93 IB Physics IA ideas and Extended Essay topics

Pendulum: when does the small-angle rule break?

The textbook period formula quietly assumes a tiny swing; find out how big a swing it can survive.

SL ●●●HL ●●●Lab + Modelling

C.1 Simple harmonic motionA.2 Forces and momentum

Also works as an EEOverused: needs a twistFull guide

Projectile: is the best launch angle really 45 degrees?

The 45-degree rule holds only when launch and landing heights match; real launchers rarely do.

SL ●●●HL ●●●Lab + Modelling

A.1 Kinematics

Overused: needs a twistFull guide

Friction: is the coefficient really a constant?

Textbooks say friction does not depend on contact area or speed. Test where that stops being true.

SL ●●●HL ●●●Lab

A.2 Forces and momentum

Full guide

Trolley on a ramp: how much energy does friction take?

Potential energy never fully turns into motion. Measure what goes missing and where.

SL ●●●HL ●●●Lab

A.3 Work, energy and powerA.1 Kinematics

Full guide

Mass on a spring: does the spring's own mass matter?

The 'massless spring' is a lie. Measure how much the spring's own mass changes the period.

SL ●●●HL ●●●Lab

C.1 Simple harmonic motion

Overused: needs a twistFull guide

Paper cones: what sets the terminal speed?

A falling paper cone stops accelerating quickly. Find which property of the cone controls its final speed.

SL ●●●HL ●●●Lab

A.2 Forces and momentumA.1 Kinematics

Full guide

Colliding carts: how much energy goes missing for each mass ratio?

Two carts stick together; the lost energy depends on a simple ratio. Check that it really does.

SL ●●●HL ●●●Lab

A.2 Forces and momentumA.3 Work, energy and power

Rolling down a slope: how does mass distribution set the speed?

A solid rod and a hollow tube race down the same ramp. Measure how the inner radius decides the winner.

SL ●●●HL ●●●Lab + Modelling

A.4 Rigid body mechanics HLA.1 Kinematics

Also works as an EE

Rope round a post: how much does each wrap multiply the grip?

A few turns of rope round a pole let a small hand hold a heavy load. The grip grows exponentially.

SL ●●●HL ●●●Lab + Modelling

A.2 Forces and momentum

Damped pendulum: which drag law fits the swing?

A pendulum with a big flat bob stops far faster than a compact one. Work out which drag model fits the decay.

SL ●●●HL ●●●Lab + Modelling

C.1 Simple harmonic motionC.4 Standing waves and resonance

Also works as an EETried by our studentsFree full card

Resonance tube: how long is the air column really?

The sound does not stop exactly at the open end of a tube. Measure how far beyond it effectively does.

SL ●●●HL ●●●Lab

C.4 Standing waves and resonanceC.2 Wave model

Full guide

Vibrating string: is f really proportional to 1/L?

A guitarist shortens a string to raise its pitch. Test the exact rule across a wide range.

SL ●●●HL ●●●Lab

C.4 Standing waves and resonanceC.2 Wave model

Full guide

Sound level and distance: does 1/r^2 hold?

The inverse-square law is textbook; real rooms rarely obey it. Find where it holds and where it breaks.

SL ●●●HL ●●●Lab + Fieldwork

C.2 Wave modelC.3 Wave phenomena

Full guide

Blowing across a bottle: how does the note depend on the water level?

Fill a bottle with water and the hum rises in pitch. Check that the pitch follows a precise law.

SL ●●●HL ●●●Lab + Modelling

C.4 Standing waves and resonanceC.2 Wave model

Also works as an EE

Doppler on a spinning speaker: how big is the shift?

Swing a small buzzer in a circle and the pitch wobbles. The size of the wobble tells you the speed.

SL ●●●HL ●●●Lab + Modelling

C.5 Doppler effectA.2 Forces and momentum

Also works as an EE

Where you pluck matters: how do the harmonics change?

Pluck a string in the middle and some overtones vanish. Measure how the spectrum depends on pluck position.

SL ●●●HL ●●●Lab + Modelling

C.4 Standing waves and resonanceC.2 Wave model

Also works as an EEFree full card

Salt and ice: how fast does a block melt in brine?

Salt changes how ice melts; measure how much and why.

SL ●●●HL ●●●Lab

B.1 Thermal energy transfers

Full guide

Insulation: does double the layer halve the loss?

More insulation helps, but there are diminishing returns. Find the pattern.

SL ●●●HL ●●●Lab + Modelling

B.1 Thermal energy transfers

Full guide

Electric kettle: how much of the energy really heats the water?

