Baccalauréat international · IB Diploma

Physics · SL

Papers, samples and curriculum documents for this course. · ⁨Dossiers, échantillons et documents de programme pour ce cours.⁩

← Exams · ⁨Examens⁩

Course units and learning goals · ⁨Unités de cours et objectifs d'apprentissage⁩

These lessons teach selected course objectives. Check the remaining coverage gaps; the material is not a complete preparation programme. · ⁨Ces leçons abordent des objectifs de cours sélectionnés. Vérifiez les lacunes restantes en couverture ; ce matériel ne constitue pas un programme d'entraînement complet.⁩

Lessons · ⁨Leçons⁩ →Vocabulary practice · ⁨Pratique du vocabulaire⁩ →

A.1 · Kinematics

Rate of change of displacement.
The gradient of a displacement-time graph is velocity. The area under a velocity-time graph gives displacement. A constant-acceleration formula is valid only when its assumption is justified.
Choose a positive direction and state it. Use a light gate or video with a known scale and frame interval for repeatable motion measurements. Avoid assuming hand timing is exact over very short intervals.

velocity: Rate of change of displacement
acceleration: Rate of change of velocity

A.2 · Forces and momentum

Mass multiplied by velocity.
Impulse equals momentum change. Increasing stopping time for the same momentum change reduces average force. Identify external forces before applying momentum conservation.
Draw a free-body diagram containing only forces on the selected object. For spring measurements, add loads in steps within the elastic range and measure extension from the unloaded position.

momentum: Mass multiplied by velocity
resultant force: The vector sum of forces on an object

A.3 · Work, energy and power

Energy transferred per unit time.
Define the system and useful output before calculating efficiency. Doubling speed quadruples kinetic energy at constant mass. Power describes transfer per time, not total energy.
Measure a lifting height and load, time the lift, and record electrical input with suitable instruments. Repeat trials and account for heating or friction as transfers, not missing energy.

power · ⁨puissance⁩: Energy transferred per unit time
efficiency · ⁨efficacité⁩: Useful output divided by total input

B.1 · Thermal energy transfers

Energy per mass per temperature rise.
Temperature relates to particle motion in a model; internal energy includes kinetic and potential contributions. During a change of state, energy can change particle arrangements rather than temperature.
Measure mass, electrical input and temperature change for an insulated block. Ensure the temperature sensor has good contact, allow time for equilibration, and consider energy transferred to the surroundings.

specific heat capacity: Energy per mass per temperature rise
latent heat · ⁨chaleur latente⁩: Energy associated with a change of state

B.2 · Greenhouse effect

Actions addressing causes of environmental change.
Distinguish mitigation, which addresses drivers, from adaptation, which reduces harm from impacts. A policy assessment needs evidence about effectiveness, cost, equity and uncertainty; one criterion is not the entire decision.
Compare multi-year data using consistent baselines. State the region, timescale and uncertainty. At HL, connect a management decision to law, economics and ethics rather than treating these lenses as extra definitions only.

mitigation: Actions addressing causes of environmental change
adaptation: Actions reducing harm from environmental impacts

B.3 · Gas laws

Temperature on the kelvin scale.
At fixed amount and volume, pressure is proportional to kelvin temperature. At fixed temperature and amount, pressure is inversely proportional to volume. State which quantities are fixed before choosing a relationship.
Use approved apparatus with a temperature range and pressure limit set by the teacher. Allow thermal equilibrium and record pressure against kelvin temperature. Never heat an improvised sealed vessel.

absolute temperature: Temperature on the kelvin scale
ideal gas: A gas model with specified simplifying assumptions

B.5 · Current and circuits

Rate of flow of charge.
Current is the same through components in series. Potential differences add around the series path. In parallel, branches share the same potential difference, while branch currents sum at a junction.
Place an ammeter in series and a voltmeter in parallel. For an I-V investigation, change voltage in steps, reverse polarity when appropriate and limit current to reduce heating.

current · ⁨courant⁩: Rate of flow of charge
potential difference: Energy transferred per unit charge

