Nuffield team

• Variety

– Coded answer (multiple choice)

– Short answer

– Comprehension

– Long answer (“war memorial”)

– Practical problems

– Investigation

The war memorial question was about which materials would be suitable for a war memorial.

The exam should

• Reflect the course

• Be rewarding to do

• First have validity

• Reliability caming second

The Nuffield group told the Boards what to do!

Boards collaborated (Inter-Board exam)

Freedom and optimism

• “Do what was thought to be right”

• Change seemed good to many (not to all – one teacher: “I suffered learning physics and so should my students”)

• Building a coherent course, not a syllabus (alias “specification”). In the beginning there wasn’t one!

• Free to try “impossible things” [e-m waves, quantum physics, entropy]

Investigations (pioneered by Nuffield)

• First teacher-assessed exam coursework

• Choice and responsibility for students

• Important but not too important as it was only worth 10% of the course

Project work is perhaps the single most successful innovation of the last 50 years in university physics:

100% uptake in physics departments around the country.

Two personal stories

• Entropy and Second Law: “Change and chance” Using dice throwing and computer movies on a film loop.

• Quantum physics (Schrödinger equation, then exponential decay and accelerated motion, modeling ideas). Computers were obviously the future, but none in schools at the time.

Which gets the best results?

• 1 The Managerial Fallacy:

– Set ever-more demanding targets, monitor results closely (if you don’t say clearly what you want, how can you expect to get it?)

• 2 High expectations, not pre-specified

– Tell people to set their own goals (they may be more ambitious than you are!)

Trust matters!

Pathologies

• Management, efficiency, targets

– Today UK schools live or die by ‘student performance measures’

– In high stakes situations, people game the system

– Teachers teach students to counterfeit knowledge and understanding

• Physics education is not for sale

What have we learned since the Nuffield syllabus was devised?

• Understanding takes a long time and effort

• Teachers find it hard to change their habits

• Rewards and targets can have perverse effects: teachers can undermine your clever system

Familiarity and understanding

• Familiarity makes us feel that we understand

RULE:

“What I quickly and easily recognise is right”

• Easy access to what we know is essential

BUT

• Not all things familiar to us are correct

That was the problem with the pre-Nuffield syllabuses.

• Familiarity helps instant recognition:

“Rays of light travelling in straight lines”

 

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So what about this?

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• Wavy rays?

• We are looking at shadows, not at rays (which are anyway invisible)

(W. Kaminsky)

Familiarity

• HABITUAL EXAMPLES:

“Mass is the quantity of matter in a body”

“Energy is what makes things happen”

• Both are inadequate

• But what else can we say? Very annoying: they keep coming back!

• As we get used to ideas in physics, they come to seem more and more obvious

• When we started learning them they were very hard to understand!

EXAMPLE: Newton’s Laws

• We mostly don’t understand them much better now; they are just more familiar, so we just feel we understand.

Thinking, fast and slow

• Book by Daniel Kahneman (2011)

(Nobel Prize in Economics, for showing that people do not make reasoned decisions as economists think they must)

• Strong resonance with much research in physics education.

Fast thinking:

– Little effort, almost automatic

– Recognise things quickly (associative memory)

– Right often enough to have survival value, but not always right

– If not right, don’t care: “good enough is good enough”

– Does not probe more deeply: “What you see is all there is”

It’s RULE to judge truth:

• The easier and quicker it comes to mind, the more convincing it is

(Why constant repetition makes things seem plausible – politics works like this!)

• No place for evidence, argument, or needing to be consistent

• Biased towards immediate action on the most immediately available idea

Slow thinking

• has to be consciously turned on

• considers alternatives, weighs evidence, calculates, creates doubts

• takes effort. Eyes dilate, blood pressure rises! You take a deep breath before starting.

What is 17 x 24?

• With much practice, results of Slow thinking can become available to Fast thinking

(Expertise = familiarity with uncommon things)

Fast thinking (for rapid response):

– Works by activating associations in memory

– Looks for and infers and invents causes and intentions (“What’s going on here?”)

– Neglects ambiguity and suppresses doubt

– Is biased to believe and confirm

– Focuses on present evidence; ignores missing evidence

Physics Education Research

• Fast thinking invents causal stories

– “A movement needs a cause” (force?)

– Power of “linear causal reasoning” (Rozier & Viennot)

– “Echo explanations” (Viennot) Teachers explain using causal stories that Fast thinking easily accepts

Teachers exploit Fast thinking

• Rote learning produces familiarity

• Mnemonics get the answer without thought

• Vivid metaphors and analogies help

• Stories can mislead

• Are we teaching students to counterfeit understanding?

