The fluid only needs to be heated gently. Heating or cooling a section of a fluid generally results in a change in density, which causes that section of the fluid to rise or fall.
Rheoscopic fluid makes the flow pattern visible.
The fluid can be poured into a plastic box, and a vial of ice can be floated on top of the room-temperature fluid, setting up convection currents. Similarly, a weighted vial of hot water can be placed on the bottom of the box. The fluid comes with a manual from Novostar Designs, detailing how the fluid can be used to model ocean currents, coastal erosion, aerodynamics, and can be used to show convection. There is also a convection activities kit.