Experience videos

Some physics experiments performed in the department are presented here.

Baroclinic instability on a turntable

On our planet, the temperature difference between the poles and the equator generates a circulation in the atmosphere, which is then modified by the rotation of the Earth (Coriolis force) to generate strong winds blowing from west to east at mid-latitudes (jet streams). This circulation will then destabilize, giving rise to eddies that correspond to the alternation of cyclones (low pressure, disturbed weather) and anticyclones (high pressure, stable weather). These eddies allow heat to be transported efficiently from the equator to the poles.

Such dynamics can be reproduced on a laboratory scale in a rotating cylindrical tank, the cold region of the poles being simulated by a box filled with ice water placed in the center of the tank, and the hot region of the equator by a hair dryer blowing on the edge of the tank. With the help of dyes, we can then materialize the destabilization of the azimuthal jet, and the formation of local vortices, more numerous the faster we rotate, which correspond to the high and low-pressure regions mentioned above.