IB Physics IA topics 2026: How to choose the right investigation for your grade
Strong IB Physics IA topics should produce reliable quantitative data, isolate a clear relationship between one independent and one dependent variable, and connect directly to a physics principle that can be analysed mathematically. Suitable investigations can come from mechanics, waves, electricity, thermodynamics, or electromagnetism, depending on the student’s interests and available equipment. The best topics are focused, experimentally feasible, and rich enough to support uncertainty analysis, graphing, and meaningful evaluation.
This guide explores effective IB Physics IA topic ideas and explains how students can turn a broad area of interest into a precise, measurable research question.
- What makes a strong IB Physics IA topic?
- IB Physics IA topic ideas from mechanics and motion
- IB Physics IA topic ideas from electricity and waves
- IB Physics IA topic ideas from thermodynamics and nuclear physics
- IB Physics IA topics to avoid and why they score poorly
- How to develop a focused research question from a broad IB Physics IA idea
- Frequently asked questions
What makes a strong IB Physics IA topic?
A strong IA topic satisfies three conditions simultaneously: It is experimentally feasible with standard school apparatus, it produces quantitative data with clear and measurable trends, and it connects directly to a specific physics principle covered in the IB syllabus.
One critical detail often overlooked is the relationship between your independent variable and your dependent variable. The IB marking rubric rewards investigations where this relationship is explicitly stated, testable, and physically justifiable. A vague topic like “investigating how heat affects electricity” will score poorly because neither the IV nor the DV is defined with enough precision to guide a rigorous experiment.
Strong IB Physics investigation ideas share the following characteristics:
- The IV is a single, continuously variable physical quantity (e.g., temperature in degrees Celsius, length in centimetres, tension in Newtons).
- The DV is measurable with a specific instrument that produces numerical values with associated uncertainties.
- All other variables can be realistically controlled or monitored within a school laboratory setting.
- The underlying physics can be expressed mathematically, allowing for graph linearization and analysis of gradients or intercepts.
Drawing on years of experience at Times Edu, we can state confidently that the single most common reason IAs score below a 6 is an insufficiently specific research question, not a lack of effort in writing up the final report.
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IB Physics IA topic ideas from mechanics and motion
Mechanics remains one of the most reliable areas for IA topic ideas in IB Physics [1], because the phenomena are visible, the apparatus is accessible, and the underlying physics is mathematically precise.
Terminal velocity of falling paper cones
This investigation asks how the cross-sectional area of a falling paper cone affects its terminal velocity. Students vary the cone diameter, drop cones from a fixed height, and use slow-motion video analysis (via a smartphone) to measure velocity over successive frames.
The physics focus sits firmly in fluid drag theory, specifically the relationship between drag force and cross-sectional area. This topic is particularly strong because it allows students to construct a mathematical model, test it against experimental data, and produce a log-log graph to linearize the power relationship.
Coefficient of restitution and temperature
This mechanics IA IB Physics topic investigates how the temperature of a sports ball, such as a squash or tennis ball, affects its coefficient of restitution. The student heats the ball to different temperatures, drops it from a fixed height, and measures the rebound height.
The underlying physics connects elastic and inelastic collisions to the thermal behaviour of gas inside the ball. Students who pursue this topic can reference ideal gas law reasoning to explain their results and produce clean, repeatable data using a ruler and a phone camera.
Damped pendulum and amplitude decay
Investigating how the surface area of a damping card attached to a pendulum affects the exponential decay of its swing amplitude is a particularly strong choice for HL students seeking depth. The physics of simple harmonic motion combined with logarithmic linearization of the amplitude-time graph provides rich material for the Analysis criterion.
Cantilever deflection and beam length
A wooden ruler clamped to a desk, with varying overhanging lengths and a constant mass suspended from the tip, generates deflection data that connects directly to Young’s Modulus and bending moment theory. This is one of the most accessible mechanics IA IB Physics topics in terms of apparatus, and it consistently rewards students who push into structural physics for their evaluation.
| Topic | IV | DV | Key Physics Principle |
|---|---|---|---|
| Paper cone terminal velocity | Cross-sectional area | Terminal velocity (m/s) | Fluid drag, free-body diagrams |
| Ball coefficient of restitution | Temperature (°C) | Rebound height (m) | Elastic collisions, gas pressure |
| Damped pendulum amplitude | Damping card area | Decay rate of amplitude | SHM, logarithmic linearization |
| Cantilever deflection | Overhanging length (cm) | Vertical deflection (mm) | Young’s Modulus, bending moments |
>>> Read more: IB Physics grade boundaries 2026: How they work and what they mean for your result
IB Physics IA topic ideas from electricity and waves
The electricity and waves strand offers some of the most sophisticated IA topic ideas for IB Physics SL and HL students, particularly for those comfortable with measurement instruments like oscilloscopes, multimeters, and data loggers.
