The Ultimate Guide to the IB Physics IA: 50+ Topic Ideas & Pro Tips

Hey there! Let's talk about the IB Physics Internal Assessment, or as it's now officially called, the "Scientific Investigation". This is your chance to be a real physicist—designing an experiment, collecting data, and analyzing it all on your own. It's a big part of your final grade (worth 24 marks!), and honestly, choosing a great topic is half the battle won.

This guide is designed to walk you through everything, from understanding the new 2025 assessment criteria to brainstorming a topic that's both interesting and high-scoring. Let's dive in.

First Things First: Understanding the New (2025) Assessment Criteria

Before you even think about topics, you need to know what the examiners are looking for. The game has changed for exams from May 2025 onwards! The old rubric is out, and a new, streamlined set of four criteria is in. Each is worth 6 marks.

1. Research Design (6 marks)

This is your blueprint. Can you create a focused, relevant research question? Is your methodology clear, detailed, and reproducible? You need to outline your variables (independent, dependent, and controlled), list your apparatus, and address any safety or ethical concerns.

2. Data Analysis (6 marks)

This is where you show your work. It's all about how you record, process, and present your data. This means clear tables, correctly annotated graphs (with error bars!), proper use of significant figures, and a thorough treatment of uncertainties. You need to interpret the trends your data reveals.

3. Conclusion (6 marks)

Did you answer your research question? Your conclusion must be a direct response, supported entirely by the evidence from your data analysis. You need to connect your findings back to the underlying physics principles and scientific theory.

4. Evaluation (6 marks)

Time to be critical. This is about reflecting on your investigation. What were the strengths of your method? What were the specific weaknesses and limitations? Most importantly, how did these weaknesses impact your data, and what are some realistic, meaningful improvements or extensions for the future?

What about Personal Engagement? While it's no longer a separate criterion, your personal interest and initiative are still vital. This is now demonstrated through the other criteria—in the originality of your research question, the care in your methodology, and the depth of your analysis.

How to Choose Your IA Topic: A Strategic Framework

A good topic is a balance between what interests you and what's practical. Don't just pick the first thing you see online. Think like a physicist.

Key Considerations for a Winning Topic:

Personal Interest: Seriously, pick something you find cool. You'll be spending a lot of time on this. If you love sports, music, or even video games, try to find the physics in it.
Feasibility: Can you actually do this experiment with the equipment in your school lab? Avoid anything that needs a particle accelerator. Keep it simple enough to be completed well within the 10-hour timeframe. A simple idea executed perfectly beats a complex one done poorly.
Clear, Measurable Variables: Your experiment must have one thing you can change (the independent variable) and one thing you can measure as a result (the dependent variable). Both must be quantifiable. "Type of material" is a weak independent variable; "thickness of material in mm" is a strong one.
Strong Link to Physics Theory: Your investigation must allow you to discuss and apply concepts from the IB Physics syllabus.

The "How does X affect Y?" Brainstorming Method

This is the most reliable way to frame a research question. Think about a cause-and-effect relationship you can test.

Example Independent Variables (X - What you change)	Example Dependent Variables (Y - What you measure)
Angle, Height, Mass, Distance, Temperature, Current, Voltage, Length, Concentration, Pressure	Time, Velocity, Acceleration, Force, Period, Frequency, Resistance, Power Output, Refractive Index, Rebound Height

Crafting the Perfect Research Question

Once you have an idea, you need to turn it into a focused research question. It's the compass for your entire investigation. Stick to this format:

"How does the [Independent Variable (X)] affect the [Dependent Variable (Y)] of a [Specific system or context]?"

Example of a great research question: "How does the temperature of a tennis ball affect its coefficient of restitution when dropped from a constant height?"

The Inspiration List: 50+ IB Physics IA Ideas

Stuck for ideas? Use this list as a starting point. Remember to add your own personal twist to make your investigation unique. Always check with your teacher to ensure your idea is feasible.

Mechanics

How does the launch angle of a projectile affect its horizontal range?
How does the cross-sectional area of a falling coffee filter affect its terminal velocity?
How does the angle of an inclined plane affect the acceleration of a rolling object?
Investigating the relationship between the period of a simple pendulum and its length.
How does the mass suspended from a spring affect its period of oscillation?
How does the internal pressure of a basketball affect its rebound height?
Investigating how the centripetal force on a rotating object is affected by its angular velocity.
Determining the coefficient of static friction between two surfaces with varying normal force.

Thermal Physics

How does the surface area to volume ratio of a container affect the cooling rate of hot water?
Investigating how the thickness of an insulating material affects the rate of heat loss.
How does the salinity (salt concentration) of water affect its specific heat capacity?
How does the temperature of a liquid (e.g., motor oil) affect its viscosity?
Verifying Charles's Law: How does the temperature of a gas affect its volume at constant pressure?
How does the color of a surface affect its rate of thermal energy absorption?

