Electronics, Teaching, and a Quiz

By cjohnson | January 11, 2006 4:50 pm

Well, I’ve been tinkering with computer code and bits of electronics to try to get stuff for my big class (Physics 151) working properly. I’ve set up a dedicated laptop computer (it’s an ibook…. it’s running Mac OS X) to handle all the teaching and admin tasks for my undergraduate classes and everything works like a dream….but not at the same time. Sigh. So the classroom is equipped with IR receivers that then are connected to the computer. What I can then do is ask questions (or play games…or some combination of the two) of my class and they can respond with the personal response units that they have in their possession (bought elsewhere)…..I can then flash up the results in real time, discuss them, etc… It’s a great way of getting real-time response to whether what you just taught them actually makes any sense to them at all. Real in-class interaction.

The problem is that the receivers connect via to an RS-232 serial cable plug. My computer needs a little dongle that turns the standard USB port into such a port. I have one. I installed the driver software. I plugged it in. It works.

The other reason I’m using this particular computer is so that I can present all my lectures with the added functionality (and downright niceness and coolness) of Keynote. I was using pdfs (generated by Keynote) on my previous windows-based (hissss) teaching machine (and I refuse to use Powerpoint). This program is way superior to either. Well, I have lots of overlays, multiple builds, etc, and I like to walk around and wave my arms about and that way keep the class interested as I lecture. I don’t want to stand by the computer like a statue to trigger all that functionality, and so I use a wireless device to control the computer from afar, freeing me to be animated. It’s the same one I use when I give other presentations (research seminars, etc) from my main (research and other stuff) powerbook, so I know it well. It’s great. It works.

The problem is when you have them working at the same time. Then one or the other is not actually working. Sigh. This is not good, since one wants to project the questions one wants them to answer from one’s presentation, and then run the answer-gathering software, at the same time, etc….. you see the problem.

Well, I think I might have it sort of fixed now (after hours of playing with it)……It seems that there is an ordering issue that I have to remember…. need to test it a few more times, as the next big class is tomorrow.

In the meantime, here’s something else from the class’ first day. The first class is usually taken up with logistics of explaining how the course works, etc….there’s a lot to tell them since we have several components, and several ways of getting points toward your grade…. the other thing we do is as five questions to be answered on a tear-off front page of the syllabus and handed back to us.

    We care most about the first question:

  1. Why are you signed up for this section instead of one of the other ones? If you have a course conflict please identify the course.
  2. Well, you don’t care about that one, but it does help us determine how to balance things between different sections (same stuff, different lecturer). I could use the help right now, since I have 185 or so students in my section (there are people sitting on the stairs), while the other section has 75. So we want to know why! The fact that my colleagues’ section is at 9:00am while mine is at midday is clearly a big part of the problem…..Several of the answers had “I’m not a morning person”.

    But then there are four other questions. Bear in mind that these are freshman-level students. We’d like them to get into several useful habits, as budding engineers and scientists: (1) Ability to make useful estimates and rough computations (2) Having a good sense of the relative sizes of important things (3) Realizing what’s a convention and what’s not…. It’s simply interesting to see the answers to the following questions (compiled by my colleague Chris Gould (yes, he of the aforementioned Science Fair)):

  3. How big is an atom? (Use any units you prefer.)
  4. How far is it to New York? (Use any units you prefer.)
  5. How far is it to the nearest star? (Use any units you prefer.)
  6. How many people holding hands would it take to form a line stretching from Los Angeles to New York? (Rhetorical Supplement: How hard might it be to get that many people!?)

My favourite answers (some of which I’d not heard before from previous years) include:

“One atomic unit.”

“Really small, but bigger than subatomic particles.”

“Six hours on Jet Blue”

“By car, it’s three days, depending upon how many breaks you take.”

“Really, really, really small.”

“Farther than I could walk.”

“One astronomical unit.”

“If George Lucas is lecturing on campus at the moment, it wouldn’t be too far.”

“Wicked small.”

“7.9 light-minutes.”

“About the size of a ping-pong ball in comparison to a football field.”

“Is this a trick question? Atoms aren’t big!”

“It would be very difficult but not unprecedented. It was attempted in the Simpons and they failed, so it would be very difficult.”

“100 really tall giants.”

“Regular sized people …. or dwarfs…. be more specific.”