A kettle's label says the power; the water tells the truth. Measure its efficiency.

SL ●●●HL ●●●Lab + Modelling

B.1 Thermal energy transfersB.5 Current and circuits

Egg-drop physics: how does foam thickness change the impact force?

A thin foam pad barely helps; a thick one saves the egg. See the law that links them.

SL ●●●HL ●●●Lab

A.2 Forces and momentumA.3 Work, energy and power

Hot mug: how much cooling is evaporation?

A coffee cools mostly from the surface, not through the walls. Prove which loss wins.

SL ●●●HL ●●●Lab

B.1 Thermal energy transfers

Pencil traces: how well does graphite conduct?

A pencil line is a resistor with a strange shape. Measure how its resistance depends on length and pencil grade.

SL ●●●HL ●●●Lab

B.5 Current and circuits

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Wire resistance: does R really scale with length?

Resistance should double when the wire does. Test it across a wide range and find what fights back.

SL ●●●HL ●●●Lab

B.5 Current and circuits

Overused: needs a twistFull guide

Capacitor discharge: what sets the time constant?

A capacitor drains exponentially. Find what the time constant depends on and how well the law holds.

SL ●●●HL ●●●Lab

B.5 Current and circuits

Full guide

Metal wire: how much does its resistance rise with temperature?

A copper coil heats up and its resistance climbs. Measure the temperature coefficient yourself.

SL ●●●HL ●●●Lab

B.5 Current and circuitsB.1 Thermal energy transfers

Also works as an EETried by our studentsFree full card

Thermistor: can you pull out its hidden energy gap?

A thermistor's resistance plummets with temperature. The slope of the log plot reveals a material constant linked to an activation energy.

SL ●●●HL ●●●Lab

B.5 Current and circuitsB.1 Thermal energy transfers

Also works as an EE

Cell internal resistance: what changes it?

A battery has hidden resistance inside it; make it visible and see what it depends on.

SL ●●●HL ●●●Lab

B.5 Current and circuits

Overused: needs a twist

Light bulb: how hot is the filament?

A bulb's resistance climbs as it glows. Use it to estimate the filament temperature without a thermometer.

SL ●●●HL ●●●Lab + Modelling

B.5 Current and circuitsB.2 Greenhouse effect

Also works as an EE

Smoothing capacitor: how much ripple is left?

A rectifier makes lumpy DC. The capacitor smooths it, but by how much?

SL ●●●HL ●●●Lab

B.5 Current and circuits

Home-made capacitor: does C really go as 1/d?

Two foil sheets and some spacers make a capacitor. See how its capacitance changes as you pull the sheets apart.

SL ●●●HL ●●●Lab

B.5 Current and circuitsD.2 Electric and magnetic fields

Also works as an EE

Refraction: how closely does light obey Snell's law?

Snell's law is exact for ideal materials; find how close a real block gets and where it frays.

SL ●●●HL ●●●Lab

C.3 Wave phenomena

Overused: needs a twistFull guide

Single slit: how does the pattern width change with a?

A narrower slit makes a wider pattern. Test the 1/a law quantitatively.

SL ●●●HL ●●●Lab + Modelling

C.3 Wave phenomena

Also works as an EEFull guide

Light through a dye: how does absorption change?

A food-colouring solution blocks more light as it gets stronger; find out how simply.

SL ●●●HL ●●●Lab

C.2 Wave model

Full guide

Diffraction by a wire: can a laser measure a human hair?

A thin obstacle makes the same pattern as a slit of the same width. Use that to measure the very small.

SL ●●●HL ●●●Lab

C.3 Wave phenomena

Two polarisers: does the light follow cosine squared?

Cross two polarising sheets and the light vanishes. Measure the full angle dependence.

SL ●●●HL ●●●Lab

C.3 Wave phenomena

Sugar solution: how does refractive index rise with concentration?

Sweeter liquids bend light more. Make a hollow prism and measure by how much.

SL ●●●HL ●●●Lab

C.3 Wave phenomena

Also works as an EE

A CD as a grating: can you measure the width of its tracks?

The rainbow on a disc comes from a grating of microscopic grooves. Use it to measure them.

SL ●●●HL ●●●Lab

C.3 Wave phenomena

Free full card

Bulb colour: can the colour of light tell you its temperature?

A hotter filament looks whiter. Check that the colour ratio follows Planck's curve.

SL ●●●HL ●●●Lab + Modelling

B.2 Greenhouse effect

Also works as an EE

Hooke's law: where does the spring stop obeying it?

