Exhibit: Orb

Spin the orb around and watch as the fluid mimics a planet’s atmosphere. The layer of liquid between two plastic domes contains small, shiny, flat crystals of mica, which reveal the flow lines when the liquid moves. If you spin the dome, you see flow patterns reminiscent of the movement seen in the atmosphere of Jupiter. When you turn the dome, the fluid in contact with the plastic walls is dragged around. This layer then drags around the layer of fluid next to it and so on. The fluid at the bottom (by the equator) goes round the largest circle, so moves fastest. As it speeds up, there is a sudden change from steady flow to turbulent flow which begins at the equator and spreads upwards, towards the pole.