How to Choose a Winning IB Physics IA Topic (With 15 Practical Examples)

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Choosing a winning IB Physics Internal Assessment (IA) topic comes down to striking a balance between personal engagement, clear physical principles, and feasibility in a school laboratory. A high-scoring IA does not require groundbreaking physics; it requires a well-scoped investigation with precise variable control, low systematic uncertainty, and rigorous error analysis.

Key Criteria for a Top-Mark IB Physics IA

Simple Setup, High Rigor: The experimental apparatus should be easy to construct, allowing you to focus your effort on collecting precise data and conducting thorough error propagation.
Continuous Variables: Ensure both your independent and dependent variables are quantitative and continuous (e.g., measuring length vs. period, or temperature vs. viscosity).
Controlled Environment: Select topics where external factors like air currents, ambient temperature, or stray friction can be minimized or accounted for mathematically.
Relevance to Syllabus: Your research question must directly link to IB Physics concepts (e.g., SHM, fluid dynamics, electromagnetism, thermal physics, or wave mechanics).

15 Practical IB Physics IA Topic Ideas

Mechanics & Simple Harmonic Motion (SHM)

Damped Pendulum Motion: Investigating how the surface area of an attached drag card affects the damping coefficient of a simple pendulum.
Bifilar Pendulum: Analyzing the relationship between the distance between two suspension strings and the period of torsional oscillation.
Restitution of Balls: Examining how temperature affects the coefficient of restitution ($e$) of a squash or tennis ball dropped from a fixed height.
Terminal Velocity in Viscous Liquids: Investigating how the diameter of a steel sphere affects its terminal velocity in glycerol or engine oil.
Cantilever Deflection: Determining the relationship between the overhang length of a uniform ruler and its static vertical deflection under a fixed mass.

Waves & Acoustics

Speed of Sound in Gases: Measuring how ambient temperature affects the speed of sound inside a resonance tube using a signal generator.
Reflective Refraction / Water Depth: Investigating how water depth affects the phase speed of surface ripple waves produced by a mechanical oscillator.
Refractive Index & Temperature: Examining how the refractive index of a sugar-water solution changes as a function of solute concentration using a laser pointer.

Thermal Physics & Thermodynamics

Cooling Rates & Surface Area: Investigating how the surface-area-to-volume ratio of a container impacts the rate of convective heat loss of water.
Thermal Conductivity of Metals: Measuring the temperature gradient along rods of different metals to determine their relative thermal conductivity coefficients.
Stefan-Boltzmann Law Approximation: Examining how the power output of a filament lamp scales with temperature (calculated via resistance).

Electromagnetism & Circuits

Internal Resistance of Batteries: Investigating how battery temperature impacts its internal resistance ($r$) under a constant load.
Magnetic Field Strength of Solenoids: Measuring how the turn density of a custom solenoid affects the magnetic flux density at its center using a Hall probe.
Electromagnetic Induction & Fall Speed: Investigating how the terminal velocity of a neodymium magnet falling through a copper pipe varies with pipe wall thickness.

Fluid Dynamics & Modern Physics

Magnus Effect on Rotating Cylinders: Examining how the rotational speed of a cylinder affects the lateral lift force generated in a uniform airflow.

Step-by-Step Scoring Checklist

Research Question: Must state the independent variable, dependent variable, and controlled conditions explicitly in one sentence.
Data Collection: Aim for at least 5 distinct values for your independent variable, with 5 trials per value to calculate standard deviation and random error.
Uncertainty Analysis: Include both absolute and percentage uncertainties for all instrument readings, and propagate them through your final calculated values using error propagation formulas.