Hi All, I think David has it right.
When I put a hose into my swimming pool (a very large bucket) the effect is barely noticable - probably caused only by local eddies. When it is put into a small bucket with the same nozzle it becomes pronounced. With no nozzle the effect is *greatly* diminished in the bucket (but it is still there). I'll have to try it with a hose with the end cleanly cut off - a hose with no bluff. I think I have some in the garage somewhere... I might have a few different sized buckets to try too... The temperature will be in the mid to high 90's (35+ c) here today. This will be a good excuse to stop working for a while and go for a swim! On Sundials - A while back on the cover of Science News Magazine there was a sundial in the shape of a boat in a pond. The sail of the boat provided the style/gnomon. When water was in the pond the shadow was refracted to a different hour line than when the pond was dry. I don't remember what this 'correction' was used for. Has anyone used refraction of light in in water for casting shadows in this way? Chuck O'Connell Massachusetts, USA Message text written by David Higgon > >For simplicity, consider the hose vertical and aligned to the centre of the >bucket. This will set up a flow that goes down the middle of the bucket, >radial out when it gets to the bottom, up the sides and radially back in to >the middle at the top (roughly speaking). When the hose is inserted into >the middle, it is basically being put into a liquid that is flowing >vertically down - what is happening in the rest of the bucket I believe is >relatively incidental. >
