Day 43 – F=mg

Physics 11 – In previous I my students always seem to have an on-going battle with “weight”, “force of gravity”, “Fg” and “mass.” I thought I’d confront this issue head on this year. My classes did a lab finding the relationship between Force of gravity and mass. They also used Excel to produce their graphs, which will make subsequent graphing tasks in class much faster. The students will then practice targeted questions on Fg. Hopefully this bit of time will pay off throughout the year.

Day 50: Force Diagrams and Balanced Forces


Physics 11 – I tried this problem with two blocks of physics 11.  The first block I had the students work individually and the second block they were put into random groups and did the problem on whiteboards.  As I’ve seen in other situations, the whiteboard groups had much more success. I don’t think it was a case of the strong student doing all the work – there was definite dialogue and sharing of ideas. However, the class ended soon after this question and I didn’t get the chance to do much formative assessment with individual students.

I love this question though, as it hits many topics covered in the past few days:

  • weight is the force of gravity
  • scales measure normal force
  • springs can support a surface, which exerts a normal force (equality of forces, reasoning)
  • you should draw a FBD when solving problems