Comment by MengerSponge

The problem you run into is that laypeople operate with modified Aristotelian physics. They might "know" that the speed of light is a speed limit, and they might "know" that quantum mechanics says you can't measure anything.

They also believe that objects keep moving after you push them because they retain a memory of your push, and when that force runs out the objects come to rest*

You are not, will not, cannot teach them how to do a meaningful modern calculation in a single conversation**. Hell, Feynman's lectures were a failure: they didn't serve the audience he was supposed to be teaching (first year students).

So are you talking to students? Or is this a cocktail conversation? Because those are two very different settings.

*&**) These points are extensively documented in the PER literature. SciComm is really important and really useful, but it's not the same as effective pedagogy.