Going through some old files, I found a homework assignment that my younger daughter did seven or eight years ago. When doing RDF-related data modeling you put a lot of thought into properties, and I remember getting a kick out of this introduction to the concept when she brought it home.
The smiley face shows that on a later page she did well on the worksheet that evaluated how well she understood this. By now, I think she would understand datatype vs. object properties if she was interested, but so far she's not.
The second page, not shown here, is titled "Properties Can Change," a topic that continues to vex data modelers. In my own future data modeling, in addition to asking myself things like "is there a popular subproperty of rdfs:label that I should be using here?" I will also make a point of asking myself "Is it hard as a rock or as soft as a dream?"
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