The linear law only works for a while. Find the limit and what happens beyond it.

SL ●●●HL ●●●Lab

A.2 Forces and momentumA.3 Work, energy and power

Overused: needs a twist

Rubber band: how much energy does a stretch cycle lose?

Stretch a rubber band and let it go: the return path is different. The gap between them is lost energy.

SL ●●●HL ●●●Lab + Modelling

A.3 Work, energy and powerB.1 Thermal energy transfers

Also works as an EEFree full card

Bending a ruler: can its stiffness be measured by deflection?

A longer ruler bends far more under the same load. The pattern gives the material's stiffness.

SL ●●●HL ●●●Lab + Modelling

A.2 Forces and momentum

Also works as an EE

Hourglass: how does sand flow depend on the hole size?

Sand runs at a steady rate regardless of how full the top is. The hole size sets that rate by a surprising power.

SL ●●●HL ●●●Lab + Modelling

A.2 Forces and momentum

Also works as an EE

Ripple tank: how does depth change the wave speed?

Waves slow down in shallow water. Find the rule connecting depth and speed.

SL ●●●HL ●●●Lab + Modelling

C.2 Wave modelC.3 Wave phenomena

Full guide

Draining bottle: how long does the water take to run out?

A bottle with a hole empties in a curve that hides a square root. Check it.

SL ●●●HL ●●●Lab

A.1 KinematicsA.2 Forces and momentum

Overused: needs a twist

Ball in syrup: how does terminal speed depend on size?

Sink a ball bearing into a thick liquid and it quickly settles to a steady speed.

SL ●●●HL ●●●Lab

A.2 Forces and momentum

Also works as an EEFree full card

Capillary tubes: does height rise as 1/radius?

Water climbs a thin tube against gravity. The thinner the tube, the higher it goes.

SL ●●●HL ●●●Lab

A.2 Forces and momentum

Kitchen-sink jump: how does the ring radius depend on flow?

Water from a tap makes a circular ring on a plate. Measure how that ring changes with the flow.

SL ●●●HL ●●●Lab + Modelling

A.2 Forces and momentumA.1 Kinematics

Also works as an EE

Cooling water: how well does Newton's law fit?

Hot objects cool faster when they are hotter, but how well does the simple model hold?

SL ●●●HL ●●●Lab + Modelling

B.1 Thermal energy transfers

Overused: needs a twistFull guide

Specific heat capacity: can you beat the heat loss?

Heating a metal block seems easy. The real challenge is accounting for the energy that escapes.

SL ●●●HL ●●●Lab

B.1 Thermal energy transfersB.5 Current and circuits

Overused: needs a twistFull guide

Trapped air: does pressure times volume stay constant?

Boyle's law is simple on paper; real syringes show what the assumptions hide.

SL ●●●HL ●●●Lab

B.3 Gas laws

Overused: needs a twistFull guide

Heat along a rod: how does temperature fall with distance?

Heat one end of a metal rod and watch the temperature drop along it. The shape of the curve tells you what escapes.

SL ●●●HL ●●●Lab + Modelling

B.1 Thermal energy transfers

Also works as an EE

Metal rod: how much does it grow when it is heated?

Rails buckle in summer. Measure how much a rod stretches per degree.

SL ●●●HL ●●●Lab

B.1 Thermal energy transfers

Free full card

Pressure and temperature: can you find absolute zero?

Gas pressure falls with temperature. Extrapolate far enough and it should vanish.

SL ●●●HL ●●●Lab

B.3 Gas laws

Overused: needs a twist

Planet shadows: do transit depths match the published radii?

A planet crossing its star dims it by a tiny amount. Check that the dip you measure matches the size the catalogue claims.

SL ●●●HL ●●●Database + Modelling

E.5 Fusion and starsA.1 Kinematics

Also works as an EE

Kepler's third law beyond the Sun: can orbits weigh distant stars?

Planets around other stars follow the same law as ours. Their orbits reveal the star's mass.

SL ●●●HL ●●●Database + Modelling

D.1 Gravitational fieldsA.2 Forces and momentum

Also works as an EE

Weighing planets: can moon orbits give Jupiter's mass?

A planet's moons orbit under its gravity, so their periods reveal its mass.

SL ●●●HL ●●●Database + Modelling

D.1 Gravitational fields

Also works as an EE

Star cluster in Gaia: how far away is it?

A cluster's stars lie on a clean main sequence. Compare its distance from parallax and from fitting the sequence.

