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My kingdom for a tutor (not Tudor)! February 24, 2017

Posted by mareserinitatis in career, education, physics, science, teaching.
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I’ve been very quiet.  There’s good reason for that: prepping for new classes is a lot of work.

Specifically, I’m teaching university physics for the first time, and I have to admit that it’s very different from the other side of the (hypothetical and totally non-existent) podium.  I’m also doing it as a flipped class, which is adding an extra layer of challenge as finding good videos is a particularly large time-suck.  (No, it’s not faster than writing my own notes…but it does seem to be more effective.)  Part of the reason it’s taking so much time is that I am spending a lot of time trying to figure out exactly where my students are at.  I can definitely tell that this is a struggle for the ones who haven’t had much calc before, which is a feeling I certainly can understand as I was in the same boat when I started college.  Unfortunately, we don’t have enough tutors who can handle physics to help everyone since our enrollment is way up. Not yet, anyway.

I am loathe to assume that someone who has insufficient math is not necessarily capable of passing physics.  (After all, almost everyone I know says that you learn as much calc in physics as you do in an actual calculus class, a viewpoint which has a certain amount of merit.)  As a result, I told students who didn’t do so well on the first test that I expected them to see me for weekly appointments.  (Note: I did not *require* them to…just said I expected it.  Not sure they understood the difference, but I figured it wasn’t worth explaining as most of them showed up.)  I think they weren’t too excited about it at first, but the ones who are showing up are doing so very regularly.  Apparently word got around, though, and even students who seem to be doing fairly well have started showing up, too.  My office hours have basically turned into giant study sessions.  (I think I need to start bringing donuts.)  I had half the class show up over a two day period for the latest homework.

I personally think this is good.  I am getting a sense for the kinds of things they have difficulty with and the overall frustration level has been decreasing, at least among the students coming in for help.  In particular, getting some help with reasoning and processes is more effective when it’s coming from someone who has been doing this stuff for a long time.  I’m tickled when they come in and automatically start doing the stuff I’ve been drilling them on (‘draw your free body diagram and then sum your forces!’) without any prompting.  I also never realized how much homeschooling my kids would come in handy: when you’ve supervised all grade levels of math, you end up picking up lots of handy tricks to make life easier.  I’m now able to pass those tidbits on to my students to help remedy some of the common computational issues I’ve run into.

I did tell them, however, that they better be prepared: next year, I will be teaching more classes, so they need to sign up to tutor the incoming freshman.  A couple of them laughed.  I don’t think they realized that I’m serious.

A New Semester January 17, 2017

Posted by mareserinitatis in education, physics, teaching.
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I’m teaching physics this semester, and I have to admit that I’m in a slight panic.  At most places, physics is a 4 to 5 credit class.  It’s only 3 credits here, and I have a pretty strict schedule on what I need to get covered.  I can do it, as long as I don’t get off track, but it’s daunting.

The down side is that sometimes students don’t realize right away that they will be taking the class, so they miss the first couple days.  In my case, that means a week.

I’m doing something different in terms of homework, though, to compensate for how quickly we’re moving.  The students are getting a “mini” homework assignment each class.  Part of me knows this is going to be a pain because grading is generally one of my least favorite part of teaching.  (I think that’s true of most people I know, so I don’t feel terribly ashamed about it.)  The class is also “big,” which means the grading is going to take me longer than I had hoped.  I wasn’t sure if this was a good idea until I went through the first homework.

One of my late additions very clearly didn’t know what was going on.  I saw this was a problem and so I suggested he come see me so I could go over the information he missed.  This afternoon, I stepped him through my notes.  Things were rocking along and then he got that look on his face: it was like a giant light bulb went off.  He stopped, his mouth came open and his eyes seemed to pop out.  Then, after a few seconds, there was that slight smart to a smile.

Oh.  NOW I get it.

I really love that expression, and I think he’s happier because I gave him the opportunity to redo it now that he actually understands what we’re doing.

