The initial knowledge state of college physics students
Halloun & Hestenes 1985Halloun, I. A., & Hestenes, D. · American Journal of Physics 53(11), 1043–1055 · doi:10.1119/1.14030
- What it found
- Students arrive with a coherent, stable, Aristotelian-flavoured theory of motion. Conventional instruction leaves much of it intact: the formalism is learned alongside the intuition rather than in place of it.
- What it changed here
- Each lesson names the specific intuition it is built to confront, and constructs a situation where that intuition makes a clearly wrong prediction.
Students' preconceptions in introductory mechanics
Clement 1982Clement, J. · American Journal of Physics 50(1), 66–71 · doi:10.1119/1.12989
- What it found
- The belief that motion implies a force in the direction of motion survives a full mechanics course in a large fraction of students, including those who can state Newton's laws correctly.
- What it changed here
- The Newton's-laws simulation shows a cart coasting on its track after the cord visibly releases, with an empty free-body diagram in the direction of travel: the case the belief cannot survive.
Curvilinear motion in the absence of external forces: Naive beliefs about the motion of objects
McCloskey et al. 1980McCloskey, M., Caramazza, A., & Green, B. · Science 210(4474), 1139–1141 · doi:10.1126/science.210.4474.1139
- What it found
- Asked what path a ball takes on leaving a curved tube, about half of college students, including some who had studied physics, drew a curving path, as though the object retained a memory of its circular motion; about a third did the same for a ball swung on a string.
- What it changed here
- The circular-motion simulation lets you cut the string and draws the predicted curve beside the actual tangent line.
Spontaneous reasoning in elementary dynamics
Viennot 1979Viennot, L. · European Journal of Science Education 1(2), 205–221 · doi:10.1080/0140528790010209
- What it found
- Students spontaneously supply a force in the direction of motion and treat it as proportional to the speed: a pattern that appears across countries, languages and curricula.
- What it changed here
- The Newton's-laws lesson trains the question 'which way is it accelerating?' in place of 'which way is it going?': the habit her force-follows-velocity pattern is built to break.
Investigation of student understanding of the concept of velocity in one dimension
Trowbridge & McDermott 1980Trowbridge, D. E., & McDermott, L. C. · American Journal of Physics 48(12), 1020–1028 · doi:10.1119/1.12298
- What it found
- In demonstration interviews, students judged which of two objects was faster by which was ahead, reading velocity off position, with the confusion surfacing exactly when one object passes the other.
- What it changed here
- Why the 1-D motion simulation names the regime, 'speeding up', 'slowing down', above the track, and why position, velocity and acceleration never share a colour anywhere on this site.
Investigation of student understanding of the concept of acceleration in one dimension
Trowbridge & McDermott 1981Trowbridge, D. E., & McDermott, L. C. · American Journal of Physics 49(3), 242–253 · doi:10.1119/1.12525
- What it found
- The companion interviews on acceleration: students routinely read acceleration off the velocity, momentarily at rest means no acceleration, moving faster means accelerating, rather than off its rate of change.
- What it changed here
- The turning point, where velocity is zero while acceleration is not, is a named confrontation in both the 1-D motion and simple-harmonic-motion lessons.
Student understanding of the work-energy and impulse-momentum theorems
Lawson & McDermott 1987Lawson, R. A., & McDermott, L. C. · American Journal of Physics 55(9), 811–817 · doi:10.1119/1.14994
- What it found
- Students who could state both theorems often could not apply them, and frequently treated energy as a substance that gets used up rather than a quantity that is transferred.
- What it changed here
- The energy simulation accounts for every joule on screen, including the thermal energy friction generates, so nothing ever appears to vanish.
Student understanding of rotational and rolling motion concepts
Rimoldini & Singh 2005Rimoldini, L. G., & Singh, C. · Physical Review ST Physics Education Research 1, 010102 · doi:10.1103/PhysRevSTPER.1.010102
- What it found
- Students reliably expect the heavier or larger body to win a rolling race, and struggle to separate angular from linear quantities.
- What it changed here
- The rolling race gives you mass and radius sliders that visibly change nothing about the outcome.
Student understanding of static equilibrium: Predicting and accounting for balancing
Ortiz et al. 2005Ortiz, L. G., Heron, P. R. L., & Shaffer, P. S. · American Journal of Physics 73(6), 545–553 · doi:10.1119/1.1862640
- What it found
- Asked whether a rigid body on a frictionless pivot will balance, students tended to compare the forces on each side rather than the torques, and the tendency persists after instruction, even in students who can compute torques on demand.
- What it changed here
- The rolling lesson puts its weight on torque where force-comparison goes nowhere: which racer needs more friction is settled by the torque each shape demands, not by anything about the forces' sizes.
Children's ideas about action at a distance
Bar et al. 1997Bar, V., Zinn, B., & Rubin, E. · International Journal of Science Education 19(10), 1137–1157 · doi:10.1080/0950069970191003
- What it found
- Gravity is widely believed to require air, or to stop somewhere above the atmosphere: ideas that persist into adulthood and into introductory courses.
- What it changed here
- The orbit simulation draws the gravitational force vector at every point of the orbit, including the far side, where it never disappears.
Learning about gravity I: Free fall
Kavanagh & Sneider 2007Kavanagh, C., & Sneider, C. · Astronomy Education Review 5(2), 21–52 · doi:10.3847/AER2006018
- What it found
- A review of decades of research on how ideas about gravity and falling develop, and how resistant the intermediate stages are to instruction.
- What it changed here
- Gravity is introduced as a force that never switches off, well before orbits appear.
