Originally Posted by PraedSt

Heh. I can do the Observer effect. The act of observing X, changes X. It's quite a general statement, in the sense that you can apply it in many fields, not just physics. Psychology and economics for example.

So thermometer/water. As you said- if there is enough water, this effect (heat transfer from water to thermometer fluid, or vice versa) is negligible. With a drop of water, it's not. Observing the temperature of the drop, will significantly changed it's temperature.