Cornstarch Dimples
These photographs were taken every 0.9 s. Time increases from left to right and top to bottom. An initial hump on the rim begins growing upward resembling a finger. It reaches a maximum height and then topples outward, enlarging the area of the hole.
"There’s physics in my porridge!" said Goldilocks. Physicists at the University of Texas Center for Nonlinear Dynamics shook a bowl of cornstarch batter 80 times per second. When the scientists blew a dimple into the batter with a straw, it grew in to a deep hole. The vibrating hole then sprouted fingers as if it were alive! This phenomenon was observed to last for hours in repeated experiments at certain frequencies. The physics of vibrating fluids is a fascinating new area of research that is revealing many non intuitive results.
