An experimental study has been made of heat transfer from a flat plate with nominally uniform surface heat flux aligned parallel to laminar flows of Newtonian and shear thinning liquids, for a range of plate Reynolds numbers (30-2000) and fluid Prandtl numbers (50-400). Finite element solutions of the coupled flow and conjugate heat transfer problem have been obtained, using a recent form of the SUPG formulation for isoparametric biquadratic finite elements, extended to take account of variable physical properties. Close agreement with experimental plate surface temperatures provides confidence in both our experimental and numerical techniques.