[nudephil (OP)]

George sent us the following observation from the bird bath on his balcony:

As I fill up the bird bath with the garden hose and I push the hose nozzle closer to the bottom (to prevent spray), I notice that the hose suddenly gets drawn downwards when almost at the bottom.

My only thought was that the liquid "forces" created a negative pressure to "pull" the nozzle to the bottom... much like the differing air pressures on an aircraft wing.

Can anyone explain this phenomenon?

[chiralSPO]

Does it also work when the hose is off? (may as well also check with the bath full of water, as well as with it empty)

[Petrochemicals]

It can't be to close to the bottom can it? Surely the water column pressure would force the hose backward?

[Bored chemist]

I'd have a look at this
https://en.wikipedia.org/wiki/Bernoulli%27s_principle