Slow thinking is needed for:

• Criticising

• Thinking of alternative possibilities

• Weighing up alternatives

• Finding error

AND

• Scientific knowledge relies on criticism

• Science runs on Slow

Educating Fast thinking

• Familiar habits govern much teaching (teach as you were taught)

• As well as comfortable, they feel right!

• “Teaching rituals” (Viennot)

• We sometimes have to look hard for a fresh approach

Archimedes Principle (an example of fast and slow thinking)

• Instant recognition; familiar routines

• Start with “Floating and sinking” experiments (what else could you do?)

PROBLEM

• “If heavy stuff sinks and light stuff floats how come metal boats don’t sink?”

• Nobody mentions pressure difference

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Helping Fast thinking

• Provide helpful new association:

“Pressure difference” (instead of “floating, sinking, density”)

• Link to memorable experiences and talk

• So recruit Fast thinking for future use in a helpful way

Fast thinking can’t be turned off which is why conceptions seem so stable and resistant)

• Need to choose situations well, to give Fast thinking really helpful things to associate with scientific ideas

• Plus some warning signals: “Beware, Slow thinking is needed here”

Coherence

• Coherence is crucial

– New ideas have to be consistent with everything else we know

– Scientific knowledge is an interconnected web

– Essential always to ask about connections

• Where are the exam questions asking about coherence (seeing mistakes, conflicts, assumptions)?

Challenges for the future

Tasks and prospects

• Reasons to change:

– Need to update content (new ideas, new technologies)

– Need to improve teaching of established topics (need to make teaching more coherent)

– Need to make physics more attractive

An awkward fact about physics

• Several of its most crucial theories seem to be rather inaccessible to the school curriculum

– Maxwell’s theory of e-m radiation

– Thermodynamics

– Quantum physics

– Relativity

Partial successes and failures of the Nuffield syllabus

• Quantum physics

• Thermodynamics

• Computational modelling

Quantum Physics

• Exploit Feynman’s “Many paths” story

• Crucial idea is that every process (path) has an amplitude and a phase

• Everything that can happen does happen

• Amplitudes combine taking account of phase

• Final amplitude (squared) gives probability

Thermodynamics

• The molecules don’t care

• What happens is what happens, inevitably, quite by chance

– molecules go from where there are a lot to where there are not (diffusion, mixing)

– Energy goes from where there is a lot to where there is not

– Some particles get lucky: Boltzmann distribution

Computational modelling

F = mg change only this line for new problem

a = F/m Newton

v = last(v) + adt kinematics

x = last(x) + vdt kinematics

t = last(t) + dt iteration

Why is the value of this so hard to see?

It has got almost nowhere in last forty years

Making physics more attractive

• Many have tried, but few have succeeded

– Harvard Project Physics (1960s) Liking decreased with more exposure (excuse: “too much of a good thing”)

• Young people’s attitudes form early and they resist efforts by their elders to change them.

Honesty and pride

• We have to express with honesty our pride and pleasure in physics:

– Intellectual satisfaction of dealing with difficulties

– Models and theories of astonishing power, depth, consistency, generality and parsimony

– Power of criticism from a physical standpoint

• Not populist, but honest

– Explore value of insisting that students be critical (yes, in exams too!)

Slogans

• Like politics, curriculum development needs slogans:

– “Hear and forget, see and remember, do and understand”

– “Science for all”

– “Discovery learning”

– “Ask Nature”

• Be wary of them: they rarely speak plainly (Mao Zedong)

• Be wary of projects that believe their own propaganda

• Instead, look for:

– Attention to detail

– Allowing for differences in circumstances

– Respect for and involvement of teachers

Getting it all right

• Communicate the big picture, to guide teachers’ choices

• The devil is in the detail: a small practical problem can ruin a grand plan

• Offer lots of teacher training. It is HARD to do new things in front of students. Provide ongoing support (e.g. email lists)

• Work on assessment from the start. It will carry your message in the end.

Give it time!

• Real curriculum change, which means changing people, takes time

• So:

Make Haste Slowly!

(Paul Black and Myron Atkin)

Finally…

Think hard

and

Do what you think is right!

On a personal note I was chatting to my husband about this topic. He didn’t do Nuffield physics but he did do Nuffield chemistry. He was happy that he didn’t have to learn loads of formulae and could concentrate on understanding the chemistry he was being taught. Helen Hare.

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