Physics IA ideas: how do you choose one?
Choose an idea that fits the subject criteria and can be answered with evidence, a method, and resources you can access.
A strong Physics IA question produces data you can linearise: choose variables so that a graph of the processed quantities gives a straight line whose gradient or intercept is a physical constant. Mechanics, circuits, oscillations, and thermal questions all lend themselves to this.
Which research questions fit Physics IA?
The questions below are starting points to adapt to your own variables, evidence, and assessment task.
How does the length of a simple pendulum (0.10–1.00 m) affect its period, and what value of g does the gradient of T² against L give?
- Difficulty:
- easy
- Time:
- 1 week
- Equipment:
- basic
- Analysis:
- T² vs L → extract g
- Feasibility:
- 5/5
- Overused:
- Often seen
- Biggest trap:
- Amplitude too large
Variables · IV: string length. DV: period from 20 oscillations. Control: bob mass, release angle (<10°), same timer.
Note · Classic but strong if the uncertainty analysis on g is thorough.
How does the drop height affect the coefficient of restitution of a bouncing ball, and is it constant?
- Difficulty:
- medium
- Time:
- 1 week
- Equipment:
- school lab
- Analysis:
- Linearised spring graph
- Feasibility:
- 5/5
- Overused:
- Often seen
- Biggest trap:
- Spring permanently deformed
Variables · IV: drop height. DV: rebound height (slow-motion video). Control: ball, surface, temperature, same frame rate.
How does the length of a current-carrying wire in a magnetic field affect the force on it, measured on an electronic balance?
- Difficulty:
- medium
- Time:
- 1 week
- Equipment:
- school lab
- Analysis:
- V vs I gradient
- Feasibility:
- 4/5
- Overused:
- Often seen
- Biggest trap:
- Wire heating changes resistance
Variables · IV: wire length in the field. DV: force = g × Δmass reading. Control: current, magnet arrangement, wire orientation.
Note · Gradient gives the magnetic flux density B of the magnets.
How does the angle of an inclined plane affect the acceleration of a trolley down it, and what does extrapolation predict for 90°?
- Difficulty:
- hard
- Time:
- multi-week
- Equipment:
- specialized
- Analysis:
- log graph for exponential
- Feasibility:
- 3/5
- Overused:
- Less common
- Biggest trap:
- Background radiation not subtracted
Variables · IV: incline angle. DV: acceleration from light gates or video tracking. Control: trolley mass, track, release point.
How does the temperature of a thermistor affect its resistance, and how well does the data fit an exponential model?
- Difficulty:
- easy
- Time:
- 1 day
- Equipment:
- basic
- Analysis:
- Projectile range vs angle
- Feasibility:
- 5/5
- Overused:
- Often seen
- Biggest trap:
- Release height inconsistent
Variables · IV: water-bath temperature. DV: resistance from a multimeter. Control: measuring current (low), probe contact, settling time.
Note · Plot ln R against 1/T to test the model and extract the material constant.
How does the mass added to a vertical spring affect its oscillation period, and what spring constant does T² against m give?
- Difficulty:
- medium
- Time:
- 1 week
- Equipment:
- school lab
- Analysis:
- Resonance curve
- Feasibility:
- 4/5
- Overused:
- Less common
- Biggest trap:
- Damping from nearby surfaces
Variables · IV: hanging mass. DV: period from 20 oscillations. Control: same spring, small amplitude, no swinging.
How does the depth of water affect the speed of a surface wave in a ripple tank or long tray?
- Difficulty:
- medium
- Time:
- 1 week
- Equipment:
- school lab
- Analysis:
- Snell's law gradient → n
- Feasibility:
- 4/5
- Overused:
- Often seen
- Biggest trap:
- Ray not thin enough
Variables · IV: water depth. DV: wave speed = distance/time from video. Control: tray, pulse generation method, temperature.
How does the number of turns on a homemade electromagnet affect the mass of paperclips it can hold?
