# Conceptual and unit problems with 'weight_kg' variable in Episode 1#938

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opened this issue Jun 21, 2021 · 2 comments
Open

# Conceptual and unit problems with 'weight_kg' variable in Episode 1 #938

opened this issue Jun 21, 2021 · 2 comments
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type:discussion Discussion or feedback about the lesson

### ellenkeister commented Jun 21, 2021

 During my teaching demo, I noticed an issue that the trainer running the demo session suggested I mention as an issue for my checkout contribution. It's a small thing, but most of the programming intro sessions (including https://swcarpentry.github.io/python-novice-inflammation/01-intro/index.html) start with a variable for the weight of a patient in kilograms. I am a former physics professor, and I am compelled to note that the kilogram is a unit of mass, not weight. While this may seem nit picky, we spend a great deal of time in intro physics teaching students the important differences between mass and weight, which is actually a force. While it is unlikely that the use of 'weight_kg' in a Software Carpentries lesson is going to significantly increase physics students' existing incorrect intuition and conflation of weight and mass, perhaps this could be changed to something like height in meters vs inches. This would be consistent with the lesson story about inflammation in patients, as well as the unit conversation examples and application. I'm not sure the best way to "correct" this concept-unit inaccuracy in all of the Carpentries lessons that have it, but this is the lesson that I am most familiar with, so I started here. The text was updated successfully, but these errors were encountered:
added the type:discussion Discussion or feedback about the lesson label Jun 22, 2021

### namurphy commented Jun 23, 2021

 Thank you for raising this issue! I've usually changed this example to something like `distance_in_kilometers` and `distance_in_miles` in sessions with lots of physicists, primarily because the distinction between mass and weight can distract away from the flow of the lesson.

### maxim-belkin commented Jul 2, 2021

 Thanks for bringing this up, @ellenkeister, and for your comment, @namurphy. As a physicist myself, I saw this discrepancy too. It is, however, so common that not only I don't worry about it, I'd be surprised if anyone ever answers to the "How much do you weigh?" question with "I weigh 800 Newtons". But, of course, we (maintainers of this lesson) would be happy to review a PR that addresses this issue.