Conversations with the kid February 25, 2016

Posted by mareserinitatis in physics, science, Uncategorized, younger son.
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Younger son: “I don’t care if Tesla was smarter than you, I still love you.”

Me: “But he was only just a bit smarter, right?”

Younger son: “Nope.  He was a lot smarter.  You just do physics.”

Me: “I also do electrical engineering.”

Younger son: “Oh.”  *wanders off to kitchen*

Thanks for the vote of confidence, kid.

Biased for science December 10, 2014

Posted by mareserinitatis in feminism, geophysics, math, physics, science, societal commentary.
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I’ve taken a couple tests at Project Implicit.  The premise is that we have unconscious biases that may unknowingly affect decisions we make about other people.  I remembered this after coming across an article on race from the Washington Post.  I’d taken a test before that said I had a bias against blacks.  I’m owning up to it, but now that I’m aware of it, I try to recognize it’s there when making decisions.

I revisited the site to see if I could retake the test and if my results had changed, but I was distracted by the shiny things.  In particular, I saw there was a test on the subconscious preference to associate science with male and liberal arts with female.  Given the studies about how labs hire women less often and there is a subtle bias in salary, as well, I thought, “this could be interesting.”

And it was.  I was expecting to show a rather strong relationship between men and science.  Not only is that the most common association, but it seems like working in a male-dominated field would make that a no-brainer.

Iat-gender-science

Your data suggest a moderate association of Female with Science and Male with Liberal Arts…

I’m one of the 3% who took the test who has that association.  If what I read in the Washington Post article applies to this study, most of the people taking this test are younger, more liberal, and more female than the average population, so the test may actually mean that the 10% who associate females with science is actually an overestimate.

Why do I have that association, particularly working in the field I do?  (I feel a bullet list coming on.)

Some potential ideas:

  • Being a female scientist is a very strong part of my identity, so I would naturally equate the two.  While at first guess, I would think this would be a no-brainer, the studies I cited above seem to indicate that’s not the case for most women scientists.
  • I have a lot of female friends that are also scientists.  As an undergrad, I was the only female physics major, but I made friends with a lot of female math, engineering, and physics and math education majors.  In my MS program, I spent a lot of time with other women engineering students, the handful I could find.  Going to a grad program (in earth sciences) means I was in a program with near gender-parity among the students.  Through the beauty of the internet, I’ve also made friends with other women scientists.  I think I’m likely to “see” more women in science than the average person…or even the average scientist.  “Women in science” isn’t a token female here or there but an actual sizable demographic in my world.  I think that this sort of exposure has probably had the most profound effect on my biases.
  • I know a lot of men who are interested in liberal arts.  Probably the most strongly influential one is older son, who is very much into drawing and writing.  I spend a lot of time with him, so that also probably affects my perceptions.

I’m curious how others fare on this test as well as their analysis of their own results.

Extra-dimensional conversations October 13, 2014

Posted by mareserinitatis in physics, science, younger son.
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The younger son occasionally has band lessons after school.  Recently, I picked him up and he said that his band teacher hadn’t been in her office when he was supposed to have his lesson.  The next comment surprised me.

You know, in an alternative universe, I forgot my instrument but she was in her office.  And then there’s other universes where I had my instrument and she was in her office and others where I forgot my instrument AND she wasn’t in the office.

Apparently he has combinatorics licked.

I was somewhat surprised at this response, so I asked him what he knew about other universes.

Not much.  I just know you use wormholes to get between them.

I responded that wormholes are supposed to transport you across time and space, but wasn’t sure if the strict physics definition allowed for travel outside of our universe.

Mom, wormholes transport you across dimensions!

This made me wonder if he knew about M-theory.  When I asked him what he knew about higher dimensions, he said,

Well, they’re really similar.  But after a short time, you notice differences.

I was confused, but he continued.

And some dimensions have aliens and some don’t.

