Non-rotating Rayleigh-Benard Convection simulated with nek5000 (a spectral element code written by Paul Fischer at ANL). The aspect ratio (diameter to depth) is 1.0, the Rayleigh number is 5 *10^7, and the Prandtl number is 0.005 (representing Liquid Sodium). The velocity boundary conditions are no-slip on all walls and the temperature sidewalls are insulated. For this Prandtl number, the bulk of the fluid is tubulent, but the temperature is very diffuse and velocity is vigorous and finely filamented. This difference can be seen in the two movies, the first showing the temperature and the second showing the square of the vorticity.