Making sense of how students make sense of mechanical waves
Wittmann et al. 1999Wittmann, M. C., Steinberg, R. N., & Redish, E. F. · The Physics Teacher 37, 15–21 · doi:10.1119/1.880142
- What it found
- Students reason about a wave pulse as if it were an object, giving it the properties of a thrown ball, expecting the medium to travel with the disturbance.
- What it changed here
- The waves unit teaches a pulse as a disturbance rather than an object because of this paper: every element of the string is drawn at a fixed position, one of them marked, with its transverse velocity as the only velocity vector on screen, so the thing that arrives at the far end demonstrably never left the near one.
Charged poles?
Maloney 1985Maloney, D. P. · Physics Education 20(6), 310–316 · doi:10.1088/0031-9120/20/6/009
- What it found
- Given problems about electric charges moving between the pole faces of permanent magnets, students most often reasoned as though a north pole were itself positively charged and acted directly on nearby charges the way one electric charge acts on another; the next most common strategy had charges of either sign attracted to whichever pole was the stronger.
- What it changed here
- Grounds the 'charged pole' distractor in the force-direction checkpoint, and the decision to make a charge at rest in the field do absolutely nothing: a configuration the speed slider can reach, because a magnetic force that needs motion is exactly what this reasoning denies.
A study of tertiary physics students' conceptualizations of sound
Linder & Erickson 1989Linder, C. J., & Erickson, G. L. · International Journal of Science Education 11(5), 491–501 · doi:10.1080/0950069890110502
- What it found
- Phenomenographic clinical interviews with ten physics graduates entering a teacher-education programme, using everyday and school demonstrations of sound. Their conceptualizations included sound as a travelling entity rather than a disturbance of a medium: the earliest documentation of a conception that has since turned up in every study of how people think about sound.
- What it changed here
- Why this lesson treats "sound is a thing that moves through the air" as a serious answer worth a full rebuttal rather than a beginner's slip: it survives a physics degree. The checkpoint's feedback says so explicitly.
Spontaneous reasoning on the propagation of visible mechanical signals
Maurines 1992Maurines, L. · International Journal of Science Education 14(3), 279–293 · doi:10.1080/0950069920140305
- What it found
- Asked what governs how fast a signal runs along a rope or a spring, students explained the speed by the shape of the signal and the manner of its creation, how hard and how fast the flick was, rather than by the properties of the medium.
- What it changed here
- The wave-pulse simulation prints v = √(T/μ) on the canvas beside the statement that amplitude and pulse width do not appear in it, and the 'reaches the far end at' readout refuses to move when either of those two sliders does.
Confusion by representation: On student's comprehension of the electric field concept
Törnkvist et al. 1993Törnkvist, S., Pettersson, K.-A., & Tranströmer, G. · American Journal of Physics 61(4), 335–338 · doi:10.1119/1.17265
- What it found
- Shown canonical electric-field-line diagrams and asked to give the force on, and the trajectory of, a test charge, students did not hold apart the field line, the force vector, the velocity vector and the trajectory: the single drawn line was read as all four at once.
- What it changed here
- The electric-field simulation traces the field line through the launch point and integrates the charge's real motion at the same time, and reports the distance between the two curves as a live readout and a graph. Released from rest it is zero; launched across the field it grows by metres.
Development of a computer-based tutorial on the photoelectric effect
Steinberg et al. 1996Steinberg, R. N., Oberem, G. E., & McDermott, L. C. · American Journal of Physics 64(11), 1370–1379 · doi:10.1119/1.18360
- What it found
- Many students in a sophomore-level modern physics course could not interpret the photoelectric experiment in terms of a photon model of light, even after instruction. The conceptual and reasoning difficulties identified guided an interactive computer-based tutorial whose central instructional strategy was drawing and interpreting graphs of current against voltage for the circuit.
- What it changed here
- The simulation's automatic scan builds exactly that family of current-versus-voltage curves, one per wavelength, live beside the tube, and the lesson opens on the intensity-versus-energy confusion this study surfaced, before any formalism appears.
Development and assessment of a research-based tutorial on light and shadow
Wosilait et al. 1998Wosilait, K., Heron, P. R. L., Shaffer, P. S., & McDermott, L. C. · American Journal of Physics 66(10), 906–913 · doi:10.1119/1.18988
- What it found
- Students who could state that light travels in straight lines frequently could not apply a ray model to predict what appears on a screen; a tutorial built directly on those documented difficulties produced substantially better performance than the standard instruction it replaced.
- What it changed here
- Grounds the decision to make this simulation a working ray diagram rather than a photograph of a beam: the incident, reflected and refracted rays are drawn as rays, at their true angles, with the geometry that produces them exposed.
An investigation of student understanding of single-slit diffraction and double-slit interference
Ambrose et al. 1999Ambrose, B. S., Shaffer, P. S., Steinberg, R. N., & McDermott, L. C. · American Journal of Physics 67(2), 146–155 · doi:10.1119/1.19210
- What it found
- University students who had studied physical optics at introductory level and beyond often could not account for the pattern light makes on a screen after a single or double slit; many did not know whether to apply geometrical or physical optics to a given situation and inappropriately combined elements of both, and some difficulties were serious enough to preclude even a qualitative wave model for light.
- What it changed here
- The diffraction simulation puts a sin θ = mλ and d sin θ = mλ in the same coordinates with the same marked rays, so the two conditions can be compared instead of merged, and the canvas names which one is being marked and whether it locates dark bands or bright ones.
