Some time ago, I wrote about not being able to find my car in the university parking lot (If It'd Been a Snake, It Would've Bit Me):

Often, I wonder, Why don't my students get it? Why don't they see what I see? Perhaps it's because they're not looking where I am.

Trimmer SpoolOn Saturday, I was reminded how knowing where to look depends on one's experience. I was trying to reload my electric lawn trimmer with new nylon string. The manual had a picture that gave the basics but apparently not the "fine" points that I needed because when I tried to insert the spool back into the head, it didn't fit: The string was crossing an edge and stopping it from being inserted. After 15 minutes of re-reading the manual, looking at the images, scratching my head, and trying again and again, I gave up. Time to go back to the store.

At the store, the salesman showed me how to thread the nylon string. I had missed the grooves for the nylon string to lie in so that the string wouldn't be outside the edge of the spool. Note that the spool image doesn't show any grooves, either. And he showed me a few other tips to ensure that it would work right.

All of this reminds me of the importance of examples for learning. After he showed me, it all made sense, but before his example, I simply didn't see what was in front of my eyes. Of course, I can imagine that eventually I would have figured it out, but one good example can save hours of figuring things out.

It also reminds me that without practice, what is learned is forgotten. The same salesman had shown me how to thread the spool a year ago, but I had not practiced once since then.

I'm just lucky that I'm not overlooking a snake.