Ah!  His definition of higher dimensions was basically an alternate universe.  He was working with the ‘sci-fi definition.’  I needed to change terminology, as we obviously were discussing two different things with the same word, so I said the world we live in has three spatial dimensions and time as the fourth dimension.

Time is a dimension?!

He understood and explained the concept of two dimensional space and then three dimensional space, but he was perplexed about time as a dimension.  My explanation was that you can move through time, but only forward.  With the spatial dimensions, you can move forward and backward, left and right.

I think I blew his mind at that point, so I figured we’d drop it and move on to Calabi Yau spaces another time.  In the meantime, I’m trying to decide if I should introduce him to Abbot’s Flatland.

Never ask a woman her weight…but her kinetic energy is fine August 2, 2014

Posted by mareserinitatis in math, physics, running, science.
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Today, I had one of the most awesome runs I’ve ever had.  In particular, I sustained a much faster pace than I have over a 3 mile distance.

I couldn’t help but wonder, however, about the factor weight plays in one’s speed.  As much as I try not to worry about weight and focus on being healthy, there’s this part of me that thinks it would be cool to lose a bit of weight because then I would go SO MUCH FASTER.  Or at least that’s what I tell myself.  However, I wondered if maybe I was exaggerating a bit, so I decided to check it out.

While it’s a bit of an oversimplification (that doesn’t take into account muscle tone, lung capacity, hydration, electrolyte levels, altitude adjustment, and the 18 bazillion other things that can affect a runner, even as stupid as that kink that’s still in your neck from last Thursday’s swim (okay, that only affects the triathletes here)), a quick check is to use the kinetic energy equation.

First, of course, we have to assume a perfectly spherical runner.  Or a Blerch:

The Blerch

The Blerch

(As an aside, if you don’t know what the Blerch is, you must check out the Oatmeal’s wonderful cartoon on running.  We all have a Blerch deep inside of us.)  Either way, perfectly spherical things are happy for physicists because of all the lovely simplifications we can use in learning about them.  So, if you’re a perfectly spherical runner, remember that physicists will love you.

Anyway, our hypothetical runner will have a mass (m), which is, of course, directly proportional to weight.  (Weight, of course, is also referred to as gravitational attraction, so the more you have of it, the more attractive you are, at least from the perspective of the planetary body you’re closest to.  Also, it may start to be more attracted to you if your velocity starts to approach the speed of light.  Maybe this is why many humans also find runners attractive?  Not sure.)  The unit of mass is the kilogram.  The runner will also have to maintain an average speed velocity (v), and of course your pace is inversely proportional to your velocity.  Your velocity is probably measured in miles per hour by your local race, but since we’re being scientific, we could also use SI units of meters/second.  That being said, if you double your speed in one unit, it will also double in the other.  There’s nothing fancy that happens because you’re using one unit or the other.

The kinetic energy of our runner, assuming an average velocity, can be written as

(1) KE=½ mv2

If we have the kinetic energy and mass, but want to find out the velocity, we first divide both sides of the equation by the mass and then take the square root of both sides.  This leaves us with the following result:

(2) v=√(2 KE/m)

Let’s take an example.  If we have a runner who has a velocity of 5 mph (or 2.2352 m/s) and a weight of 140 lbs. (or 63.5 kg).  If we use SI units to compute this runner’s velocity, it turns out her initial kinetic energy (KEi) is 158.63 J.

On the other hand, we don’t really need to know how much initial kinetic energy the runner has, in terms of numbers.  We can just define it as the quantity KEi. It turns out that physicists are kind of lazy about using numbers, so we’ll try to go without them because, in my opinion, it sort of confuses things. (You’ll see why later.)

How this this help us?  Well, if you want to take a drastic example, let’s assume a runner loses half of her body weight.

First, let’s establish that her initial kinetic energy is defined also by an initial mass mi and velocity vi.  (These would be the same as the 5 mph and 140 lbs. above.)  This means her initial kinetic energy can be written as

(3) KEi=½ mivi2

and her initial velocity would therefore be

(4) vi=√(2 KEi/mi).