Addressing student difficulties in applying a wave model to the interference and diffraction of light
Wosilait et al. 1999Wosilait, K., Heron, P. R. L., Shaffer, P. S., & McDermott, L. C. · American Journal of Physics 67(S1), S5–S15 · doi:10.1119/1.19083
- What it found
- Evidence that university students frequently lack a functional understanding of the wave model for light, together with the design of research-based tutorials intended to build that model rather than supply more formulas.
- What it changed here
- The lesson derives the single-slit minimum condition by pairing sources across the aperture instead of quoting it, and the simulation draws light spreading from the slit in every direction, so the pattern is read off the wavefront rather than off the incident ray.
Learners' knowledge in optics: interpretation, structure and analysis
Galili & Hazan 2000Galili, I., & Hazan, A. · International Journal of Science Education 22(1), 57–88 · doi:10.1080/095006900290000
- What it found
- High-school students and preservice teachers were probed on light and vision before and after conventional instruction; their knowledge afterwards was best described as a hierarchy of alternative facets and schemes rather than a single coherent model, with the pre-instruction ideas largely surviving.
- What it changed here
- The lesson names each intuition out loud (angles from the surface, light being 'blocked', frequency changing, total internal reflection into the denser medium) instead of presenting the correct physics and hoping it displaces them.
Student understanding of the first law of thermodynamics: Relating work to the adiabatic compression of an ideal gas
Loverude et al. 2002Loverude, M. E., Kautz, C. H., & Heron, P. R. L. · American Journal of Physics 70(2), 137–148 · doi:10.1119/1.1417532
- What it found
- Asked what happens when masses are added to a piston sealing an insulated cylinder, few students recognised that the first law was relevant at all, and fewer still could use work to account for the temperature change; most reasoned instead from a misinterpretation of the ideal gas law, and many did not distinguish heat, temperature, work and internal energy.
- What it changed here
- The adiabatic-compression mode runs exactly that experiment: no reservoir is drawn, the heat readout sits at 0.00 J for the whole process, and the gas still climbs from 300 K to 624 K with the work readout accounting for every joule.
The object coordination class applied to wave pulses: Analysing student reasoning in wave physics
Wittmann 2002Wittmann, M. C. · International Journal of Science Education 24(1), 97–118 · doi:10.1080/09500690110066944
- What it found
- Interview and written-response analysis showing students use both event-like and object-like descriptions of wave pulses but reason predominantly from object properties: treating a pulse as a thing with a size and a weight rather than as a disturbance passing through a medium.
- What it changed here
- Every string element in the wave-pulse simulation is drawn at a fixed x, one of them marked on a dashed vertical rail with its transverse velocity as the only velocity vector on screen: the thing that arrives at the far end demonstrably never left the near one.
Helping students develop an understanding of Archimedes' principle. I. Research on student understanding
Loverude et al. 2003Loverude, M. E., Kautz, C. H., & Heron, P. R. L. · American Journal of Physics 71(11), 1178–1187 · doi:10.1119/1.1607335
- What it found
- After standard instruction in hydrostatics, many science and engineering majors still could not predict or explain whether a simple object would sink or float. Some of the difficulties were specific to the buoyant force; many others traced back to ideas, mass, volume, density, the forces a fluid exerts, that instruction assumes are already secure before hydrostatics begins.
- What it changed here
- The buoyancy simulation puts mass and size on sliders that visibly move the block's weight and visibly do not move the submerged fraction, and prints the density ratio beside that fraction so the two can be read as one number.
Investigation of students' reasoning regarding heat, work, and the first law of thermodynamics in an introductory calculus-based general physics course
Meltzer 2004Meltzer, D. E. · American Journal of Physics 72(11), 1432–1446 · doi:10.1119/1.1789161
- What it found
- Across written responses from 653 students and interviews with 32 more, students correctly learned that internal energy is a state function and then improperly over-generalised the idea to work and heat: most of those interviewed held that the net work done or net heat absorbed in a cyclic process must be zero, and no more than about 20 % applied the first law effectively even after instruction.
- What it changed here
- The thermodynamics simulation reports ΔU around a cycle as exactly zero beside a net work and a net heat that are emphatically not, and shows Q, W and ΔU as three separately computed quantities whose books visibly close at every step, so heat can never be read as something the gas stores.
Student understanding of symmetry and Gauss's law of electricity
Singh 2006Singh, C. · American Journal of Physics 74(10), 923–936 · doi:10.1119/1.2238883
- What it found
- Across 541 introductory students plus advanced undergraduates and teaching assistants, students conflate electric flux with electric field: reading a vanishing net flux as a vanishing field, with 55% claiming the field inside a uniformly charged hollow cube is zero everywhere. Asked to compare two Gaussian surfaces around one charge, they choose the larger for its area or the smaller for its stronger field rather than seeing the two cancel; and they treat the symmetry needed to extract E as though it were a condition on the law itself, applying it to finite cylinders and cubes where no such symmetry exists.
- What it changed here
- The whole design of the flux simulation. The flux and the strongest field on the same surface are separate readouts and separate graphs; the size slider moves the perimeter and area readouts while the flux readout does not budge; and a blob surface with no symmetry whatsoever still lands the integral on q_enc/ε₀.
The Gauss and Ampere laws: different laws but similar difficulties for student learning
Guisasola et al. 2008Guisasola, J., Almudí, J. M., Salinas, J., Zuza, K., & Ceberio, M. · European Journal of Physics 29(5), 1005–1016 · doi:10.1088/0143-0807/29/5/013
- What it found
- University students' trouble with Gauss's and Ampère's laws springs less from isolated misconceptions than from 'common-sense' reasoning applied to a formula. In the authors' words, students "establish a causal link between the charge … enclosed by any closed surface/path and the field at the points on that surface/path. They wrongly infer that the only sources of the field are those enclosed by the Gaussian surface or Amperian path", and from that, that a zero flux means the field on the surface is zero.
