I smiled knowingly as I read the “In My Opinion” article by M. P. Jones and Courtney J. Cook regarding the SI-gap in the November 2017 TPT.1 At the beginning of each course I taught during 36 years in secondary physics and chemistry classrooms, I worked very hard to convince students that U.S. customary units were not worth using, and made discussing and analyzing measurements more challenging than they need to be. From about 1975 on, the first investigation my students completed involved making numerous measurements using only SI units. This resulted in the students “owning” a reference for 1 gram (a small paper clip), 1 milliliter (one handful of water is about 7 ml), 1 kilometer (the distance to the first bridge when turning right out of the school driveway), and 1 newton (the weight of 100 small paper clips).

After a brief introduction to using the...

Supplementary Material

AAPT members receive access to The Physics Teacher and the American Journal of Physics as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.