C.1 · Simple harmonic motion

A large response to periodic forcing near a natural frequency.
Velocity is greatest near equilibrium for ideal SHM, while acceleration magnitude is greatest at extreme displacement. Resonance can occur near the natural frequency under periodic driving, with amplitude limited by damping.
Measure time for several complete oscillations and divide. Define a cycle consistently and use a small displacement when the model requires it. Keep pendulum paths clear and record damping effects rather than assuming perfect motion.

resonance · ⁨résonance⁩: A large response to periodic forcing near a natural frequency
damping: Energy transfer out of an oscillating system

C.2 · Wave model

Distance between successive points in phase.
At a boundary, frequency stays fixed by the source. A change of speed changes wavelength. Refraction follows from speed differences; angles are measured from the normal.
Measure several wavelengths and divide to reduce fractional reading uncertainty. Use a ray box with a normal drawn at the boundary. Keep the beam away from eyes and record incident and refracted angles clearly.

wavelength · ⁨longueur d'onde⁩: Distance between successive points in phase
frequency · ⁨fréquence⁩: Number of oscillations per unit time

C.3 · Wave phenomena

Distance between successive points in phase.
At a boundary, frequency stays fixed by the source. A change of speed changes wavelength. Refraction follows from speed differences; angles are measured from the normal.
Measure several wavelengths and divide to reduce fractional reading uncertainty. Use a ray box with a normal drawn at the boundary. Keep the beam away from eyes and record incident and refracted angles clearly.

wavelength · ⁨longueur d'onde⁩: Distance between successive points in phase
frequency · ⁨fréquence⁩: Number of oscillations per unit time

C.4 · Standing waves and resonance

A large response to periodic forcing near a natural frequency.
Velocity is greatest near equilibrium for ideal SHM, while acceleration magnitude is greatest at extreme displacement. Resonance can occur near the natural frequency under periodic driving, with amplitude limited by damping.
Measure time for several complete oscillations and divide. Define a cycle consistently and use a small displacement when the model requires it. Keep pendulum paths clear and record damping effects rather than assuming perfect motion.

resonance · ⁨résonance⁩: A large response to periodic forcing near a natural frequency
damping: Energy transfer out of an oscillating system

C.5 · Doppler effect

Shift of an identified line toward longer wavelength.
Compare a identified line with its laboratory rest wavelength. Use z = (observed−rest)/rest, then v approximately cz in the stated low-speed model. Do not apply this approximation without checking the regime or treating a cosmological redshift as a simple exact velocity.
Use attributed spectra with calibration and line identification. Compare several lines for a consistent shift. State uncertainty and distinguish relative line-of-sight motion from an unmeasured transverse component.

redshift: Shift of an identified line toward longer wavelength
rest wavelength: Wavelength of the line measured with no relative source motion

D.1 · Gravitational fields

A description of gravitational force per unit mass.
For a point mass or outside a spherical mass, field strength follows an inverse-square distance dependence. Use distance from the centre, not height above the surface alone.
State the circular-orbit approximation and ignore atmospheric drag only when justified. Draw the force toward the central body and velocity tangential to the orbit. Do not add an outward force merely because the path is circular.

gravitational field: A description of gravitational force per unit mass
centripetal force: Net force toward the centre of a curved path

D.2 · Electric and magnetic fields

Electric force per unit positive test charge.
In a uniform field between ideal parallel plates, E = V/d away from edge effects. The force is F = qE, so its direction reverses for a negative charge. Coulomb force between ideal point charges decreases with separation squared.
Sketch labelled plate polarities, field arrows and the charge before calculating. Convert separation to metres. In school, use simulations or approved low-voltage electrostatic models rather than exposed high-voltage equipment.

electric field strength: Electric force per unit positive test charge
test charge: A small charge used to probe an electric field

D.3 · Motion in electromagnetic fields

Force due to a magnetic field on a moving charge or current.
Equate magnetic force with mv²/r to obtain r = mv/(|q|B) for perpendicular motion. A stronger field makes a smaller radius at fixed momentum. Parallel entry gives zero magnetic force in this model.
Draw velocity, field and force as separate arrows using stated into/out-of-page conventions. Use supplied beam data or a simulation. Do not treat a current-carrying wire direction as identical to electron-motion direction.

magnetic force: Force due to a magnetic field on a moving charge or current
momentum: Mass multiplied by velocity in the classical model

