12 IB Physics IA ideas

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.