At one point while setting up a charging station, a student found a controller smoking. He didn't know what to do and was obviously distressed. We were afraid that the controller might have been damaged. I told him to disconnect the battery, to cut of power to the controller. I waited a bit for the controller to cool down. There did not seem to be serious physical damage. I suspected that he might have accidentally reversed the polarity of the cables attached to the battery, causing a high current to flow through the controller. So I told him to connect the cables again to see whether the controller can still function, making sure that the polarities are correct. It worked! The controller seemed OK. He was so relieved. I proceeded to explain to him what has happened, what he could do when such things happen, and why.
This is what we call a teachable moment. This is why service-learning can be so effective as a pedagogy. You are faced with a real world problem where your actions have real impact. The student is motivated to do a job that is obviously meaningful. If it is done well, your client is deeply appreciative. If you fail, it can also be hugely disappointing for everyone. He is completely focused and eager to do it right. When he makes a mistake, he is under pressure to learn how to fix it. When he does fix it, he is so totally relieved and satisfied. I am sure this moment will stick in his mind for the rest of his life. This is also one of the most rewarding moments for a teacher.