Physics: Kirchoff’s Rules Revisited

Since the last quiz over Kirchoff’s Rules didn’t go as well as I’d hoped, we took some time to revisit the concepts and try a few more problems. Students left a lot more comfortable. They also really responded to an analogy I got from Kelly O’Shea thinking of current as people flowing through a hallway. It was pretty easy to get them to see that adding a new route in the halls made it easier to get around, which helped them get that adding a parallel branch actually reduces the resistance.

Chemistry: Parts Per Million

Today, students did some calculations using parts per million as a measure of concentration. They were pretty surprised at how small a number you get when you convert ppm into a percent concentration by mass, along with the fact that those low concentrations are really pretty significant in their impacts.