|MadSci Network: Chemistry|
Milk contains many 'ingredients'. Of course there is fat (non in 'non-fat' milk), but there are also proteins in milk. These proteins are floating around in your milk, which is a colloidal system.
When you add lemon juice (or vinager), the water in which the proteins are floating becomes acidic and the proteins don't like this. They start to 'flock' together, because if they are curdled they have less surface which is in contact with the acidic water.
The same proces, but not with lemon juice, is used when making cheese.
About the second question, well as far as I know it does happen, but only wehn both sinks are placed completely horizontal and are perfectly shaped. I forgot (stupid) the explanation.
Editor's Note: Please see the file in our archives that discusses vortices: 833396752.Ph
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