- What it changed here
- The simulation reports the strongest field on the surface beside the flux, so an outside charge visibly rewrites the field at every point of the boundary, the far side included, while leaving the total untouched. The lesson names both halves of the confusion rather than only the more familiar one.
Some student conceptions of electromagnetic induction
Thong & Gunstone 2008Thong, W. M., & Gunstone, R. · Research in Science Education 38(1), 31–44 · doi:10.1007/s11165-007-9038-9
- What it found
- Fifteen in-depth interviews with second-year physics students surfaced three previously unreported conceptions, among them that the induced current 'varies proportionately with current in solenoid' and that there must be 'contact' between magnetic flux and the external coil for any EMF to be induced.
- What it changed here
- Both of those beliefs are what this simulation is built to break: a stationary magnet with substantial flux threading the coil and exactly zero current, and a parked-at-maximum-flux configuration that reads 0.000 mV while the flux readout is at its peak.
Student ideas regarding entropy and the second law of thermodynamics in an introductory physics course
Christensen et al. 2009Christensen, W. M., Meltzer, D. E., & Ogilvie, C. A. · American Journal of Physics 77(10), 907–917 · doi:10.1119/1.3167357
- What it found
- Across four offerings of the same introductory calculus-based course, no more than 6 % of students gave completely correct answers about entropy changes of a system and its surroundings before instruction, and nearly two-thirds showed clear conservation-type reasoning about entropy: outcomes that changed little after ordinary instruction.
- What it changed here
- Cited only where the thermodynamics lesson hands off to entropy: it names, before the next lesson starts, the specific expectation the reader is most likely to arrive with: that entropy is a conserved quantity like energy.
Identifying students' mental models of sound propagation: The role of conceptual blending in understanding conceptual change
Hrepić et al. 2010Hrepić, Z., Zollman, D. A., & Rebello, N. S. · Physical Review Special Topics: Physics Education Research 6, 020114 · doi:10.1103/PhysRevSTPER.6.020114
- What it found
- Alongside the scientific wave model, introductory students hold an 'Entity' model in which sound is a self-standing thing distinct from the medium it travels through, plus hybrid models blending the two, which survive instruction.
- What it changed here
- The Doppler simulation draws every crest as a circle that stays centred on the spot where it was made while the source drives on and leaves it behind, so the disturbance and its maker are visibly separate objects rather than one thing being carried along.
Thai high-school students' misconceptions about and models of light refraction through a planar surface
Kaewkhong et al. 2010Kaewkhong, K., Mazzolini, A., Emarat, N., & Arayathanitkul, K. · Physics Education 45(1), 97–107 · doi:10.1088/0031-9120/45/1/012
- What it found
- Two diagnostic questions given to 220 year-11 students after instruction found persistent errors about the direction light propagates and how it refracts at an interface; only 22% could use a ray diagram qualitatively to locate an image, and just one student of the 220 identified the image position with sound reasoning.
- What it changed here
- The refraction simulation draws the normal as a dashed, labelled line with a right-angle mark, and strikes every angle arc from it: the convention students most often get wrong is made a visible part of the apparatus rather than a sentence in the caption.
Identifying and addressing student difficulties with hydrostatic pressure
Loverude et al. 2010Loverude, M. E., Heron, P. R. L., & Kautz, C. H. · American Journal of Physics 78(1), 75–85 · doi:10.1119/1.3192767
- What it found
- Written questions and interviews found that many undergraduates never build a correct account of pressure in a static liquid: in particular they struggle to identify the forces acting on the liquid and to relate those forces to pressure.
- What it changed here
- Pressure is drawn as arrows perpendicular to every face of the block, in equal-and-opposite side pairs, with the tank wall carrying a labelled pressure-versus-depth gradient, so pressure is a set of forces on surfaces before it is ever a number.
Geometrical reasoning in wave situations: The case of light diffraction and coherent illumination optical imaging
Maurines 2010Maurines, L. · International Journal of Science Education 32(14), 1895–1926 · doi:10.1080/09500690903271389
- What it found
- Two hundred French students aged 19–23, questioned after lessons on wave optics, repeatedly reverted to geometrical reasoning: they followed the rays of the incident light at a macroscopic level instead of reasoning at the level of elementary waves with the phase concept and the Huygens–Fresnel principle.
- What it changed here
- The aperture scene draws a fan of light leaving the slit in every direction rather than rays that stop at the aperture and resume as a pattern, and the lesson opens by naming the ray-and-shadow prediction before dismantling it.
Student understanding of the direction of the magnetic force on a charged particle
Scaife & Heckler 2010Scaife, T. M., & Heckler, A. F. · American Journal of Physics 78(8), 869–876 · doi:10.1119/1.3386587
- What it found
- Across a series of written and interview studies, students began at the same low level of performance whether the field was presented as magnetic poles or as field lines, but after instruction answered correctly more often in the field-line representation: in part because more students believed charges are attracted to magnetic poles than believed charges are pushed along field lines.
- What it changed here
- The field is drawn as a lattice of ⊙/⊗ glyphs and never as a bar magnet, and the 'the charge is pulled towards the nearer pole' answer is offered explicitly in a checkpoint so that it can be named and confronted rather than left unspoken.