“The population of China, because China can do anything. They’re huge.”

“To be horrible and answer the rhetorical question, if we get enough money to pay them it would be easy (if we get cheap labor from Japan or India, it would be even easier)…..(but plane tickets might be expensive).”

“It depends. I have a 6’8″-ish wingspan. If it were a bunch of babies, it would take – a lot.”

“It would be a lot of people, but my neighbour would like to point out that his arm span is way longer than a baby’s, so it all depends.”

So there you have it. It’s going to be an interesting freshman physics class with at least have of the 185 being budding comedy geniuses…. I love this job!

(Feel free to add your own answers.)


CATEGORIZED UNDER: Academia, Science
  • Julianne

    Hi Clifford — I’ve been having great success with using colored index cards instead of the clickers. 15 bucks at office max gets you enough for 5 colors of cards for 300 students. It looks a bit like a North Korean pep rally when they answer, but it’s a very quick way to gauge their understanding, with no risk of technology failure(*). The minute that it takes them to rummage in their stuff and find the right card also snaps them out of their stupor.


    (*) with the exception of the one kid who’s red/green color blind.

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford


    That would be great, except that the computer allows me to log everything that they respond, to several questions per lecture, and use it later to generate useful data about participation, etc…also alllows for automatically generating and presenting histograms of the responses that they can all see….and it can feed back in interesting ways to their answers if you re-explain and ask them to answer the question a second time around.

    I do like the idea of using coloured cards though…I might well use that for some other thing….



  • http://www.amara.com Amara

    Asking questions the first day of class is a cool way to begin; I like to do that too. However, I only have two questions for them (they write the answers on a paper, which I hold until the last class), each question serves a different purpose. One is a basic astronomy question (my course is an intro astro course for humanities students), so that I can gauge the level of their astronomy knowledge. The other question asks what they wish to learn in the class. Not only does it help me to customize the course (keeping the essentials) to their interests, but sometimes their reasons for taking the course are wild and creative. Fun.

  • fh

    Fun questions! We had these sort of “Fermi Problems” for physics freshers (part for them getting a feel of handling units and part for getting a feeling of the orders of magnitudes of reality) when I was teaching my first tutorial, no joke answers though as it counted towards their grade.

    Questions included estimate the speed of a snail in atomic radii per millisecond and stuff like that…

    I love the 7.9 Lightminutes answer! Very creative! I guess the ultimate answer for that would be 1AU then.

  • http://tingilinde.typepad.com steve

    I once asked someone what the fuel economy of a car is in inverse acres…

    Years ago I taught a section to get biology types interested in fermi calculations for their speciality. Most of the class was homebrew, but I based it on John Harte’s excellent “Consider a Spherical Cow”

  • spyder

    In honor of Albert Hoffman’s 100th birthday today, and in keeping with the theme of strange new responses to wonderfully vague and ambiguous questions, as i prepare for this late night flight to Basel–here is a good clean fun joke about an entrance exam:


    The day finally arrived; Forrest Gump dies, and goes to Heaven. He is at the
    Pearly Gates, met by St. Peter himself. However, the gates are closed as
    Forrest approaches the Gatekeeper.

    St. Peter said, “Well, Forrest, it is certainly good to see you. We have
    heard a lot about you. I must tell you, though, that the place is filling
    up fast, and we have been administering an entrance examination for
    everyone. The test is short, but you have to pass it before you can get into Heaven.”

    Forrest responds, “It shor is good to be here, St. Peter, sir. But nobody
    ever told me about any entrance exam. I shor hope that the Test ain’t too
    hard; life was a big enough test, as it was.”

    St. Peter continued to say, “Yes, I know, Forrest,
    but the test is only three questions. First: What two days of the week,
    begins with the letter T? Second: How many seconds are there in a
    year? Third: What is God’s first name?”

    Forrest leaves to think the questions over. He returns the next day and
    sees St. Peter, who waved him up, and said, “Now that you have had a
    chance to think the questions over, tell me your answers.”

    Forrest replied, “Well, the first one-which two days in the week begins
    with the letter “T”? Shucks, that one is easy. That would be Today and

    The Saint’s eyes opened wide, and he exclaimed,
    “Forrest, that is not what I was thinking, but you do have a point, and I
    guess I did not specify so I will give you credit for that answer. How about
    the next one?” asked St. Peter. “How many seconds in a year?

