[libraryofbabel]

To turn that on its head, it's a wonderful teaching moment to ask a room full of smart students to try and prove (or even convincingly argue) that the Earth moves around the sun. A great way to get people to examine their assumptions and look afresh at the world around them.

As you say, it is indeed very hard to do, which is a good part of the reason why even when Copernicus published his heliocentric model (not a proof, but a new mathematical model) his ideas took decades to become mainstream. If you have a rudimentary telescope / binoculars and know to look, then you can observe that Venus has phases and use that as a basis for argument (as Galileo did), but even then, it's perfectly possible to cook up special models where Venus has phases and the earth is still stationary (see https://en.m.wikipedia.org/wiki/Tychonic_system).