Thrift with attitude

We had an interesting performance from the shampoo this morning, when draining the last of the old bottle into the new bottle. Otherwise a lesson in the dynamics of viscous liquids with a tendency to form bubbles.

It is taking quite some time for the process to complete, something between one and two hours for the spoonful of shampoo to move from top bottle to bottom bottle.

A process which involves one lot of bubbles emerging up from the passage and forming on the surface inside the top bottle. And another lot of bubbles emerging down from the passage, through the 5mm nozzle, drifting down the sides of the neck of the bottom bottle and eventually merging with the surface below. The nozzle from the bottom bottle having been removed, as nozzle to nozzle balancing is hard. But it can be seen bottom right.

The bubbles start as spheres and have a tendency to form hexagons where they meet, I suppose because a hexagon is the nearest polygon that can pack to a circle.

The actual flow of shampoo appears to be down the joins between the faces of the bubbles.

Exercise for reader: if there was a lot of shampoo in the top bottle and enough space in the bottom bottle, would you eventually get a thread of shampoo emerging directly from the nozzle down onto the surface of the shampoo in the bottom bottle, without touching the sides?

Then would it be a stream or would it be a succession of drops? My recollection of this sort of thing with runny honey is that you start off with big drops, which gradually shrink down into a continuous thread. And when it has shrunk enough, the thread stops being continuous and goes back to drops. Evidence, I might say, of a porridge filled childhood.

PS: 1021: we have now reached a point where we have a layer of fairly uniform bubbles, maybe 10mm across, covering the neck and shoulders of the top bottle. Is this a close to equilibrium state which will take a while to resolve to vacuity?

PPS: 1317: bubbles still there, of square appearance from the side, hexagonal viewed from the top, so cylindrical bubbles. But most of the shampoo left in the top bottle looks to have drained down the joins to the shoulders and will eventually make its way downstairs. What then for the bubbles?

PPPS: 1530: bubbles still there, but those in the middle are sinking and getting smaller. Only a matter of time before the keystone bubble (as it were) at the centre gives way.

PPPPS: 2045: experiment terminated with the top layer of bubbles still holding in there; sunken but intact. Bottom bottle too full for a natural ending.