    Now that one is harder,” replied Forrest, but I thunk, and thunk, about
    that and I guess the only answer can be twelve”

    Astounded, St. Peter said, “Twelve? Twelve? Forrest, how in Heaven’s
    name, could you come up with twelve seconds in a year?”

    Forrest replied, “Shucks, there is got to be twelve:
    January 2nd, February 2nd, March 2nd. ! ..”

    “Hold it,” interrupts St. Peter. “I see where you are going with this,and
    I see your point though that was not quite what I had in mind…..but I will
    have to give you credit for that one, too. Let us go on with the third and
    final question. Can you tell me God’s first name”?

    “Sure”, Forrest replied, “its Andy.”

    Andy?” exclaimed an exasperated and frustrated St. Peter. “Ok, I can
    understand how you came up with your answers to my first two questions,but just
    how in the world did you come up with the name Andy as the first name of God?”

    “Shucks, that was the easiest one of all,” Forrest replied. “I learnt it from the song.

    St. Peter opened the Pearly Gates and said: “Run, Forrest, run!”

    Give me a sense of humor, Lord. Give me the ability to understand a clean
    joke, to get some humor out of life and to pass it on to my friends.`

  • Aaron

    “About the size of a ping-pong ball in comparison to a football field.”

    … Bill! Bill! Bill! Bill!

    (Why, yes… I am a product of American public television! ^_^)

    p.s. I could only answer the second one, but I think I did pretty well: ~6 hours * ~50 mph = ~300 miles. The actual distance from Detroit to New York is 650 miles — ­close enough for astrophysics! 😉

  • Mike Molloy

    Good joke, spyder, but everyone knows that God’s first name is Harold. (“Our Father, who art in Heaven, Harold be thy name.”)

  • http://blogs.discovermagazine.com/cosmicvariance/joanne/ JoAnne

    I once had a student calculate on an exam that the radius of the earth was 29 meters. I later quizzed the student if that made sense to them, and he/she had never thought of looking over their answers and ensuring they made sense!

  • Chris W.

    Mostly off-topic, but maybe these could be addressed in a future CV post:
    Digital Universe — an interview with Wikipedia’s co-founder Larry Sanger on his new project, plus a new article on Wikipedia’s prospects and recent travails, Can Wikipedia Survive Its Own Success?.

  • http://eskesthai.blogspot.com/2005/10/microstate-blackhole-production.html Plato

    Of course I would like such expansion on the digital world walkabouts too, and how, such applications become “instrumental” in our assessments.

  • http://xenobiology.blogspot.com indrax

    Note all figures are from my head, these are just my estimates, and could be wildly wrong.

    1. I am not a morning person
    2. ok Human DNA is 8 feet long, and has around 600 MB of information, which would be 300 million base pairs. A base pair is what? 4 or 5 atoms ‘tall’, tops. I’ll say 1.2 billion atoms in 8 feet. 150 million per foot. 5 million per cm. 500 million per meter, so.. 2 nanometers?

    3. 8 car hours.

    4. 8 light minutes, or 93 million miles. (I could tell you that asleep)
    light goes 11.8 inches per nanosecond, so that would be about 48 billion feet.

    or to alpha centauri: 4 light years, which is about a parsec (right?)

    5. Ok, light can go around the earth 7 times in a second, and there are 24 main time zones. so that’s 148 time zones per second. The US covers 4 time zones, so that’s 1/37th of a light second so .027 light seconds
    Assume 5 feet per person, that’s 5 light nanoseconds. We need to cover 27,000,000. 200K people would cover 1 mill. so.. 5.4 million people.

    I suggest offering pizza and free music downloads.

  • serial catowner

    Yeah, good luck with that part where everybody clicks if they don’t understand….

  • http://blogs.discovermagazine.com/cosmicvariance/clifford/ Clifford

    Actually, when they don’t understand and you get answers all over the place, that can be fun too! Because then you get them (following Mazur’s “Peer Instruction” stuff) to try to convince their neighbour with a reasoned argument. Then they click again…… it almost always clears things up… or at least narrows things down to help you sort out what the conceptual logjam was….


  • http://countiblis.blogspot.com Count Iblis

    Perhaps physics should be taught this way in highschool.

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