If her weight drops by half, we can write this as her initial weight divided by 2:

(5) m=mi/2

If we put (5) into our velocity equation (2) as our new mass and keep the same initial kinetic energy, we get

(6) vnew=√(2 KEi/m)=√(2 KEi/(mi/2))=√2*(2 KEi/(mi))=√2(2 KEi/(mi))

You can see that the last part in six is basically the square root of two times our initial velocity from (3).  That means that by losing half her weight, our runner would run about 1.4 times as fast, or 40% faster.

Now what if she only loses 10% of her weight?  It turns out that (5) would become

(7) m=mi/1.1

so our new velocity would be the initial velocity times the square root of 1.1, which is about 1.05.  Losing 10% of her weight only makes her 5% faster.

After spending time looking at this, I decided that going on a massive diet definitely isn’t going to help me speed up significantly.  (In fact, if I manage to go from my current weight to my ideal, I would maybe get a gain of a bit over 1/2 mph.)  It’s the fact that the mass doesn’t play as strong a role as velocity does because velocity gets squared and mass doesn’t.  If you want to go faster, you are better off practicing running faster.

So please pass the ice cream!  I need it for my fartlek recovery.

Beautiful, elegant models March 27, 2014

Posted by mareserinitatis in engineering, geology, physics, research.
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I’m interested in the different uses of the word model.  Of course, the most common reference (outside of science and engineering) is to someone who wears expensive clothes.  Upon encountering such a model, most of us in the sciences and engineering wonder how they could charge so much for so little fabric.

In science and engineering, however, I’m discovering that I don’t like the use of the word because it’s ubiquitous and therefore nearly useless.  The problem I’ve run into is that everyone uses it but not necessarily for the same things.  In one field (or to one person), it means the equations describing a phenomenon.  In another field, it’s a computational model incorporating those equations in a specific configuration.  In yet a third field, it can describe a computational framework.  Then there are models that are simple calculations to describe inputs and outputs of a system.  And finally, I’ve also heard someone refer to it as a non-quantitative description of a process.

I’m slowly realizing that a model depends on what you and your field emphasize.  It’s used to describe an abstraction or an idea of the process, but what you’re describing as a model is extremely dependent on your training.

I think I may go back to using it to describe the walking mannequin.

A filtered education March 3, 2014

Posted by mareserinitatis in education, homeschooling, math, older son, physics, science, societal commentary, teaching, younger son.
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The older son is a lot of fun.  Despite his statements that he has no desire to go into science, he seems to get and make a lot of science jokes.  I know he’s not a scientist, but I feel comfortable that he’s scientifically literate.  As he was homeschooled, I’m feeling pretty proud of myself.

I’m more anxious about the younger son, though.  This weekend, he brought home his science homework, which focused on optics.  The kids were studying filters, and one of the questions asked about what kind of light would you see if you shined a flashlight through a blue filter and then a red one.  I asked him what he saw, and he said nothing.  Unfortunately, he was told that he saw nothing because the flashlights just weren’t bright enough, but that what he should have seen was purple.

I’m pretty sure that if I had ever been bombarded with gamma rays in the past, I would’ve turned into She-Hulk at that very moment and started smashing things.  Fortunately (or unfortunately, if being She-Hulk happens to be a goal of yours), that didn’t happen.

I find it infuriating that, throughout my years of homeschooling older son and teaching younger son math, I have constantly been questioned about my ability to teach them.  The implication has always been that I may have a degree, but they are experts on teaching.  In fact, this particular teacher attempted to take me to task earlier this year about the younger son’s math curriculum…the same teacher who apparently doesn’t understand that light and pigments work completely differently.

After I managed to calm down, I explained that light filters are like sieves, except that they only let one size of particle pass through: nothing bigger can pass through the holes, but nothing smaller can, either.  After this explanation, the younger son was able to correctly explain that the reason he saw no light from his flashlight is that the two filters together had blocked all the light.

