Thermal physics
Conduction, convection, thermal radiation
Compare the three heat-transfer mechanisms — conduction, convection, radiation — and verify Fourier's law for a sample bar. Vary the temperature difference ΔT and conductivity k to measure the transferred power.
Equipment
- Canvas model of the three mechanisms (conduction through a bar, convection loop, radiation rays)
- Temperature-difference slider ΔT (5–80 K)
- Thermal-conductivity slider k (10–400 W/m·K)
- Sample bar A = 0.01 m², L = 0.50 m; readout
Procedure
Distinguish the three mechanisms
Watch the canvas: conduction carries energy through stationary matter along the bar, convection moves heat with the flowing fluid, and radiation travels as electromagnetic waves needing no medium. Drag to rotate and compare how heat travels in each.
Measure conducted power
Keep k = 200 W/m·K (a typical metal) and set ΔT = 10 K: the readout gives W. Double ΔT and check that P doubles — the linear Fourier relation.
Compare conductors and insulators
Lower k from 400 to 10 W/m·K (metal → ceramic/foam) at fixed ΔT: the conducted power falls proportionally — insulators are low-k materials. Raise ΔT to a high value and predict P before reading the result.