When I taught history and anthropology, I would begin a semester by showing my students a stick. The students show their ideas of what the stick can be turned into. I then explain the stick never changed, but our thoughts of it did.

We go through a few slides of things that are different depending on how you think about them. Guns, swords, cultural objects, and others are discussed.

It's a great way to explain perspective and thought to students. Now I realize many of the female students didn't get it.