Is our current introduction of the mole counterintuitive?

So once again, I stare into the blank eyes of a student who is wondering how can the mole tell us mass and number. For a minute lets take the view of the students. When I write up the number 602,000,000,000,000,000,000,000 up on the board, it looks to them as if I just pulled that out of my ass. We really need to start with the relationship between mass and particles. This starts with an introduction of how we came to that weird number. We should introduce it in a way that makes it see valuable. Perhaps we need to have them try weighing grains of salt in one gram of salt. this would show them the same concept. In my calculations, there are 6,679 grains of iodized salt per gram. This would allow them to relate something very small to the large numbers required to describe it. Ultimately, we chose 6.02×10^23 so we wouldn’t have to add another value for each element on the periodic table. We just wanted to rate the relative atomic masses to relative masses in grams. The mole is just a lazy unit so we don’t have to write out obscenely large numbers all the time. I think it’s about time for our students to appreciate how it makes ours and their lives easier. What do you think?


2 thoughts on “Is our current introduction of the mole counterintuitive?

  1. I completely agree, and I think the same applies to molar mass. The Modeling curriculum does a nice job of drawing the connections between Avogadro’s principle and relative masses of the elements by having students play around with the idea of “counting” by weighing, which seems like the example that you have using salt. I think the key here is presenting in a way that makes it “valuable” (since a student’s view of what is valuable may be much different than a chemist’s) but in a way that is similar to how it was originally calculated by scientists.

    I do agree that it is a “lazy” unit, but at the same time provides a critical connection between the atomic and macro levels of matter, which is what chemistry is all about!

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