Refractive index and fluid temperature
This investigation uses a laser pointer directed through a tank of sugar solution at varying temperatures, applying Snell’s law to calculate the refractive index at each temperature. The physics connects molecular density changes to wave speed in a medium, a topic that sits neatly within the Waves section of the IB syllabus.
In our experience working with international students, this topic consistently produces clean linear or polynomial relationships that are easy to model and evaluate. The main challenge is precise angle measurement, which itself becomes a productive source of uncertainty analysis.
Acoustic damping and material thickness
Students investigating how the thickness of a soundproofing material affects the decibel attenuation of a fixed-frequency sound source are working directly with wave absorption and intensity relationships. A sound level meter (available as a calibrated smartphone app or a standalone instrument) serves as the primary measurement tool.
This is a strong IA topic for students who are interested in acoustics or architecture and want to connect physics to a real-world context. The decibel scale introduces logarithmic reasoning, which adds analytical depth to the write-up.
String tension and fundamental frequency
Using a guitar string or a monochord apparatus, students vary the tension applied to a string and measure the fundamental resonant frequency using a microphone connected to a free spectrum analyzer application. The relationship is governed by the equation v = sqrt(T/mu), which allows for a linearized graph of frequency squared against tension.
This electricity and waves IA IB Physics topic is particularly well-suited for students with a musical background, as they bring intuitive understanding that strengthens the personal engagement and context sections of the report.
Electromagnetic induction and magnet speed
Dropping a neodymium magnet through a copper pipe and measuring the peak EMF induced in a coil wound around the pipe at different drop heights (which controls the magnet’s speed) tests Faraday’s law and Lenz’s law directly. This is an HL-appropriate topic that rewards students who can link eddy current braking to energy dissipation quantitatively.
A common mistake we see with this topic is failing to isolate a single IV. Students sometimes vary both drop height and coil number of turns in the same experiment, which violates the fundamental principle of a controlled investigation and collapses the analysis.
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IB Physics IA topic ideas from thermodynamics and nuclear physics
Thermodynamics IA IB Physics topics are often underutilised, yet they offer some of the cleanest quantitative data sets and the clearest links to first-principle physics laws.
Evaporative cooling and surface area
This investigation asks how the surface area of a water container affects the rate of thermal energy loss over a fixed time window. Students use containers of varying diameters, monitor temperature drop using a digital thermometer or thermocouple over 15-minute intervals, and model the results using Newton’s Law of Cooling.
The topic rewards students who understand the distinction between evaporative cooling, convective loss, and radiative loss, and who can evaluate which mechanism dominates under their experimental conditions.
Thermal conductivity of metals and rod length
Heating one end of a metal rod uniformly and recording the time for the opposite end to reach a target temperature across rods of different lengths generates data directly tied to Fourier’s Law of thermal conduction. This is one of the few thermodynamics IA IB Physics setups where the physics law itself provides an equation that can be tested graphically.
One critical detail often overlooked is the insulation of the rod’s lateral surface. Without it, heat loss through the sides introduces a systematic error that undermines the entire analysis. Students who identify and address this in their evaluation demonstrate exactly the kind of critical thinking that earns marks in the Evaluation criterion.
Solar panel temperature and efficiency
Investigating how the surface temperature of a photovoltaic cell affects its electrical power output under a constant light source connects semiconductor physics to practical energy generation. Students measure current and voltage output at different panel temperatures, calculate power using P = IV, and relate their findings to the behaviour of charge carriers in semiconductor materials.
This topic is particularly effective for HL students who want to demonstrate application of electrical concepts beyond the basic syllabus, and it generates strong real-world evaluation material around renewable energy.
| Topic | Physics Law | Recommended Level | Key Instrument |
|---|---|---|---|
| Evaporative cooling vs. Surface area | Newton’s Law of Cooling | SL and HL | Digital thermometer, data logger |
| Thermal conductivity vs. Rod length | Fourier’s Law | HL recommended | Thermocouple, stopwatch |
| Solar panel temperature vs. Efficiency | P = IV, semiconductor physics | HL | Multimeter, light source |
>>> Read more: IB Physics HL exam tips 2026: How to maximise your score across all papers
IB Physics IA topics to avoid and why they score poorly
Understanding which topics to avoid is as important as identifying strong ones. A number of overused IA topics in IB Physics are flagged repeatedly by IB examiners for lacking the depth required at this level.
The most commonly penalised topic is any variation of “how does the mass of a toy car affect its speed down a ramp?” This setup is mechanically straightforward, but it produces data with very limited scope for uncertainty analysis, graph linearization, or connection to advanced physics principles. It reads as a middle-school experiment conducted in an IB context, and examiners mark it accordingly.
“Measuring the speed of light using a microwave oven and chocolate” is another topic that sounds impressive in concept but fails in practice. The method is a classroom demonstration, not a controlled investigation. Precision is low, variables cannot be meaningfully isolated, and the write-up rarely achieves more than a surface-level treatment of wave physics.