Interference between electric and magnetic concepts in introductory physics
Scaife & Heckler 2011Scaife, T. M., & Heckler, A. F. · Physical Review Special Topics: Physics Education Research 7, 010104 · doi:10.1103/PhysRevSTPER.7.010104
- What it found
- Simple force-direction questions put to a university course at several points in the term found that, before magnetic-force instruction, most students answered that the magnetic force on a moving charge points along the magnetic field, and that after that instruction surprising numbers began answering that the electric force is perpendicular to the electric field. The two ideas interfere in both directions, and which way depends on which was taught most recently.
- What it changed here
- The Lorentz-force simulation draws v and F on the charge with the right angle marked between them at every instant, and its velocity-selector mode puts the electric and magnetic forces in one picture doing visibly different jobs: one along the field and changing the energy, one across the motion and changing nothing.
Consistency of students' conceptions of wave propagation: Findings from a conceptual survey in mechanical waves
Tongchai et al. 2011Tongchai, A., Sharma, M. D., Johnston, I. D., Arayathanitkul, K., & Soankwan, C. · Physical Review Special Topics: Physics Education Research 7, 020101 · doi:10.1103/PhysRevSTPER.7.020101
- What it found
- Across 902 students in seven groups, from high school to second-year university, wrong answers about wave propagation were not careless slips: students applied a small number of identifiable alternative conceptual models with high consistency from question to question.
- What it changed here
- Why this simulation confronts 'a standing wave is a wave that has stopped' by drawing the two travelling components with markers riding their crests, rather than by asserting the correction in prose.
Student understanding of wave behavior at a boundary: The relationships among wavelength, propagation speed, and frequency
Kryjevskaia et al. 2012Kryjevskaia, M., Stetzer, M. R., & Heron, P. R. L. · American Journal of Physics 80(4), 339–347 · doi:10.1119/1.3688220
- What it found
- Studying periodic waves crossing a boundary between two media, the authors found many students treat v = fλ as a mathematical identity to be rearranged and do not recognise how wavelength, frequency and propagation speed can be manipulated independently in an experiment.
- What it changed here
- The simulation gives a separate control to each: the medium sets v (tension and linear density, or air temperature), the geometry sets λ (length and harmonic), and f is what falls out, so the amplitude slider visibly moves the string without moving the frequency readout.
Identifying student difficulties with entropy, heat engines, and the Carnot cycle
Smith et al. 2015Smith, T. I., Christensen, W. M., Mountcastle, D. B., & Thompson, J. R. · Physical Review Special Topics: Physics Education Research 11(2), 020116 · doi:10.1103/PhysRevSTPER.11.020116
- What it found
- In upper-division thermal physics courses, surveys, homework and videotaped tutorial observations showed students struggling to connect the Carnot cycle to the second law: with particular difficulty reasoning about situations that are physically impossible, and with failures to distinguish a differential change in a state property from its net change around a cycle.
- What it changed here
- The efficiency readout sits beside 1 − T_c/T_h at every reachable setting, and a checkpoint asks the reader to spend as long as they like trying to beat it. The Carnot mode touches the bound exactly and never passes it, which is the point the study says students do not reach on their own.
Analyzing high school students' reasoning about electromagnetic induction
Jelicic et al. 2017Jelicic, K., Planinic, M., & Planinsic, G. · Physical Review Physics Education Research 13(1), 010112 · doi:10.1103/PhysRevPhysEducRes.13.010112
- What it found
- Nine high-school students were interviewed while observing, describing and explaining six electromagnetism demonstrations, three of them on induction; the analysis found many conceptual and reasoning difficulties, especially with recognising and explaining induction, and identified three student mental models that recurred across the interviews.
- What it changed here
- The lesson leads with a demonstration-shaped question answered before any simulation is shown, because these are the conditions under which the difficulties were documented: a student watching a real magnet and a real coil and trying to say what will happen.
Students' conceptual difficulties in hydrodynamics
Suarez et al. 2017Suarez, A., Kahan, S., Zavala, G., & Martí, A. C. · Physical Review Physics Education Research 13(2), 020132 · doi:10.1103/PhysRevPhysEducRes.13.020132
- What it found
- Hundreds of written exams and follow-up oral interviews with first-year engineering and science students, on the hydrodynamics of ideal fluids. The most important difficulties arise from an inability to link the kinematics of a moving fluid to its dynamics, and from not seeing how different regions of one system interact; among the patterns documented is treating the pressure in a MOVING liquid as though it were simply the hydrostatic value, with the flow playing no part.
- What it changed here
- Five manometers are tapped into the same pipe, fed by the same pump, and stand at different heights: the picture that a single "pump pressure" cannot explain. The Bernoulli sum is printed for both sections at once so the kinematic term and the dynamic term are visibly the two halves of one equation.
Analyzing high school students' reasoning about polarization of light
Matejak Cvenic et al. 2021Matejak Cvenic, K., Ivanjek, L., Planinic, M., Jelicic, K., Susac, A., & Hopf, M. · Physical Review Physics Education Research 17(1), 010136 · doi:10.1103/PhysRevPhysEducRes.17.010136
- What it found
- Twenty-seven Croatian students aged 18–19, interviewed after regular instruction on polarization of light, showed conceptual difficulties that survived teaching; they often based their explanations on remembered but misinterpreted common schematic representations of polarization rather than on any model of light.
- What it changed here
- The polariser scene draws the polarisation state of every beam segment explicitly (every-which-way before the first polariser, aligned to each transmission axis after it), so the picket-fence cartoon is replaced by a picture in which the middle polariser visibly re-orients the light instead of removing more of it.
