IB DP Physics · first assessment 2025
Course summary.
The whole course on one page: how the hours are shared out, what each topic covers at standard and higher level, with its equations, the practical program, and how it is all assessed. Anything in terracotta is higher level only.
This is an unofficial summary of the DP Physics guide, written in my own words and much shortened. It is not an IB publication. For the exact wording of an understanding, a limit or an assessment rule, read the guide itself.
Teaching hours
Standard level is 150 hours and higher level 240. HL students study everything in SL, plus the additional HL content.
Five topics have no standard level content: A.4, A.5, B.4, D.4 and E.2. Each topic lists the equations the data booklet gives for it; point at a symbol, or tap it, to see what it stands for. The constants and the rest of the booklet are in the annotated data booklet.
ASpace, time and motion
SL · 27 h HL · 42 h
A.1Kinematics SL + HL · 9 h
- Describing motion with position, displacement, velocity and acceleration; distance against displacement; instantaneous against average values.
- The four equations of motion for constant acceleration.
- Motion with uniform and non-uniform acceleration.
- Projectiles without fluid resistance, split into horizontal and vertical components: launched horizontally, upwards or downwards.
- Fluid resistance, qualitatively: its effect on the path, time of flight, range and terminal velocity.
Limits. Calculations only where resistance can be ignored, with constant g near the Earth’s surface. The equation of the trajectory is not needed.
Open the A.1 teaching deck →
A.2Forces and momentum SL + HL · 10 h
- Newton’s three laws; forces as interactions; free-body diagrams and the resultant force in one and two dimensions.
- Contact forces: normal force, friction (static and dynamic), tension, the Hooke’s-law force of a spring, viscous drag on a small sphere, and buoyancy.
- Field forces: weight, electric force and magnetic force.
- Momentum and its conservation; impulse; force as rate of change of momentum, including changing mass.
- Elastic and inelastic collisions and explosions, with their energy changes.
- Circular motion: centripetal acceleration and force, angular velocity, in horizontal and vertical circles.
Limits. Collisions are one-dimensional at SL and two-dimensional at HL. Not required: solving momentum and energy as simultaneous equations, banked surfaces, or points in a vertical circle other than the top and bottom.
Open the A.2 teaching deck →
A.3Work, energy and power SL + HL · 8 h
- Conservation of energy: \(\Delta E_\mathrm{total}=0\) for an isolated system, with every change final minus initial; work as a transfer of energy, using the component of force along the displacement; Sankey diagrams.
- Mechanical energy as kinetic, gravitational potential and elastic potential energy, conserved when there are no resistive forces.
- Power as the rate of doing work, and efficiency.
- Energy density of fuels.
Open the A.3 teaching deck →
A.4Rigid body mechanics HL only · 7 h
- Torque, rotational equilibrium, and angular acceleration from an unbalanced torque.
- Angular displacement, velocity and acceleration, with the equations for constant angular acceleration.
- Moment of inertia and Newton’s second law for rotation.
- Angular momentum, its conservation, and angular impulse.
- Rotational kinetic energy.
Limits. No vector treatment, though clockwise and counterclockwise matter. Moment-of-inertia formulas are given. Combined motion is limited to rolling without slipping.
Open the A.4 teaching deck →
A.5Galilean and special relativity HL only · 8 h
- Reference frames; Galilean relativity, its transformations and velocity addition.
- The two postulates of special relativity; the Lorentz transformations; relativistic velocity addition.
- The invariant space–time interval; proper time and proper length; time dilation and length contraction; the relativity of simultaneity.
- Space–time diagrams and world lines.
- Muon decay as experimental evidence.
Limits. No derivations. World lines are for constant velocity only, on diagrams with the time axis labeled ct.
Open the A.5 teaching deck →
BThe particulate nature of matter
SL · 24 h HL · 32 h
B.1Thermal energy transfers SL + HL · 6 h
- The molecular model of solids, liquids and gases; density.