SL ●●●HL ●●●Database + Modelling

E.5 Fusion and starsB.2 Greenhouse effect

Also works as an EE

Satellites from low orbit to geostationary: does T^2 follow a^3?

Hundreds of satellites share one law. Use their public orbital data to test it and weigh the Earth.

SL ●●●HL ●●●Database + Modelling

D.1 Gravitational fieldsA.2 Forces and momentum

Also works as an EEFree full card

Solar cell: does output follow the cosine of the angle?

Tilting a solar cell should reduce its power in a simple way. Check how well that holds.

SL ●●●HL ●●●Lab

B.2 Greenhouse effectB.5 Current and circuits

Full guide

Solar cell: where is the sweet spot for the load?

A solar cell gives most power at one load only. Find where, and how it moves with the light.

SL ●●●HL ●●●Lab + Modelling

B.5 Current and circuitsB.2 Greenhouse effect

Also works as an EE

Small wind turbine: does power rise as the cube of the wind speed?

Double the wind and you should get eight times the power. Measure how well a small turbine follows that.

SL ●●●HL ●●●Lab

A.3 Work, energy and powerB.5 Current and circuits

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Peltier chip as a generator: how much voltage per degree?

A cooling module also produces electricity from a temperature difference. Measure by how much.

SL ●●●HL ●●●Lab

B.1 Thermal energy transfersB.5 Current and circuits

Also works as an EE

Tide data: can you rebuild the tide from a few sine waves?

Tides look chaotic but come from a few clean oscillations. Pull them out of a month of sea-level data.

SL ●●●HL ●●●Database + Modelling

C.1 Simple harmonic motionD.1 Gravitational fields

Also works as an EE

Coil: how does the central field depend on current?

Double the current and the field should double. Test it across a wide range and find what bends the line.

SL ●●●HL ●●●Lab

D.2 Electric and magnetic fields

Full guide

Solenoid: does doubling the turns double the field?

A longer coil should give a proportionally stronger field. Find out how far that goes.

SL ●●●HL ●●●Lab

D.2 Electric and magnetic fields

Full guide

Two magnets: how does the force fall with distance?

Magnets pull harder the closer they are. Find the pattern of that fall, and where simple laws fail.

SL ●●●HL ●●●Lab + Modelling

D.2 Electric and magnetic fields

Also works as an EEFull guide

Magnet in a copper tube: how slow is its fall?

A magnet drops slowly through a copper tube with no friction. Eddy currents do the braking.

SL ●●●HL ●●●Lab + Modelling

D.4 Induction HLA.2 Forces and momentum

Also works as an EEFull guide

Magnet through a coil: what sets the size of the pulse?

Drop a magnet through a coil and a voltage pulse appears. See how its height depends on the drop.

SL ●●●HL ●●●Lab + Modelling

D.4 Induction HL

Also works as an EE

Transformers: how close to ideal is the turns ratio?

The voltage ratio should match the turns ratio, but real cores leak.

SL ●●●HL ●●●Lab

D.4 Induction HL

Free full card

Magnet on an aluminium slope: does it slide at a steady speed?

A magnet slides slowly down a metal ramp. The drag grows with speed, as in syrup.

SL ●●●HL ●●●Lab + Modelling

D.4 Induction HLA.2 Forces and momentum

Also works as an EE

LED colours: can you measure Planck's constant?

Each colour of LED turns on at a different voltage. That pattern holds a famous constant.

SL ●●●HL ●●●Lab

E.2 Quantum physics HLB.5 Current and circuits

Full guide

Photoelectric effect: stopping voltage vs frequency

Light can knock electrons out of a metal, but only above a certain frequency.

SL ●●●HL ●●●Simulation + Modelling

E.2 Quantum physics HL

Full guide

Counting radiation: does it follow an inverse square?

Move a source twice as far away and the count rate should fall by four. Check it with real counts.

SL ●●●HL ●●●Database + Modelling

E.3 Radioactive decay

Full guide

Shielding radiation: the absorption coefficient

Thicker shielding blocks more radiation. Find how the count falls and what the material tells you.

SL ●●●HL ●●●Database + Modelling

E.3 Radioactive decay

Full guide

Dice decay: does chance follow the exponential law?

Roll many dice and remove the sixes. The decay follows the same pattern as radioactivity.

SL ●●●HL ●●●Lab + Modelling

E.3 Radioactive decay

Full guide

Background counts: are they as random as they should be?

Radioactive decays are random, but randomness has a precise statistical shape.

