Heat a fluid from below and the warmed part expands, becomes less dense, and floats upward. Cooler, denser fluid sinks to take its place, and a circulating convection current forms. Put the heater at the top instead and the warm fluid simply stays up there, so nothing circulates. Predict the motion, then switch the heater on.
MissionPredict what the warm fluid does, then run the heater.Streak 0Best 0
With the heater at the bottom, the warm fluid will:
heater positionbottom
resulta circulating current
warm fluid is less dense, so it rises; cool fluid sinks to replace it.