Any experiment involving direct exposure to high-powered lasers without documented safety protocols, or high-voltage setups beyond the capacity of standard school equipment, should be avoided entirely. These introduce genuine safety risks and, practically speaking, are very difficult to manage within the data collection requirements of the IA.
The clearest signal of an overused IA topic in IB Physics is when the investigation produces only a handful of data points, offers no opportunity for a linearized graph, and has a predicted result that requires no physical reasoning to explain.
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How to develop a focused research question from a broad IB Physics IA idea
Many students arrive at the topic selection stage with a general interest, for example, “I want to do something with sound” or “I like the idea of investigating magnetism.” The process of converting that broad interest into a precise IB Physics IA research question follows a clear sequence.
Step 1: Identify the phenomenon. Start with a physical effect you find genuinely interesting. The more authentic your interest, the more naturally you will write about it.
Step 2: Identify the variables. Ask yourself: What single quantity can I change systematically? What single quantity will I measure as a result? Write these down explicitly before drafting any research question.
Step 3: Connect to a physics law or equation. Every strong IA research question points toward a specific equation. If you cannot identify the equation that governs your investigation, your topic is not yet specific enough.
Step 4: Check feasibility with available apparatus. Apparatus for IB Physics IA investigations does not need to be exotic. Digital scales, rulers, smartphones with slow-motion video, multimeters, thermometers, and signal generators are sufficient for many top-scoring IAs. The question is whether your proposed measurement is precise enough to yield meaningful data.
Step 5: Draft and refine the research question. A well-formed research question names the IV and DV explicitly. For example: “How does the overhanging length of a wooden ruler affect its vertical deflection when a constant mass is suspended from its tip?” Is far stronger than “How does the length of a ruler affect how much it bends?”
In our experience working with international students, Steps 2 and 3 are where the most time should be spent. A student who has clearly identified the physics law being tested will write a more coherent exploration and evaluation, even if their experimental execution has minor flaws.
>>> Read more: IB Physics common mistakes 2026: The errors that cost students the most marks
Frequently asked questions
What makes a good IB Physics IA topic?
A good IB Physics IA topic isolates a clear independent variable and dependent variable, connects directly to a measurable physics principle, produces quantitative data with sufficient range and precision for uncertainty analysis, and can be executed safely with standard school laboratory apparatus.
What are some strong IB Physics IA topic ideas for SL students?
SL students tend to produce their strongest results with topics like terminal velocity of falling cones, coefficient of restitution versus temperature, string tension versus fundamental frequency, and evaporative cooling versus surface area. These topics are accessible in terms of apparatus and produce data that can be analysed using SL-level mathematics.
What are some strong IB Physics IA topic ideas for HL students?
HL students should seek topics with a deeper mathematical structure. Recommended options include damped pendulum amplitude decay (requiring logarithmic linearization), electromagnetic induction and magnet speed, thermal conductivity of metals and rod length, and solar panel efficiency versus temperature. These topics allow HL students to engage with more advanced physical reasoning and graph analysis.
What apparatus do you typically need for an IB Physics IA investigation?
The apparatus for IB Physics IA investigations depends on the topic, but most strong investigations use instruments that are standard in a school laboratory. Common examples include digital calipers, electronic balances, thermometers or thermocouples, multimeters, signal generators, oscilloscopes, smartphones with slow-motion video or free spectrum analyser apps, and basic optical equipment like laser pointers and protractors.
What topics are overused in IB Physics IAs and should be avoided?
The most frequently penalised overused IA topics in IB Physics include toy car ramp experiments, microwave-and-chocolate speed-of-light demonstrations, and any investigation where the predicted result is trivially obvious without physical reasoning. These topics lack the depth needed to score well across the Personal Engagement, Exploration, Analysis, and Evaluation criteria.
How do you narrow a broad physics interest into a specific IA research question?
The key is to identify the specific physics law or equation that governs the relationship you want to test, then define a single independent variable that you can change in measurable increments and a single dependent variable that you can measure with a calibrated instrument. Specificity in the research question is the clearest predictor of a high-scoring IA.
Does your IB Physics IA topic need to involve quantitative experimental data?
Yes. The IB Physics IA is an experimental investigation, and quantitative data is a fundamental requirement. The Analysis criterion specifically rewards the processing of numerical data through graphs, uncertainty calculations, and mathematical modelling. An IA based solely on qualitative observations will not be able to achieve the marks available in Analysis or Evaluation, regardless of how well it is written.
Conclusion
Avoiding overused IA topics in IB Physics, selecting appropriate apparatus, and developing a focused IB Physics IA research question are skills that require guided practice, not just independent reading. At Times Edu, our specialist IB Physics tutors work with students one-on-one from the earliest stages of topic selection through to final submission, helping them build investigations that score well across every criterion while genuinely reflecting their own scientific curiosity.
If your child is entering the IA phase of their IB Physics course and you want to give them the strategic advantage of expert guidance from the very first step, we invite you to book a personalised academic roadmap consultation with our team today.
