Wednesday, October 07, 2009

The importance of units

Some educators believe that kids learn through repetition.  Others believe that too much repetition will turn the kids off from the learning.  Both can cite evidence that support their view.

The truth is probably in between.  Some kids do learn from repetition.  But once they master a subject, drilling them further would annoy them and cause them to make more mistakes.  I don't even think the same kids respond to the same treatment in different subjects or on different days.  Heck, I know that my annoyance level and attention to detail vary from day to day.

Wow, that was a long introduction.

Anyway, in 4th and 5th grade, my daughter's teachers allow the kids to test out of math units.  In 4th grade, if the kids passed the pretest with 85% or more, they didn't have to do the homework or take the final unit test.  They were allowed to select from some other math enrichment activities.  This year, in 5th grade, her teacher allows the kids to test out of homework.

She came home very upset last night, with 17 out of 23 possible points on her math test.  Her errors?  She lost 1/2 a point for every time she didn't label her units or wrote down the answer in an incomplete equation.  She did all the calculations right.

She was looking for sympathy.

She got none.

I wouldn't tolerate an incomplete equation any more than I would tolerate an incomplete sentence.  That is is ok for casual conversation (or blogging), but not ok for a test.

Bad Dad and I were in perfect agreement about units.  She is too young to remember the loss of the Mars orbiter because one team used metric units and the other used English units.  It never occurred to them to check with one another because they assumed the rest of the world operated the way they themselves did.  That engineers still use English units was a complete shocker for me; scientists use metric.  So perhaps the notion didn't occur to the NASA scientists either.

(The link failed to mention that the software that failed was written by a complete newbie engineer without guidance or supervision from a more experience engineer.  Or that the software did not conform to software standards such as containing a header containing all parameters and constants used and their units, but that's a whole 'nother story.)

So she will have to do drill and kill this week until labeling the units is as natural as breathing.

I didn't tell her that mommy was the scary TA that took points off lab reports for each spelling and grammatical error.  If your language lacks attention to detail, will people have faith in your calculations?


  1. I shared the math/Mars orbiter story with my son, who is also a homework hater but a total stickler for grammatical and mathematical accuracy. He agreed with you and Bad dad. They should have done THEIR homework at NASA. Good for you for making her dot the i's etc.

  2. We went to Berkeley, where engineering and physics majors take the same lower division physics sequence. This means that engineering majors use metric units in lower division and English units in upper division courses and that they understand that different communities of practice use different units.

    Science majors at Cal (and evidently many other places) don't learn that.

    The danger is that engineering students at many other school don't learn that the majority of the world uses metric units. Science is international. If the kid was working on a science mission for NASA, he should have known enough to check in with others about units. That he didn't, and he never labeled his units, meant that it never occurred to him that others wouldn't be using the same units he did. He obviously didn't go to Cal.

    Was he improperly trained or a terribly incurious student? That he was left alone to work on this software module with no supervision is unforgivable.

    When industry technical managers complain about the 'ivory tower' background and lack of 'real world' experience of engineers from first tier schools like Cal, I try not to get angry.

  3. Good for you! I had to learn a similar lesson in 6th grade (mine was more to do with reading instructions and not hurrying through classwork just because it is "easy" and boring...) and I still think it is one of the most important things I learned in grade school. My parents backed the teacher, too.

  4. Good for you. I lost points for failing to dot my i's and cross my t's. I was the scary "TA" who took off points for history essays with poor spelling and grammar (although you wouldn't know that from my blog). Except I was the professor's high-school age daughter. That was how I earned spending money.


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