Jezza and Clive live their lives by the old Scottish saying, “Never have whisky without water, nor water without whisky!”
Clive settles down for his evening whisky, which he pours out in front of him. Jezza has the same-sized glass of water.
Clive takes a spoonful of his whisky and pours it into Jezza’s water, who then stirs it into his drink before and places a spoonful of the resulting mixture back into Clive’s drink. Jezza claims this means they have the same amount to drink.
The question is, is there more whisky in Jezza’s water, or more water in Clive’s water?
Hint: We have not said how large the spoon is.
Consider for a moment that the spoon is as large as the glass itself. In this case, the spoonful would entail mixing all total liquids, and assuming they’re well-mixed, there would be pretty much half water and whisky in each glass.
If we dive a bit deeper, let’s say each glass contains 100ml of whisky and water, respectively. Transferring one to the other doesn’t alter the concentration of either liquid. Once the liquid is transferred, each glass still has 100ml.
The whisky displaces the water one for one, there is the same volume of whisky in one glass as there is water in the other, regardless of how well the mixtures were mixed.
