Ferro Fluid

In this exhibit, we rotated the disc to move the magnet attached to it and we observed the black fluid on the pan.
The black fluid is Ferro fluid. This liquid is a colloidal mixture of small magnetic particles suspended in a liquid carrier. Ferrofluid becomes strongly polarized in the presence of a magnetic field. When the magnet is moved out of the pan, ferrofluid is dragged up to the side of the container.