An unusually long day


I got up early today, because I was giving a new lecture today, and while I got most of it done last night, I was plumb wore out then and told myself I’d finish it in the morning…which I did. Then I had to give the lecture, and immediately afterwards run over to the hospital for an echocardiogram.

This was routine, my doctor just wanted to check that I have a heart, or that it kinda sorta works. I do, and it does, but there was a little accident. They put in an intravenous line so they could inject me with some kind of contrast agent, and when they punched in, it sprayed out — a little jet of blood splattering me, the bed, and the doctor (sorry, doc). It was much messier than it needed to be, and made everything a bit splatterific. I didn’t mind, but it was just that kind of day.

Then I had to teach a lab for a few hours: this lab was all math, basic unit conversions, volume calculations, etc. Most of our bio students aren’t comfortable with calculations and managed to twist their brains around multiple times, so I had to explain why yeast cells probably don’t have a volume measured in liters and how a lake a kilometer across probably has more than 100 microorganisms floating in it.

Now I’m all wrung out, and am counting the minutes to bedtime.

Comments

  1. billseymour says

    Pleasant dreams (or dreamless if that make waking up more pleasant for you).

    I got an IV today as well.  I’m running out of veins, but they found one on the back of my hand which worked.  My chemo doctor has switched me to immunotherapy, just one half-hour drip every three weeks.

    I also had another test of cognitive decline that’s part of a study that I’m participating in and probably similar to the one that Trump misremembered.  I think I did OK, but then I guess I wouldn’t really know if I didn’t. 8-)

  2. whheydt says

    How did your students make it out of high school without getting a grip on units and unit conversions? Dunno why I should be surprised though. I was an EECS major and we probably had to deal with more types of units than your freshmen do.

    As for IVs…years ago my late wife and I were regular blood donors, so no fear of needles. Since then…enough time in hospitals for one thing or another, and the frequent blood tests that goes with age and condition, I sometimes wonder why they don’t just put in a permanent tap…

    Contrast dye… Been there, done that. Most recently was last Spring after my cardiologist suddenly realized that my bypasses are 24 years old, and they’re only expected to be for about 12 years. (Turns out they’re in fine shape…much to the surprise of all the doctors involved.)

  3. markp8703 says

    “I had to explain why yeast cells probably don’t have a volume measured in liters and how a lake a kilometer across probably has more than 100 microorganisms floating in it.”

    Years ago, my better half was teaching second year marine biology undergraduates about Stokes’ Law (in this case estimating the speed of diatoms etc. falling through sea water.) She was marking the work at home and ran a couple of answers by me. One had them falling at a fifth of the speed of light, another at three times the speed of light.

    I’ve never understood why people don’t think about units and don’t double check their work if there’s a result that seems counter-intuitive.

  4. Bekenstein Bound says

    Or, at the very least, at least think “three times the speed of light? I’d better redo this in a relativistic rather than a Newtonian framework”. :)

  5. birgerjohansson says

    It’s cool to like Dexter, but don’t overdo the LARPing; you get blood all over.
    BTW if you want to keep up with the eternal election campaign it is easiest to just watch Seth Meyers Stephen Colbert or Jimmy Kimmel. That way even bad news get palatable.

  6. whywhywhy says

    Education: not just going through the steps but asking the question ‘Does this answer make sense?’ and having sufficient understanding to be able to answer the question.

  7. Robbo says

    three times the speed of light?

    if the student had only converted the answer to more familiar units, it would have been obvious the answer made no sense.

    three times the speed of light is 5.4×10^12 furlongs per fortnight.

    obviously not a possible speed for a diatom, even one with a jetpack.

  8. says

    You do realise, don’t you, that “unit conversions” are simply Not A Thing in most of the world?

    You simply measure every length in metres, no matter how absurd this might feel at first; every mass in kilograms, every time in seconds, every area in square metres, every density in ⁻kg.m⁻³ and so forth; and then rely on exponential notation to keep the numbers manageable. (In the days of slide rules and log tables, you really didn’t have any choice but to use exponential notation.) Keep separate track of the units and simplify where appropriate. (For instance, kg.m².s⁻¹ is the same as N.)

    When your answer is ready, assuming the units don’t have any powers higher than 1 in them, all you need do is normalise the exponent not in the pure mathematicians’ way so there is one non-zero digit before the point, but in the engineers’ way, so the exponent is a multiple of three. It will then conveniently match up with a prefix; for instance, if the exponent is +6, that’s mega-somethings.

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