I like the examples that you give your students using specific heat. I agree that since the math behind specific heat problems is easy that if you only focus on the math, the students completely miss the concept. Another example I use is similiar to your "attention getter." I talk to them about when they are cooking spagetti or macaroni and cheese after a few minutes heating a pot of water, they would burn their hand on the pot but the water may only feel luke warm.
There is one other problem I like to give the students. I tell them about two folding chairs that I put outside in the sun. One of them is made of iron and the other out of aluminum. After giving them the specific heats of each of the metals, I ask them which one would be hotter to sit in.
I didn't find any technical problems with this lesson.