Student reasoning in hydrodynamics: Bernoulli's principle versus the continuity equation
Schäfle & Kautz 2021Schäfle, C., & Kautz, C. · Physical Review Physics Education Research 17(1), 010147 · doi:10.1103/PhysRevPhysEducRes.17.010147
- What it found
- About 250 undergraduate engineering students were tested on steady pipe flow of an incompressible fluid. When a question involved gravity, dissipative effects or a visible pressure drop, a considerable number never invoked the continuity equation at all, the step needed to reach the right answer, and answered instead from assumptions about local pressure: formally ("lower pressure means higher velocity"), intuitively ("higher pressure leads to higher velocity"), or by analogy with a single thrown particle ("flow velocity decreases when flowing upwards or friction is present").
- What it changed here
- The fluid-flow simulation makes the continuity step impossible to skip: tracer rows released at a fixed interval have a spacing that IS the local speed, so the speed-up in the throat is watched rather than derived. The lesson then names all three of the paper's reasoning patterns as checkpoint distractors, including the uphill one, tested with a uniform pipe where continuity forbids any speed change at all.
Children's conceptions of heat and temperature
Erickson 1979Erickson, G. L. · Science Education 63(2), 221–230 · doi:10.1002/sce.3730630210
- What it found
- One of the earliest systematic accounts of how children explain heating and cooling: heat is understood as a substance-like, caloric thing that objects contain and that moves into and out of them, a framework that survives well past the age at which it is first taught otherwise.
- What it changed here
- The thermal simulation shows exactly one flow, proportional to the temperature difference, with one direction: nothing is ever drawn moving from the cold body to the hot one, because there is no substance there to move.
Potential difference and current in simple electric circuits: A study of students' concepts
Cohen et al. 1983Cohen, R., Eylon, B., & Ganiel, U. · American Journal of Physics 51(5), 407–412 · doi:10.1119/1.13226
- What it found
- Given a questionnaire on simple circuits, 145 high-school students, and their 21 physics teachers, reached for current as the primary concept and treated potential difference as a consequence of current rather than its cause, with the battery imagined as a source of constant current.
- What it changed here
- The circuits lesson puts the battery's fixed EMF first and lets the current fall out of it: the same battery with a different resistor gives a different current, and the meters on screen show it happening.
When heat and temperature were one
Wiser & Carey 1983Wiser, M., & Carey, S. · In D. Gentner & A. L. Stevens (Eds.), Mental Models. Lawrence Erlbaum Associates, Hillsdale NJ
- What it found
- A historical case study of the seventeenth-century Florentine Experimenters, whose theory of heat had no separation between how hot a thing is and how much heat is in it: the same undifferentiated concept students bring to the topic today, and one that took the science itself about a century to pull apart.
- What it changed here
- The thermal lesson treats the heat/temperature split as the hard part rather than a definition to be got past, and gives the two quantities separate, unmistakable representations on screen.
A study of children's understanding of electricity in simple DC circuits
Shipstone 1984Shipstone, D. M. · European Journal of Science Education 6(2), 185–198 · doi:10.1080/0140528840060208
- What it found
- An early survey of how school students picture current in a simple circuit, which established the models the field has argued about ever since, including the one in which current is gradually used up as it goes round, so that a lamp nearer the battery must get more of it.
- What it changed here
- The circuits simulation puts a counting gate before and after each resistor. They read the same number, whatever the resistors do, because nothing is consumed on the way round.
Student difficulties in understanding image formation by a plane mirror
Goldberg & McDermott 1986Goldberg, F. M., & McDermott, L. C. · The Physics Teacher 24(8), 472–481 · doi:10.1119/1.2342096
- What it found
- Individual demonstration interviews with a real plane mirror: students who could state the law of reflection could not use it to say what an observer standing in a particular place would actually see, and did not connect the lines of a ray diagram to the light that has to arrive at an eye.
- What it changed here
- The optics simulation draws and labels the backward extensions behind the mirror as dashed lines, so the two kinds of line on the canvas never blur together: one carries light, and one is a construction.
An investigation of student understanding of the real image formed by a converging lens or concave mirror
Goldberg & McDermott 1987Goldberg, F. M., & McDermott, L. C. · American Journal of Physics 55(2), 108–119 · doi:10.1119/1.15254
- What it found
- In interviews built round a lit bulb, a converging lens and a screen, only about a third of students recognised that even a small part of a lens still forms the whole image; the most popular answer to covering half the lens was "half a lens, half an image", and having just completed the optics course made no difference to the result.
- What it changed here
- The lens simulation has an aperture slider. Cover ninety per cent of the lens and the image stays where it was, the same size and the same way up, only the light-collected readout falls.
Research as a guide for curriculum development: An example from introductory electricity. Part I: Investigation of student understanding
McDermott & Shaffer 1992McDermott, L. C., & Shaffer, P. S. · American Journal of Physics 60(11), 994–1003 · doi:10.1119/1.17003
- What it found
- The investigation of university students' understanding of simple circuits that the Tutorials curriculum was built on: students could not apply a model of a complete circuit, reasoned locally, attending to one point and ignoring the rest, and sequentially, following the circuit element by element in the order it happened to be drawn.
- What it changed here
- The circuits simulation puts three gates on one loop and has them count the same charge, so there is nothing sequential to see, and the lesson trains the loop rule as the first move: write the rule for the whole circuit, then solve.
School students' understanding of key ideas about radioactivity and ionizing radiation
Millar 1994Millar, R. · Public Understanding of Science 3(1), 53–70 · doi:10.1088/0963-6625/3/1/004
- What it found
- A diagnostic test given to 144 sixteen-year-olds found many holding a conception of how radiation is absorbed that differs significantly from the accepted account, along with a widespread conflation of radioactive material with the radiation it emits.
