Language and understanding in Physics Acknowledgements: Brian McKittrick, Kim Falloon Helen McDonald & Geoff Davies

Student explanations and descriptions The momentum of the car caused the brick wall to break The passenger flew through the windscreen because of the accident When the starters gun went off, I pushed myself forward The force of the moving ball propelled it through the air The cup is stationary on the table due to the action of gravity and the equal and opposite reaction force due to the table The cup is stationary because the table is in the way

Force

Forces and objects A force acts on one object due to another object. For example the weight of an apple is the gravitational force acting on the apple due to the earth The table pushing up on the cup is the force on the cup by the table. This force is electrical by nature. The earth pulling down on the cup is gravitational in nature Force on cup by table Force on cup by earth

A: 1 kg B: 2.5 kg C: 3 kg earth Forces and objectsHow many vertical forces act on objects A, B and C respectively? What is the size and direction of all identified forces? table On AOn BOn C By A_10 N down 0 N By B10 N up_35 N down By C0 N35 N up_

Forces and objects Object B moving to the right at a constant speed is pulled to the right by a horizontal force Object B accelerates to the right is pulled to the right by a horizontal force

mass

weight The weight of an object is the force of gravity acting on it Does an apple weigh as much as the earth? What is meant by apparent weight?

Student explanations and descriptions The voltage passed through the globe causing it to glow The globe used up all the current The cell supplied energy to the charge as it passed through the cell The electricity moved around the circuit at the speed of light

potential difference, current Is potential difference the most difficult physics concept in secondary schools? The potential difference between two points in a circuit, for example the potential difference across the LED The current in the LED The resistance of the LED The power absorbed by the LED

Electricity – charge, motion and potential

Fields What is a field? A field is a physical quantity that has a value for each point in space and time.physical quantitypoint How is it used in secondary school physics? What are examples of fields? In what sense are they real? Can a field store potential energy? How does this description stand with the language used to describe lifting a mass in a gravitational field?

light What language do we use when we describe reflection and refraction? What language do we use when describing diffraction and interference? How do we deal with the particle model for light – the photon – for some interactions and retain a wave model of light for propagation? How do we talk about the photoelectric effect? How do we resolve G. I. Taylor’s experiment circa 1920’s? Is there a consistent language for use in modern physics? What would a candle look like to a group of observers if it emitted electromagnetic radiation at a rate of 1 photon per second?

inside the nucleus What is the nucleus composed of? Is it reasonable to think of the nucleus as being composed in individual protons and neutrons? Both the proton and the neutron are modelled as being composed of 3 quarks. A free neutron has a half-life against beta decay of about 10 minutes.

energy, kinetic and potential momentum An unbalanced force component acting on an object over a displacement gives rise to a change in the kinetic energy of the object. A net force acting on an object over a period of time gives rise to a change in the momentum of the object. What, if any, is the difference in the meaning of the words “unbalanced” and “net”?

task instruction Term DefinitionTypical learning examples AnalyseIdentify components, elements, constituent parts of the whole and identify the relationships between them Consider presented information and clarify concepts and knowledge; use qualitative and quantitative methods to distinguish between components (words, tables, labelled diagrams, calculations, graphs); recognise patterns; identify and relate implications; graphical analysis Apply Use knowledge (ideas, formulae, principles, theories, laws, models, techniques) in a new situation or context Propose a solution or response to a problem or issue; show steps; use algebraic and/or graphical methods as appropriate Calculate Use mathematical formulae and modelling to solve quantitative problems Solve numerical problems by using formulae and mathematical processes; find the numerical value of an unknown variable or constant Compare Identify the similarities and differences between two or more objects or processes List, tabulate or use a graphic organizer to identify similarities and differences Describe Communicate the characteristics and features of an event, object, procedure or process Use written or visual representations to communicate characteristics or features

Term DefinitionTypical learning examples Determine Find out, based on reasoning, observations and information Recognise a quantity (often without the use of calculations); interpolate; extrapolate; estimate Evaluate Make reasoned judgments or decisions on given or collected information, based on established criteria Assess the merit (strengths and limitations) of ideas, processes or procedures and reach a conclusion; validate evidence; choose from options based on reasoned arguments Explain Make clear; account for the reason for something or the relationship between cause and effect; state why and/or how Provide reasons mechanisms and outcomes, incorporate quantitative data as appropriate Identify Recognise particular elements of a whole or part; select from a number of possibilities; select relevant information or aspects of key ideas Recognise and name/label a specific object, element, component or underlying principle or concept; label/annotate components of a system, model or diagram Interpret Take a form of information and make conceptual meaning from it Derive meaning from information presented in multimodal texts (for example, written, aural and diagrammatic), tables, images and graphical formats ModelReproduce conceptual understandings and principles; physical structures and systems Construct a visual, physical, algebraic or graphical representation of concepts, principles or processes

References Physics questions without numbers, Dick Gunstone and Richard White, Faculty of Education, Monash University, 2012 Understanding and developing Science Teachers’ Pedagogical Content Knowledge; John Loughran, Amanda Berry and Pamela Mulhall Physics 1 and 2, Halliday and Resnick, Wiley