SL ●●●HL ●●●Lab

E.3 Radioactive decay

Also works as an EE

Salt substitute: can you detect natural radioactivity in food?

A tiny fraction of potassium is radioactive. A shaker of salt substitute can be detected with a Geiger counter.

SL ●●●HL ●●●Lab

E.3 Radioactive decay

Also works as an EEFree full card

Rutherford scattering: can a simulation find the nucleus' size?

Alpha particles bounce off a tiny nucleus. Simulate the paths and compare with the famous law.

SL ●●●HL ●●●Simulation + Modelling

E.1 Structure of the atom

Also works as an EE

Hydrogen lines: can you pull out the Rydberg constant?

The colours of hydrogen follow a strict pattern. Fit it and extract one of physics' key constants.

SL ●●●HL ●●●Database + Modelling

E.1 Structure of the atom

Also works as an EE

Two ways to measure the expansion rate: why do they disagree?

The universe's expansion rate comes out different when measured from nearby supernovae and from the early cosmic microwave background.

SL ●●●HL ●●●Database + Modelling

E.5 Fusion and starsA.1 Kinematics

Listening to a black-hole merger: can you recover the masses?

The first gravitational wave rose in pitch as two black holes spiralled in. Its chirp encodes the masses.

SL ●●●HL ●●●Database + Modelling

D.1 Gravitational fieldsC.1 Simple harmonic motion

Numerical orbits: which integrator can you trust for 1,000 years?

Simple methods quietly gain or lose energy as a planet orbits. Measure how fast, and which methods avoid it.

SL ●●●HL ●●●Simulation + Modelling

D.1 Gravitational fieldsA.1 Kinematics

Do bigger stars really shine as M^3.5? Test it with binary stars.

Eclipsing binaries give the most accurate stellar masses and radii. Use them to test how luminosity scales with mass.

SL ●●●HL ●●●Database + Modelling

E.5 Fusion and starsB.2 Greenhouse effect

Can a liquid-drop formula predict how tightly nuclei bind?

A drop-of-liquid model of the nucleus predicts binding energies with five terms. Fit them to real nuclei.

SL ●●●HL ●●●Database + Modelling

E.3 Radioactive decayE.4 Fission

Muons from space: does their rate fall as cos squared of the angle?

Muons made in the upper air reach the ground only because of time dilation. Their direction dependence tests that physics.

SL ●●●HL ●●●Lab + Database + Modelling

A.5 Galilean and special relativity HLE.3 Radioactive decay

Quantum tunnelling: how does the leak depend on barrier width?

Particles pass through barriers that classical physics forbids. A simulation shows exactly how the chance falls with thickness.

SL ●●●HL ●●●Simulation + Modelling

E.2 Quantum physics HL

Sand patterns on a plate: what sets the mode frequencies?

Sand on a vibrating plate gathers along lines of no motion. Each pattern has its own frequency.

SL ●●●HL ●●●Lab + Modelling

C.4 Standing waves and resonanceC.3 Wave phenomena

Ripples on water: how do speed and wavelength depend?

Small ripples are driven by surface tension and large waves by gravity. There is a slowest wave in between.

SL ●●●HL ●●●Lab + Modelling

C.2 Wave modelC.3 Wave phenomena

Curving a ball: how does spin bend its path?

A spinning ball curves through the air. Measure how much deflection comes from how much spin.

SL ●●●HL ●●●Lab + Modelling

A.2 Forces and momentumA.1 Kinematics

Two linked pendulums: how does energy pass between them?

Link two pendulums by a spring and one swing slowly passes to the other and back.

SL ●●●HL ●●●Lab + Modelling

C.1 Simple harmonic motionC.4 Standing waves and resonance

Double pendulum: how fast do nearly identical swings drift apart?

A double pendulum is deterministic but chaotic. Measure how quickly tiny differences grow.

SL ●●●HL ●●●Lab + Simulation + Modelling

A.4 Rigid body mechanics HLC.1 Simple harmonic motion

Watching molecules push: can video give Boltzmann's constant?

Tiny particles in water jitter because molecules hit them. Measure the jitter and extract a fundamental constant.

SL ●●●HL ●●●Lab + Modelling

B.3 Gas lawsB.1 Thermal energy transfers

How much would doubling CO2 warm the Earth? Estimate it from data.

A simple one-box energy model and 70 years of temperature and CO2 records can estimate climate sensitivity.

SL ●●●HL ●●●Database + Modelling

B.2 Greenhouse effectB.1 Thermal energy transfers