- Difficulty:
- hard
- Time:
- multi-week
- Equipment:
- specialized
- Analysis:
- Min/max slope uncertainty
- Feasibility:
- 2/5
- Overused:
- Less common
- Biggest trap:
- Friction not characterised
Variables · IV: coil turns. DV: maximum mass lifted. Control: current, core, battery freshness, paperclip type.
Note · Monitor current with an ammeter - internal resistance change is a real systematic effect to discuss.
How does the length of a wire affect its resistance, and what resistivity does the gradient give?
- Difficulty:
- easy
- Time:
- 1 week
- Equipment:
- basic
- Analysis:
- Hooke's law limit
- Feasibility:
- 5/5
- Overused:
- Often seen
- Biggest trap:
- Extension beyond elastic limit
Variables · IV: wire length. DV: resistance from a four-point or V/I measurement. Control: wire gauge, temperature, contact pressure.
How does the surface area of a parachute affect the terminal velocity of a falling model?
- Difficulty:
- medium
- Time:
- 1 week
- Equipment:
- school lab
- Analysis:
- Power vs voltage squared
- Feasibility:
- 3/5
- Overused:
- Less common
- Biggest trap:
- Ammeter loading error
Variables · IV: canopy area. DV: terminal velocity from video tracking. Control: payload mass, drop height, canopy material.
How does the initial temperature difference affect the rate of cooling of water in a beaker, and does it follow Newton's law of cooling?
- Difficulty:
- easy
- Time:
- 1 day
- Equipment:
- basic
- Analysis:
- g from free-fall
- Feasibility:
- 5/5
- Overused:
- Often seen
- Biggest trap:
- Human reaction time on timer
Variables · IV: starting temperature. DV: cooling-rate constant from an exponential fit. Control: beaker, volume, room temperature, surface exposure.
How does the distance between a solar cell and a lamp affect the cell's output power, and does it follow an inverse-square relationship?
- Difficulty:
- medium
- Time:
- 1 week
- Equipment:
- school lab
- Analysis:
- Stefan-Boltzmann log plot
- Feasibility:
- 2/5
- Overused:
- Less common
- Biggest trap:
- Bulb temperature not measured directly
Variables · IV: lamp distance. DV: P = VI across a fixed load. Control: lamp, load resistance, ambient light, cell angle.
Find questions that fit your resources
Filter the Physics ideas by time and equipment. This is a practical shortlist, not a judgement about the quality of a research question.
12 of 12 starting points match these time/equipment filters
- 01How does the length of a simple pendulum (0.10–1.00 m) affect its period, and what value of g does the gradient of T² against L give?
- 02How does the drop height affect the coefficient of restitution of a bouncing ball, and is it constant?
- 03How does the length of a current-carrying wire in a magnetic field affect the force on it, measured on an electronic balance?
- 04How does the angle of an inclined plane affect the acceleration of a trolley down it, and what does extrapolation predict for 90°?
- 05How does the temperature of a thermistor affect its resistance, and how well does the data fit an exponential model?
- 06How does the mass added to a vertical spring affect its oscillation period, and what spring constant does T² against m give?
- 07How does the depth of water affect the speed of a surface wave in a ripple tank or long tray?
- 08How does the number of turns on a homemade electromagnet affect the mass of paperclips it can hold?
- 09How does the length of a wire affect its resistance, and what resistivity does the gradient give?
- 10How does the surface area of a parachute affect the terminal velocity of a falling model?
- 11How does the initial temperature difference affect the rate of cooling of water in a beaker, and does it follow Newton's law of cooling?
- 12How does the distance between a solar cell and a lamp affect the cell's output power, and does it follow an inverse-square relationship?
Items with unspecified equipment or time remain visible. Check safety, ethics, available evidence and the current assessment guide before choosing.
Research question feasibility test →Sources & verification
Primary-source references used to verify key assessment facts on this page. Last source check: September 22, 2026.
These Physics ideas are original iBacalao starting points, not official IB research questions. Check the current Physics subject guide, your assessment session and your school's safety/ethics rules before committing to a question.
- IB: Diploma Programme assessment and examsOfficial overview of criterion-related assessment and internal assessment in the Diploma Programme.
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