- What it changed here
- Nothing in the simulation lets a decay spread: every square changes when its own nucleus decays and at no other time, and the misconception callout names the material-versus-radiation confusion directly.
Investigating a grade 11 student's evolving conceptions of heat and temperature
Harrison et al. 1999Harrison, A. G., Grayson, D. J., & Treagust, D. F. · Journal of Research in Science Teaching 36(1), 55–87 · doi:10.1002/(SICI)1098-2736(199901)36:1<55::AID-TEA5>3.0.CO;2-P
- What it found
- Students arrive with heat and temperature poorly differentiated, routinely using "heat" for the internal energy a body contains; this study follows one grade-11 student through a unit designed to separate them, and shows how much deliberate substitution of one concept for the other the separation takes.
- What it changed here
- The thermal lesson separates the two before anything else happens, and gives each its own thing on screen: temperature is the block's colour and its marker on the strip, energy transferred is the flow between them.
Student Understanding of Ionizing Radiation and Radioactivity
Prather & Harrington 2001Prather, E. E., & Harrington, R. R. · Journal of College Science Teaching 31(2), 89–93 · link
- What it found
- Interviews with college students identified specific difficulties with ionizing radiation and radioactivity, and mapped the ideas students bring to the topic before any instruction on it.
- What it changed here
- The lesson keeps the nucleus and what it emits apart at every turn: a decay in the grid never spreads to a neighbour, and the prose says plainly that the decayed nucleus becomes a different element rather than vanishing.
Student understanding of time in special relativity: Simultaneity and reference frames
Scherr et al. 2001Scherr, R. E., Shaffer, P. S., & Vokos, S. · American Journal of Physics 69(S1), S24–S35 · doi:10.1119/1.1371254
- What it found
- Across about 800 students in some 30 course sections, students at every level took the time of an event to be the moment a light signal from it reached an observer, which turns the relativity of simultaneity into a story about signal delays, and lets absolute and relative simultaneity sit side by side in the same head without conflict.
- What it changed here
- Neither panel of the relativity simulation is anybody's view. Each is a whole frame's worth of synchronised clocks drawn at one instant of that frame's time, so there is no signal-travel story available to explain the disagreement away.
Student understanding of quantum mechanics
Singh 2001Singh, C. · American Journal of Physics 69(8), 885-895 · doi:10.1119/1.1365404
- What it found
- A test given to 89 students at six universities, with follow-up interviews, at the end of a full year of upper-level quantum mechanics. Stationary states, eigenstates and the time dependence of expectation values were the hardest ideas, the difficulties were common across institutions and teaching approaches, and they traced to an inability to discriminate between related concepts and a tendency to over-generalise.
- What it changed here
- The particle-in-a-box simulation draws psi and |psi|^2 as separate, separately labelled curves so the two cannot be conflated, and puts a stationary state beside a two-level superposition: the second oscillates at 2*pi*hbar/(E2-E1), the first does not move at all, and both graphs say so.
Understanding of Elementary Concepts in Heat and Temperature among College Students and K-12 Teachers
Jasien & Oberem 2002Jasien, P. G., & Oberem, G. E. · Journal of Chemical Education 79(7), 889 · doi:10.1021/ed079p889
- What it found
- A survey spanning non-majors, lower- and upper-division science majors, and both prospective and practising K-12 teachers found the same misconceptions about thermal equilibrium, specific heat, heat capacity and heat transfer at every level, traceable in part to everyday uses of the words 'heat' and 'temperature'.
- What it changed here
- Temperature is never shown as a stored quantity. The readout is recomputed from the live velocity arrays every frame, so a reader can see that the only thing a thermometer could be counting here is ⟨v²⟩.
Student understanding of the ideal gas law, Part II: A microscopic perspective
Kautz et al. 2005Kautz, C. H., Heron, P. R. L., Shaffer, P. S., & McDermott, L. C. · American Journal of Physics 73(11), 1064–1071 · doi:10.1119/1.2060715
- What it found
- Many undergraduate science and engineering majors hold seriously flawed microscopic models for the pressure and temperature of an ideal gas; the paper identifies common mistaken ideas about the microscopic processes and shows research-based instruction improving understanding of the gas law, especially its substance independence.
- What it changed here
- The kinetic-theory simulation measures pressure from wall impulse and temperature from ⟨v²⟩ rather than printing either formula, and the lesson runs the same gas at the same temperature with molecular masses from 4 u to 131 u so that substance independence is watched rather than asserted.
Students' Beliefs About the Role of Atoms in Radioactive Decay and Half-life
Prather 2005Prather, E. E. · Journal of Geoscience Education 53(4), 345–354 · doi:10.5408/1089-9995-53.4.345
- What it found
- An investigation of what introductory students believe individual atoms are doing during radioactive decay and across a half-life. Their accounts rested on inaccurate mental models of atomic behaviour: the same models behind the widely reported failure to distinguish irradiation from contamination.
- What it changed here
- The simulation is a grid of individual nuclei rather than a curve: each square is one atom, it changes colour and element at the moment that atom decays, and it stays in the sample afterwards.
Why we should teach the Bohr model and how to teach it effectively
McKagan et al. 2008McKagan, S. B., Perkins, K. K., & Wieman, C. E. · Physical Review Special Topics - Physics Education Research 4(1), 010103 · doi:10.1103/PhysRevSTPER.4.010103
- What it found
- Examining student descriptions of atoms on final exams across several versions of a transformed modern-physics curriculum, the authors found that where the curriculum does not explicitly connect the different models of the atom, many students keep a Bohr-like planetary picture instead of the Schrodinger one.
