Recently, I was in a discussion (about Evolution vs Intelligent Design) and I made a point with an illustration, namely, how difficult it is to measure very small things without changing them.
The illustration that I used is one I read somewhere, but I have no idea where. If we want to measure the temperature of a body of water, we can stick a thermometer in it. That's fine for large bodies of water but what about small ones? Stick a thermometer into a drop of water, and the temperature of the thermometer will change the temperature of the drop of water, thus rendering your measurement worthless. I called this an example of the Heisenberg Uncertainty Principle because that's what the person I had read years ago called it.
My opponent simply replied, "No it's not." To double-check myself, I checked Wikipedia, and I see the true definition only regards particles, namely, we can't know their both their position and their momentum with precision, and the more precise we measure one, the less precise the other becomes. I think my illustration was what is commonly called the Observer Effect, but now I'm not sure.
So with my puddle illustration, am I all wet?