- Kelvin and Celsius scales; temperature as a measure of the average kinetic energy of particles; internal energy.
- Specific heat capacity, specific latent heat and changes of phase.
- Conduction (with calculations), convection (described) and thermal radiation.
- Black-body radiation: the Stefan–Boltzmann law, luminosity, apparent brightness and Wien’s displacement law.
Open the B.1 teaching deck →
B.2Greenhouse effect SL + HL · 6 h
- The energy balance of a planet: emissivity, albedo, the solar constant, and why the mean incoming intensity is a quarter of it.
- The main greenhouse gases (methane, water vapor, carbon dioxide, nitrous oxide) and their natural and human sources.
- How these gases absorb infrared and re-emit it in all directions, explained by molecular energy levels and by resonance.
- The enhanced greenhouse effect from human activity.
Limits. Problems estimate an equilibrium temperature from the balance of incoming and outgoing radiation, including exchange between surface and atmosphere.
Open the B.2 teaching deck →
B.3Gas laws SL + HL · 6 h
- Pressure; amount of substance and the Avogadro constant.
- The ideal gas as a model; the three empirical gas laws and the ideal gas equation.
- Pressure explained by molecular collisions, and its link to the average speed of the molecules.
- Internal energy of an ideal monatomic gas.
- When a real gas behaves like an ideal one; changes shown on pressure–volume diagrams.
Open the B.3 teaching deck →
B.4Thermodynamics HL only · 8 h
- The first law, the work done when a gas changes volume, and the change in internal energy.
- Entropy, both from thermal energy and temperature and from counting microstates.
- The second law in its Clausius, Kelvin and entropy forms; irreversibility; local decreases in entropy.
- Isovolumetric, isobaric, isothermal and adiabatic changes.
- Heat engines, cyclic processes, efficiency and the Carnot limit.
Limits. Sign convention: \(Q\) is positive into the system and negative out; \(W\) is positive when done by the system and negative when done on it. \(\Delta U=U_\mathrm{f}-U_\mathrm{i}=Q-W\). Calculations use monatomic ideal gases only.
Open the B.4 teaching deck →
B.5Current and circuits SL + HL · 6 h
- Cells as sources of emf, chemical and solar; circuit diagrams.
- Current as a flow of charge; potential difference as work done per unit charge; conductors and insulators.
- Resistance, resistivity and Ohm’s law; ohmic and non-ohmic behavior; heating and power.
- Resistors in series and parallel; emf and internal resistance; thermistors, LDRs and potentiometers.
Limits. Direct current only. Meters are ideal unless a question says otherwise.
Open the B.5 teaching deck →
CWave behavior
SL · 17 h HL · 29 h
C.1Simple harmonic motion SL + HL · 3 h Additional HL · 4 h
- The conditions for simple harmonic motion and its defining equation.
- Period, frequency, angular frequency, amplitude and displacement.
- The period of a mass on a spring and of a simple pendulum.
- Energy changes during an oscillation, described without calculation.
Additional HL
- Phase angle.
- Displacement and velocity as functions of time.
- Calculating the total and potential energy.
Open the C.1 teaching deck →
C.2Wave model SL + HL · 3 h
- Transverse and longitudinal traveling waves; wavelength, frequency, period and wave speed.
- The nature of sound waves and of electromagnetic waves, and how mechanical and electromagnetic waves differ.
- Describing how particles of the medium move, using displacement against position and against time.
Open the C.2 teaching deck →
C.3Wave phenomena SL + HL · 5 h Additional HL · 6 h
- Wavefronts and rays; reflection, refraction and transmission at a boundary; diffraction round a body and through an aperture.
- Snell’s law, the critical angle and total internal reflection.
- Superposition; coherent sources; the path-difference conditions for interference; Young’s double slit.
Additional HL
- The single-slit diffraction pattern and its first minimum.
- How the single-slit pattern shapes the double-slit pattern.
- Multiple slits and diffraction gratings.
Limits. Normal incidence only. The single slit is rectangular and lit with monochromatic light.