I’m going to be watching very carefully to see what kinds of scores he’s getting on his answers and whether the teacher realizes she made a mistake.  This was very disappointing.  There was a new science curriculum introduced this year, one which I was very excited about.  The focus was supposed to be on hands-on, problem-based learning, which is great for science.  Despite that, it seems that younger son’s science education may be lacking.  What good does it do to have a top of the line science education curriculum (or math…or anything else) when our teachers don’t understand what they’re teaching?  And how is it that these same teachers can justify questioning the ability to teach material that some of us understand far better than they do?

Curriculum litmus test February 14, 2014

Posted by mareserinitatis in engineering, physics, teaching.
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litmus

 

I received the written comments back on my student evals from last semester.  I had a number of students who were very annoyed with the final project.  The previous two years, the final project consisted of a Matlab project.  After thinking about what a pain that was, I decided to change to a new project: a paper of 10-15 pages that has each student discuss their goals for getting through college.  The general consensus among those who commented was that the project required too much work for a 1 credit class.  There were several comments about how most of the other sections of this class don’t require as much work as I do, but the paper was just too much.

I’m sort of used to the comments about how much work my class is.  I state up front that they can expect 2-3 hours of homework each week…for a 1 credit class (that is, we meet once per week for an hour).  I also figure they had better get used to it, given the expectations of many of my colleagues.

I did find the comments slightly disturbing, however, because the implication seems to be that what I’m asking them to do is a lot of busy work.  In a lot of classes, many students feel that they’re spending a lot of time doing things that they will never do again outside of college.  They’re right, in a lot of cases.  I took a ton of math as an undergrad, and Mike likes to tell people that I’ve forgotten more math than he ever learned.  Sadly, the longer time goes on, the more I think he may be right.

The class I teach, however, is an academic skills class.  This means I am teaching them how to get through school, particularly in the engineering curriculum.  Do you know how to take notes?  What are the key things that are important?  Can you write a lab report?  Do you even know what area of engineering you’re going into?!

These are the things I’m trying to teach them.  My goal isn’t even to get them through the engineering curriculum, though a lot of the things I assign may be geared that way.  I simply want them to get through school and graduate.  I tell them this.  It perplexes me, therefore, how they can view setting goals as a waste of time.

I really have put a lot of thought into my assignments.  I want this class to be useful, and so I ask myself if each activity is something that will help them learn a skill they’ll need to get through school.  In a lot of ways, I’m at an advantage: college is a very constrained environment, and I can tell what skills are useful until they graduate.  After they graduate and get a job, however, their classwork may or may not be very valuable.  It’s something that simply can’t be predicted.

I have had students come back to me and say that they are really glad I taught the class and they do use the skills that I taught them.  I’m just not sure, however, how to make it clear to the freshman in my class that I really am not trying to torture them and that I do want them to succeed.  I can only hope the ones complaining about writing their goals are so motivated and driven that a lack of clearly stated goals has absolutely no bearing on their performance in school over the next 3 1/2 years.

99 bottles of…oops January 28, 2014

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Yesterday, I was helping guide some cub scouts (specifically webelos) through their scientist achievement.  One of the things we had to discuss was Pascal’s law.  Unfortunately, the instruction set on this was pretty limited: read and discuss.  That, to me, means they likely wouldn’t understand it at all, so I felt like a demo was in order.

I decided to demonstrate the pressure change in a beer bottle.  The concept is simple: fill an empty bottle with a non-compressible fluid (so water works, air won’t) and tap on the open end with a rubber mallet or even your hand.  Of course, you want to do this over a bucket because the sudden change in pressure causes the bottle to break at the weakest point, usually the seam along the bottom, and spill it’s contents.

I did this demo for the first time in front of the kids.  (I had ONE bottle of beer.  No, I didn’t imbibe in front of them…I used it to bake bread.)  It worked like a charm.  If I didn’t trust physics so much, I wouldn’t have been okay trying it cold like that.

If you don’t have a beer bottle handy and would like to see this demo, there’s a good video on YouTube:

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