Re: Why does water stay in the ocean but not in an upside down tea cup?

Hi Matthew and Mom

The key to this answer is that "up" and "down" are not consistent directions. I am writing 
this answer from a country where the direction of "up" is at 5 o'clock to your SouthWest 
(counting "up" where you are as 12 o'clock). I have a cup of tea beside my computer, 
which is upside down in your directions, and I can assure you that the tea is staying in 
the cup perfectly well! 

I also spend my whole life walking around "upside down", though it does not seem like 
it to me.

The answer is really to do with gravity. Centrifugal force does not come into it except in 
the tiniest way (less than 1%). Gravity does not pull in a single direction, but it pulls 
towards the centre of the earth. Where I am, the centre of the earth is in a very different 
direction from what it is where you are.

(We even speak a slightly different language -- I should have started with 
"G'day Matthew and Mum" ;-)