Open the C.3 teaching deck →
C.4Standing waves and resonance SL + HL · 4 h
- Standing waves as the superposition of two identical waves traveling in opposite directions; nodes, antinodes, amplitude and phase.
- Standing wave patterns on strings and in open and closed pipes, by harmonic.
- Resonance: natural frequency and driving frequency.
- Damping, light, critical and heavy, and its effect on amplitude and resonant frequency.
Limits. The lowest mode is called the first harmonic; “fundamental” and “overtone” are not used. No end corrections; displacement nodes only.
Open the C.4 teaching deck →
C.5Doppler effect SL + HL · 2 h Additional HL · 2 h
- The Doppler effect for sound and for electromagnetic waves, shown with wavefront diagrams.
- The fractional change in frequency or wavelength of light when the relative speed is far below the speed of light.
- Shifts in spectral lines as evidence of how stars and galaxies move.
Additional HL
- The observed frequency of sound for a moving source and for a moving observer.
Limits. Source and observer never both move. Uses in medicine and radar are expected.
Open the C.5 teaching deck →
DFields
SL · 19 h HL · 38 h
D.1Gravitational fields SL + HL · 5 h Additional HL · 7 h
- Kepler’s three laws of orbital motion.
- Newton’s law of gravitation, and when an extended body can be treated as a point mass.
- Gravitational field strength and field lines.
Additional HL
- Gravitational potential energy and gravitational potential.
- Field strength as the potential gradient; work done in moving a mass.
- Equipotential surfaces and their relation to field lines.
- Escape speed and orbital speed.
- The effect of a small atmospheric drag on a satellite’s height and speed.
Limits. Orbits are circular. A resultant field is found only at points on the line joining two bodies.
Open the D.1 teaching deck →
D.2Electric and magnetic fields SL + HL · 8 h Additional HL · 6 h
- The two types of charge; Coulomb’s law; conservation of charge.
- Millikan’s experiment as evidence that charge is quantized.
- Charging by friction, by induction and by contact, and the role of earthing.
- Electric field strength, field lines and their density; the uniform field between parallel plates.
- Magnetic field lines for a bar magnet, a straight wire, a coil and a solenoid.
Additional HL
- Electric potential energy and electric potential.
- Field strength as the potential gradient; work done in moving a charge.
- Equipotential surfaces and their relation to field lines.
Open the D.2 teaching deck →
D.3Motion in electromagnetic fields SL + HL · 6 h
- A charged particle moving in a uniform electric field, in a uniform magnetic field, and in the two at right angles.
- The force on a moving charge and on a current-carrying conductor in a magnetic field.
- The force per unit length between parallel current-carrying wires.
Limits. Finding a particle’s charge-to-mass ratio from its path in a magnetic field is required.
Open the D.3 teaching deck →
D.4Induction HL only · 6 h
- Magnetic flux and Faraday’s law.
- The emf induced in a straight conductor moving across a field.
- Lenz’s law as a consequence of energy conservation.
- The sinusoidal emf of a coil rotating in a uniform field, and the effect of its rotation frequency.
Limits. Self-induction is qualitative only. Inductance and RL circuits are not required.
Open the D.4 teaching deck →
ENuclear and quantum physics
SL · 23 h HL · 39 h
E.1Structure of the atom SL + HL · 6 h Additional HL · 3 h
- The Geiger–Marsden–Rutherford experiment and the discovery of the nucleus.
- Nuclear notation.
- Emission and absorption spectra as evidence for discrete energy levels; photons and atomic transitions.
- Spectra as a record of chemical composition.
Additional HL
- Nuclear radius and the density of nuclear matter.
- Distance of closest approach, and where Rutherford scattering breaks down at high energy.
- The Bohr model of hydrogen: its energy levels and quantized angular momentum.
Open the E.1 teaching deck →
E.2Quantum physics HL only · 8 h
- The photoelectric effect as evidence that light behaves as particles; threshold frequency and work function.
