October 14: Gravity HW review

Alexis observed class today. The goal was to spend 10-15 minutes going over the homework problem and then to start into the light reflection lab. What actually happened was, since the students were very confused about the homework, nearly all of the time was spent covering how to use a calculator and a little time was spent on units. Despite taking up so much time, I felt that I did a good job of organizing the discussion and getting the points across. Alexis’ review was largely favorable as well. A lot of confusion had to do with calculator usage, order of operations, and units. 

I explained the scientific notation button (x10n), negative button (+/-), and square button (x^2) by drawing a table. In the table I wrote down the desired function, the different ways it shows up for various calculators, how it should be entered, and an example to try. For units I just showed how they cancel out, mentioned that forces are measured in Newtons, and stressed that if you know what you are calculating, you can check yourself by making sure the units of your answer are correct. I also mentioned a simplified rule for rounding (truncating your answer to have the same number of digits as your inputs). 

At the end of class, two more problems were assigned. Essentially the same thing, but with different masses and distances. Two pages on light were assigned for reading.