Waves & Oscillations

How does the tension in a guitar string affect the frequency of the sound it produces?
Investigating the relationship between the length of a closed air column and its resonant frequency.
How does the depth of water in a tray affect the speed of surface waves?
How does the concentration of sugar in a solution affect its refractive index?
Determining the wavelength of a laser using a diffraction grating.
Investigating Malus's Law: How does the angle between two polarizing filters affect the intensity of transmitted light?

Electricity & Magnetism

How does the length of a nichrome wire affect its electrical resistance?
How does the temperature of a conductor affect its resistance?
Investigating how the number of coils in a solenoid affects the strength of its magnetic field.
How does the temperature of a battery affect its internal resistance?
How does the distance from a light source affect the voltage output of a solar cell?
Investigating the time constant of a discharging RC circuit by varying the resistance.
How does the speed of a falling magnet through a coil affect the magnitude of the induced EMF?

Modern & Quantum Physics

Investigating the inverse square law for gamma radiation using a G-M counter.
How does the thickness of a shielding material (e.g., aluminum foil) affect the absorption of beta radiation?
Determining Planck's constant using the turn-on voltage of different colored LEDs. (A classic but solid choice).

Level Up: Unique IA Ideas to Show Personal Engagement

Want to stand out? Try adding a unique variable or combining different areas of physics. This is where you can really show your creativity.

The Magnus Effect: How does the spin rate of a ball affect its trajectory? (Combines Mechanics & Rotational Dynamics).
Damped Oscillations: How does the viscosity of a liquid (e.g., water, oil, glycerine) affect the damping of an oscillating pendulum? (Combines Mechanics & Fluid Dynamics).
Sports Science: How does the temperature of a squash ball affect its coefficient of restitution? (Combines Mechanics & Thermal Physics).
Musical Physics: How does the humidity of the air affect the speed of sound, measured using resonance in a tube? (Combines Waves & Thermal Properties).
Material Science: How does temperature affect the Young's Modulus of a plastic ruler? (Combines Mechanics & Thermal Physics).

The Lanterna Tip: A simple experiment done with meticulous care, deep analysis, and thoughtful evaluation will always score higher than a complex, "impressive" experiment that is poorly executed. The goal is to demonstrate your skills as a physicist, not to discover a new law of the universe. Chat with your teacher, pick something that genuinely interests you, and get started!

A strong, focused research question is the foundation of a top-scoring Physics IA. It should be specific, measurable, and clearly link an independent variable to a dependent variable (e.g., "How does the temperature of a tennis ball affect its coefficient of restitution?"). A great question makes the methodology, analysis, and conclusion much clearer to write.

The new syllabus (from May 2025) streamlines the assessment into four, equally weighted criteria: Research Design, Data Analysis, Conclusion, and Evaluation. The separate "Personal Engagement" criterion has been removed, but its spirit is now integrated into how you justify your choices and demonstrate curiosity throughout the report.

Common pitfalls include choosing a topic that's too broad or simple, not collecting enough data (aim for at least 5 increments of your independent variable, with 5 trials each), overlooking uncertainties in measurements, and writing a weak evaluation that just suggests "using better equipment." A critical reflection on methodology is key.

Our tutors, who are all expert IB graduates, can help at every stage. They can help you brainstorm a feasible and engaging topic, refine your research question, design a robust methodology, and critically analyse your data. They are masters of the IB criteria and can guide you on structuring your report to hit top marks, while always respecting academic honesty policies.

The Evaluation is where many students lose marks. It requires a deep, critical look at your experiment's limitations and their impact on your conclusion. If you're struggling, a Lanterna tutor can help you identify specific weaknesses and suggest meaningful improvements or extensions. A free consultation with a Student Success Expert is a great first step to see how we can help.

Our IB consultation is a free, 20-30 minute online call for IB students and their parents with one of our Student Success Experts. It's designed for anyone feeling overwhelmed by the IA, struggling with a specific part of the IB, or simply wanting a strategic plan to boost their grades and confidence.

Yes, completely free. There is absolutely no obligation to purchase tutoring afterwards. The goal of the call is to provide genuine value by helping you identify challenges, set clear priorities, and understand the next steps needed to succeed in the IB. You will leave the call with a clear action plan.

Our Student Success Experts are specialists in the IB programme. They have extensive experience guiding families through the demands of the Diploma. During your free consultation, they listen to your specific needs—whether it's for the Physics IA or overall IB strategy—and help build a personalised plan to help you achieve your goals with less stress.

You'll receive a summary of your discussion and the clear, actionable plan you created. You can use this plan to guide your own studies. If you feel that one-on-one support from a top IB graduate tutor would be helpful, the Student Success Expert can also explain how our tutoring works and match you with the perfect tutor for your needs.

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