E.1 · Structure of the atom

Wavelength pattern of radiation emitted by a source.
An emitted photon corresponds to a transition to a lower energy level. Absorption requires a compatible energy difference. Rutherford scattering supported a small dense nucleus, but that experiment alone did not establish the complete quantum model.
Read a labelled energy-level diagram before calculating. Keep joules and electronvolts distinct and use the given constants. Compare attributed spectra at a common wavelength scale and avoid looking at unsafe light sources.

emission spectrum: Wavelength pattern of radiation emitted by a source
energy level: An allowed energy state in a model

E.3 · Radioactive decay

Time for activity or undecayed population to halve.
Subtract background counts measured over the same time interval. Distinguish irradiation from contamination. Shielding, distance and reduced exposure time can reduce risk under a school-controlled procedure.
Use teacher-managed sources and the school radiation rules. Record count duration and repeat background measurements. Do not extrapolate a half-life from one nucleus or from uncorrected readings.

half-life: Time for activity or undecayed population to halve
background radiation: Radiation measured apart from the investigated source

E.4 · Fission

Splitting of a heavy nucleus into lighter nuclei.
Separate conservation of nucleon number from conservation of total energy. Released neutrons may initiate further fissions, escape or be absorbed. A controlled reactor and an uncontrolled chain reaction have different neutron-management conditions.
Balance a supplied nuclear equation, use the specified mass data and identify the system. Analyse models or published reactor data; this is not a school attempt to produce fission or handle reactor materials.

fission: Splitting of a heavy nucleus into lighter nuclei
chain reaction: A sequence in which products initiate further events

E.5 · Fusion and stars

Total emitted power.
For isotropic emission without absorption, flux follows an inverse-square relationship with distance. Observed brightness alone therefore cannot establish luminosity.
Keep distance units consistent, identify which quantities are intrinsic to the star, and distinguish observational evidence from a model of stellar evolution. Do not confuse a red giant stage with every possible final remnant.

luminosity · ⁨luminosité⁩: Total emitted power
flux: Power received per unit area

Practical · Experimental programme

A quantified limitation on a measured result.
For a product or quotient, adding fractional uncertainties is a common maximum-uncertainty approximation. For a difference, add absolute uncertainties. A nonzero intercept can reveal an offset or an incomplete model.
Show units on axes and choose a sensible scale. Plot uncertainty bars where justified, draw a best-fit line rather than joining every point, and estimate steepest and shallowest plausible gradients when the course method calls for them.

uncertainty: A quantified limitation on a measured result
systematic error: A consistent measurement bias

Preparing for this qualification · ⁨Préparation à cette qualification⁩

Use themes A–E and no old optional-topic model.
SL excludes A.4, A.5, B.4, D.4 and E.2. A.2, B.5, C.1/C.3/C.5, D.1/D.2 and E.1/E.3 include additional HL scope.
SL Paper 1: 1.5 h, Paper 2: 1.5 h; HL: 2 h, 2.5 h. Papers weigh 36% and 44%; individual investigation 20%, 3,000 words.
A clean current Physics data booklet and calculator are available in examinations; the booklet itself remains an acquisition item.
Practical work 20 h plus collaborative sciences project 10 h and investigation 10 h.

Teaching coverage still needed · ⁨Couverture pédagogique encore nécessaire⁩

Remaining understandings and guidance in the acquired 2025 Physics guide require complete authored coverage; exclude AHL statements even within mixed topics.
All tools/inquiry objectives and data booklet require complete assessment-linked coverage.

Specifications and sample documents · ⁨Spécifications et documents d'échantillon⁩

Physics — Subject guide · 2025 ↗
First assessment: 2025
Physics — Subject brief · 2025 ↗
First assessment: 2025

Course materials · ⁨Matériel pédagogique⁩

Course preparation · ⁨Préparation du cours⁩

Documents are available. Board-specific notes, assessments and interactive past-paper practice are not yet available for every course. · ⁨Les documents sont disponibles. Les notes spécifiques au conseil, les évaluations et la pratique interactive des anciens sujets ne sont pas encore disponibles pour tous les cours.⁩

Lessons · ⁨Leçons⁩ →