IB Physics IA ideas: 300 investigations, sorted by syllabus topic

Pick an idea where you can measure the dependent variable precisely with equipment your school already has, then change the research question until it is yours: a different material, a wider range, or a model you test at the point where it should break. 33% of the ideas here need only basic lab kit.

Forces and momentum has the most ideas (52), because friction, drag and collisions are easy to measure. 40 ideas use HL-only physics, such as rotational mechanics, induction and quantum physics, and are marked as HL topics. Every idea opens to show the variables, the graph to plot, how far to take it at SL and HL, and the design mistakes that cost marks.

8 investigations appear on four or more of the 7 lists, and 87% of the ideas appear on only one. The overdone ones are safe to run but hard to make stand out, because examiners have marked them many times.

• Launch angle and range with a calibrated launcheron 5 lists · A.1
• Falling-sphere viscosity of honey across temperatureon 5 lists · A.2
• Acceleration against sin θ on a friction-affected rampon 4 lists · A.2
• Temperature coefficient of resistance of a metal wireon 4 lists · B.5
• Refractive index of sugar solutions as a concentration probeon 4 lists · C.3
• Testing Malus's law with a rotating analyser and a light sensoron 4 lists · C.3
• Resonance lengths in a closed tube and the end correctionon 4 lists · C.4
• Absorption of β and γ radiation by aluminium and leadon 4 lists · E.3

These ideas need only basic equipment, suit SL and HL, and appear on one public list at most, so an examiner is less likely to have seen them. There is one for each topic page where such an idea exists.

• Launch angle and range of a golf ball from a putter or wedge

  How does the launch angle θ (10°, 20°, 30°, 40°, 50°, 60°, 70°) of a golf ball fired by a spring or pendulum launcher affect its horizontal range, in m, when launched from the same height?

• Apparent weight loss in liquids and Archimedes' principle

  How does the upthrust on a fully submerged 100 g brass cylinder change with liquid density from 800 kg m⁻³ to 1250 kg m⁻³ using five liquids or salt solutions?

• Ball speed at the foot of a ramp against release height

  How does the release height, varied from 5 cm to 30 cm in 5 cm steps, affect the speed of a steel ball at the bottom of a 1.0 m ramp, and what fraction of gravitational potential energy becomes translational kinetic energy?

• Cooling constant of water in cups of different surface area

  How does the open top area A of a beaker (A = 20 to 80 cm², five sizes) filled with 150 g of water at 80 °C affect the cooling constant k over 20 minutes?

• Solar cell output power against tilt angle under a lamp

  How does the maximum power output of a small silicon solar cell vary with tilt angle θ from 0° to 80° in 10° steps, under a lamp fixed 0.30 m from the cell centre?

• Capacitor charging voltage against energy released

  How does the charging voltage of a 4700 μF capacitor (2 to 12 V in 2 V steps) affect the energy delivered as it lifts a small mass?

• Does bob mass change pendulum period? A precision test

  Does the period of a simple pendulum of length 0.80 m released from 10 degrees change when the bob mass is varied from 20 g to 200 g in six steps?

• Slinky pulse speed and a length that should not matter

  How does the speed of a longitudinal pulse on a metal Slinky change as it is stretched from 2.0 m to 5.0 m, and is the travel time really independent of length as the wave model predicts?

• Resonance lengths of a closed air column and the end correction

  How does the first resonant length L of an air column closed at one end, made with a tuning fork or a speaker tone, vary with driving frequency f from 256 Hz to 1024 Hz in 6 steps, and what end correction does this give for a tube of 30 mm internal diameter?

• Testing Kepler's third law with moons of Jupiter

  Does the period squared against orbital radius cubed for the four Galilean moons follow a straight line, and what mass of Jupiter, in kg, results?

• Estimating the Hubble constant from a galaxy catalogue

  What value of the Hubble constant, in km s⁻¹ Mpc⁻¹, follows from a linear fit of recession speed against distance for 20 to 30 galaxies within 300 Mpc?

The IA is one investigation of at most 3000 words, marked out of 24 with four criteria of 6 marks each: Research design, Data analysis, Conclusion and Evaluation. It is 20% of the final grade at SL and HL, and the 2025 guide dropped the separate marks for personal engagement and communication.

In practice that moves the marks towards the method. A design that controls the variables that really matter, enough data to see a trend and its uncertainty, and a conclusion that compares a measured constant with the accepted value score more than an original topic executed loosely. That is why each idea here names its controlled variables and the graph to plot.

378 ideas were collected from 7 public lists: six tutoring sites and a collection of published student IA titles. Ideas with the same independent and dependent variable were merged, keeping count of how many lists carry each one, and every entry was rewritten from scratch and reviewed. A few ideas are my own and appear on no list.

No text from the original lists is reproduced: an automatic check compares every entry with the sources and finds no run of eight words in common. Topics follow the IB Physics guide for first assessment in 2025. The full list is available as JSON. This is independent work, not endorsed by the International Baccalaureate. Last updated 26 September 2026. Corrections: pietro@pietromeloni.com.