I let my kids practice with hammers, nails and wood (tools / supplies) before I introduce building a piece of furniture (the educational end-goal). These models are the tools of the trade.
I agree with the sentiment that if work is messy, teaching should have messy as well. But not when you're starting out with new tools.
+1 for the kids tools. To extend, I let my kids practice hammering first, then sawing, then some other skill. Learning to work with messy data can wait until you are used to the new tools.
I agree with the sentiment that if work is messy, teaching should have messy as well. But not when you're starting out with new tools.