Abstract
The natural convection in a horizontal particle layer underlying a fluid layer was observed. Polystyrene beads were used for the particle layer, which were laid in a tank filled with water. Convection pattern was visualized by the use of the microcapsule of the thermosensitivity liquid crystal and food dye. The fluid layer showed unsteady convection pattern. In the particle layer, two patterns of convection were observed. One was a convection of steady flow and linear in vertical distribution of temperature, the other was concentrated upward flow and curvilinear in vertical distribution of temperature.