- What it changed here
- Nothing in this simulation draws an orbit: the atom is its ladder of allowed energies, because a spectrum is evidence about energies and nothing else. The lesson closes by saying in as many words what the ladder does and does not claim, and hands off explicitly to the wave picture rather than leaving the planetary image standing.
University student and K-12 teacher reasoning about the basic tenets of kinetic-molecular theory, Part I: Volume of an ideal gas
Robertson & Shaffer 2013Robertson, A. D., & Shaffer, P. S. · American Journal of Physics 81(4), 303–312 · doi:10.1119/1.4775153
- What it found
- University students and K-12 teachers often treat the volume of a gas as something different from the volume of its enclosing container, and frequently justify incorrect answers with faulty statements about how the particles move.
- What it changed here
- The piston is drawn as one of the four walls, the area readout is the area those walls enclose, and a dimension line under the box measures that same region, so the gas's volume and the container's volume are never two different things on screen.
Student reasoning about electrostatic and gravitational potential energy: An exploratory study with interdisciplinary consequences
Lindsey 2014Lindsey, B. A. · Physical Review Special Topics: Physics Education Research 10(1), 013101 · doi:10.1103/PhysRevSTPER.10.013101
- What it found
- The same incorrect reasoning patterns turned up in students' written answers and interviews about electrostatic potential energy after instruction as in their answers about gravitational potential energy in mechanics: evidence that the energy idea was never built robustly enough the first time to survive being carried into a new context.
- What it changed here
- Electric potential energy is introduced here as the same bookkeeping the mechanics unit already did, not as a new quantity: U = qV, and K + U constant, applied to a charge on a rail the way it was applied to a cart on a track.
Research as a guide for curriculum development: An example from introductory spectroscopy. I. Identifying student difficulties with atomic emission spectra
Ivanjek et al. 2015Ivanjek, L., Shaffer, P. S., McDermott, L. C., Planinic, M., & Veza, D. · American Journal of Physics 83(1), 85-90 · doi:10.1119/1.4901977
- What it found
- A four-year investigation following more than 1000 students found serious and persistent difficulties in connecting a discrete line spectrum with a set of atomic energy levels: the step from knowing that atoms have levels to explaining why a spectroscope shows lines rather than a continuum.
- What it changed here
- The atomic-spectra simulation never shows a spectrum without its ladder. The photon flies from the transition arrow to the exact position on the strip where its line then appears, so the link between the two representations is an event the reader watches rather than a claim they are told.
University student reasoning about the basic tenets of kinetic-molecular theory, Part II: Pressure of an ideal gas
Robertson & Shaffer 2016Robertson, A. D., & Shaffer, P. S. · American Journal of Physics 84(10), 795–809 · doi:10.1119/1.4960215
- What it found
- An analysis of over a thousand written responses from university physics and chemistry students found that the justifications they give for changes in the pressure of an ideal gas vary widely in the extent to which they are mechanistic and consistent with kinetic-molecular theory.
- What it changed here
- Molecule–molecule collisions are a switch. Turning them off leaves the measured wall pressure essentially unchanged, which turns the most common non-mechanistic story about pressure into something a reader can test in one run.
Identifying student and teacher difficulties in interpreting atomic spectra using a quantum model of emission and absorption of radiation
Savall-Alemany et al. 2016Savall-Alemany, F., Domenech-Blanco, J. L., Guisasola, J., & Martinez-Torregrosa, J. · Physical Review Physics Education Research 12(1), 010132 · doi:10.1103/PhysRevPhysEducRes.12.010132
- What it found
- High-school students, university students and their own teachers share the same difficulties in explaining atomic spectra, and those difficulties concern three things at once: the model of the atom, the model of the radiation, and the model of the interaction between them.
- What it changed here
- All three are drawn on one canvas: the ladder of allowed energies, the photon at its own wavelength, and the transition that couples them. Absorption is presented as the identical pair of levels run backwards, with the dark lines landing exactly on the bright ones so the two experiments can be compared with a ruler.
Teaching and learning special relativity theory in secondary and lower undergraduate education: A literature review
Alstein et al. 2021Alstein, P., Krijtenburg-Lewerissa, K., & van Joolingen, W. R. · Physical Review Physics Education Research 17(2), 023101 · doi:10.1103/PhysRevPhysEducRes.17.023101
- What it found
- A synthesis of about forty studies of relativity teaching, with the recurring learning difficulties catalogued: among them treating time dilation and length contraction as one-sided things that happen only to the "moving" frame, and applying length contraction in every dimension even when the motion is one-dimensional.
- What it changed here
- The relativity simulation gives each frame an equal panel, so neither is the one things happen to, and contracts lengths along the direction of motion only, which is exactly what leaves the light clock a longer path to cover and time dilation something to explain.
Variability in student reasoning about radioactive decay as a stochastic process
Hull et al. 2026Hull, M. M., Jansky, A., & Hopf, M. · Physical Review Physics Education Research 22(1), 010102 · doi:10.1103/5yyz-hpx8
- What it found
- Surveys of Austrian high-school and US college students found the reading that half of a nucleus decays in one half-life to be common but context-dependent: cluster analysis of response patterns showed reasoning that shifts with the question rather than one stable misconception, supporting a knowledge-in-pieces account.
- What it changed here
- The two half-life checkpoints ask about a whole sample and about a single nucleus separately rather than assuming one answer covers both, and the grid draws nuclei that are whole or transmuted and never half of anything.