- Diffraction of particles as evidence that matter behaves as waves; the de Broglie wavelength.
- Compton scattering as further evidence for the photon.
Limits. The features of the photoelectric effect that wave theory cannot explain must be discussed. The Compton formula is not derived.
Open the E.2 teaching deck →
E.3Radioactive decay SL + HL · 7 h Additional HL · 5 h
- Isotopes; binding energy, mass defect and the curve of binding energy per nucleon; mass–energy equivalence.
- The strong nuclear force.
- Random and spontaneous decay; alpha, beta and gamma decay and their equations; neutrinos and antineutrinos.
- The penetrating and ionizing ability of each radiation.
- Activity, count rate and half-life, for whole numbers of half-lives; background radiation.
Additional HL
- Evidence for the strong nuclear force; the neutron-to-proton ratio and stability.
- Discrete nuclear energy levels from alpha and gamma spectra; the continuous beta spectrum as evidence for the neutrino.
- The decay constant, the exponential decay law and its link to half-life, for any time interval.
Limits. The weak nuclear force is not part of the course.
Open the E.3 teaching deck →
E.4Fission SL + HL · 4 h
- Energy released in spontaneous and neutron-induced fission.
- Chain reactions.
- The parts of a nuclear power plant: control rods, moderator, heat exchanger and shielding.
- The products of fission and how they are managed, including long-term storage of waste.
Open the E.4 teaching deck →
E.5Fusion and stars SL + HL · 6 h
- The balance in a star between outward radiation pressure and inward gravity.
- Fusion as the energy source of stars, and the density and temperature it needs.
- How a star’s mass decides its evolution.
- The regions of the Hertzsprung–Russell diagram.
- Stellar parallax for distance; finding a star’s radius from its luminosity and temperature.
Limits. Cepheid variables are not required.
Open the E.5 teaching deck →
Experimental program and skills
Practical work SL 20 h · HL 40 h
Hands-on experiments, simulations, databases and modeling, spread through the course so that practical skills grow alongside the content.
Collaborative sciences project 10 h
An interdisciplinary project with students of the other sciences, working together on a real-world problem. It does not count towards the final grade.
Scientific investigation 10 h
The student’s own investigation, written up as a report. This is the internal assessment.
Assessment
Two written papers make up 80% of the grade and the internal assessment 20%, at both levels.
In the examinations
- SL papers test standard level content only. HL papers test standard level and additional HL content.
- Papers 1A and 1B come as two booklets and are sat together in one session.
- No marks are taken off for a wrong multiple-choice answer.
- A calculator is allowed in every paper.
- Every student has a clean copy of the data booklet in every paper.
Assessment objectives
- AO1 · Show knowledge.
- AO2 · Understand and apply that knowledge.
- AO3 · Analyze, evaluate and synthesize.
- AO4 · Use the skills needed to carry out an investigation.
Each paper is split about evenly between AO1 with AO2, and AO3. AO4 is assessed only through the internal assessment, which covers all four.
Internal assessment
One task, the same at SL and HL: the scientific investigation. It is marked by the teacher and moderated by the IB.
The task
- The student writes and answers a research question of their own.
- It must involve collecting and analyzing quantitative data.
- The data can come from laboratory work, fieldwork, a spreadsheet model, a database or a simulation, alone or combined.
- The topic need not go beyond the content of the course.
- About 10 hours of teaching time are set aside for it.
The report
- At most 3000 words.
- Not counted: charts and diagrams, data tables, equations and calculations, citations, the bibliography and headers.
- It starts with the title, the candidate code (and those of any group members) and the word count. No cover page or contents page is needed.
- Sources must be referenced. The same work cannot also be used for the extended essay.
Working with others
- Group work is optional, in groups of at most three.
- Each student still needs a research question of their own, for example a different independent or dependent variable, or different data from a shared set.
- No two students may present the same raw data.
- The report is written individually. A group report is not allowed.
- The teacher reads and comments on one draft, without editing it. The next version handed in is final.
