Resistivity vs Temperature: Four-Wire Lab Skills for H2 Physics
Study guide
Reviewed by
Chee Wei Jie·Academic Advisor (Physics)
Q: What does Resistivity vs Temperature: Four-Wire Lab Skills for H2 Physics cover?
A: Use a Kelvin bridge setup, thermocouples, and spreadsheet linearisation to map how conductor resistivity changes with temperature.
TL;DR
Build a four-wire (Kelvin) measurement rig with a constant-current source, thermocouple probe, and Logger Pro or Google Sheets to capture resistance as a function of temperature.
Linearise the data to extract temperature coefficients for copper, nichrome, and graphite, then discuss systematic errors like self-heating and thermal gradients.
The experiment deepens Paper 4 understanding of resistive materials and gives you a real dataset for planning-style questions on resistivity control.
Why This Lab Merits a Slot in Your Practical Calendar
- It extends the familiar internal-resistance experiment into material science, matching examiner emphasis on real-world instrumentation.
- Students practise proper four-wire techniques that appear in university physics and engineering labs - a valuable talking point for UCAS and admissions essays.
- The investigation integrates thermal physics, circuits, and error analysis, reinforcing multiple chapters of the 9478 syllabus at once.
Apparatus and Instrumentation
| Item | Notes |
| Four-wire test jig with Kelvin clips | Eliminates lead resistance so your slope reflects the sample only. |
| Constant-current source (0 - 1 A) | Keeps current stable as resistance changes, limiting self-heating. |
| Sample rods (copper, aluminium, nichrome, carbon) | Length 10 - 15 cm, diameter logged for cross-sectional area calculations. |
| Thermocouple with digital reader (±0.1 °C) | Tape firmly to the sample to capture core temperature. |