IPhO Experimental Skills Problem Set (Official Papers + Write-Up Drills)
Curated IPhO experimental problems for training uncertainty, fitting, graphs, and clean evaluation under time pressure.
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This set is designed for one goal: stop losing experimental marks to presentation, uncertainty, and vague evaluation.
If you have not done the hub path yet, start with the IPhO Experimental Skills Hub.
Archive mirror index: https://phoxiv.org/contests/ipho
Official documentations page: https://www.ipho-new.org/documentations/
Read the framework once: IPhO Problem-Solving Framework
Do the hub Entry and Core lessons first (then return here):
Pick 1 paper section below and do it timed (then write a clean solution).
For evaluation, write 1 dominant systematic + direction of effect + 1 concrete fix.
Show the full hub lesson path (Experimental Skills | IPhO Prep)
Pick 1 Paper Section Per Week
Choose one E-problem section, do it timed, then write the solution as if the examiner is hostile (no missing units, no missing definitions, no hand-wavy evaluation).
- IPhO 2025 E1 — “Measurement of Earth’s magnetic field” (PDF)
- IPhO 2024 E1 — “Heat Conduction in a Copper Rod” (PDF)
- IPhO 2024 E2 — “Diffraction from Phase Steps” (PDF)
- IPhO 2023 E1 — “Mass Measurement” (PDF)
- IPhO 2023 E2 — “Birefringence” (PDF)
- IPhO 2022 E2 — “Cylindrical Diode” (PDF)
- IPhO 2021 E1 — “Non-ideal Capacitors” (PDF)
- IPhO 2021 E2 — “LEDs” (PDF)
- IPhO 2019 E1 — “Optical Measurements” (PDF)
- IPhO 2019 E2 — “Wiedemann-Franz Law” (PDF)
Write-up drill: the 8 lines that should appear in every solution
- “We aim to plot Y against X so Y = mX + c.” 2. “The gradient equals ___ (units) therefore the parameter is ___.” 3. “Uncertainty in measured quantities: ___.” 4. “Error bars shown for ___.” 5. “Gradient uncertainty estimated by ___.” 6. “Parameter value: p = (… ± …) with units.”
- “Result agrees/does not agree with theory within uncertainty.” 8. “Dominant systematic: ___ (direction of effect: increases/decreases the result). Fix: ___.”
Evaluation drill: stop writing 'human error'
Replace “human error” with named mechanisms:
- alignment error (parallax, off-axis measurement)
- drift (temperature, battery voltage, ambient light)
- calibration/offset (zero error, scale factor)
- contact resistance / lead resistance
- heat loss / non-adiabatic conditions
For each, state the direction of effect and a realistic control (reversal, calibration, shielding, insulation, baseline subtraction, longer timing, etc.).
Write your final answer in the format: parameter ± uncertainty (units), then 1 sentence on agreement, then 2 sentences on evaluation.