CSI Ypsilanti

Here is the Ruben's tube video I promised, along with photos of the crime scene absorption spectroscopy activity we did today (which was the most stunning success I've had all year). The activity was framed as a crime scene investigation evidence analysis, the handout for which can be found here.

I will probably explain this all at tonight's TF meeting, but I got fed up with students not paying attention and spending so much of my efforts on getting them to care, so I decided to try a new approach. I know that there are some students who are focused and want to learn when they come to class, but they are often thwarted or held back by their less driven peers. For today's activity, I told the class that I would be doing an activity at the back lab table that would be covering a lot of information and that I wouldn't have time to repeat myself a lot for people who weren't paying attention, were distracting others, fighting, and generally acting like third graders. That being the case, I offered them an alternate writing assignment that they could do instead if they did not want to participate, or that I would ask them to do if they did participate, but caused trouble. I made it very clear, however, that the activity and the writing assignment were equally valid for them to choose, so if they did not participate in the activity, it would not reflect negatively upon them.

Given these options, about 15 students initially joined me for the activity, with about five of them deciding in the first minute or two that it didn't look interesting enough and opting for the writing instead (which I found odd, since I don't ever remember a time in high school where I would rather write than do an activity). This left me with a self-selected group of 10 interested and engaged students, all of whom were completely focused the entire hour. At the end of the hour, Ms. Hardy told me that some of the students who did the activity were talking about how cool it was and that they had made some of their peers who decided to not participate regret their decision. This is exactly what I had hoped for! Hearing their peers talking about how cool something is is far more effective and piquing students' interest than hearing me talk about how cool it is. I plan to take this same tack next time and hope that there will be more participation because of the positive word of mouth.

On another note, I sort of wonder how much of the success of this activity was because of the self-selecting group and how much was because it was just a really neat activity (not to boast, but I impressed myself with this one). I sometimes think that a contributing factor to lack of focus during classroom activities is simply because they're not interesting or engaging enough. Who wants to focus on something they find boring?

Ideal gas producing close to ideal results

Good news! I was right about my chilly propane tank. I was worried that the low flow rate may have also been due to the regulator valve connected to the outlet hose, which I would have been less than pleased about, since I wasn't in the mood to buy a new regulator. I'll have a link to the video of the first successful trial of the Rubens tube once I figure out where I can easily host a 27MB file.

Additionally, after initial testing, it occurred to me that the wavelengths of the tones I was playing on my guitar were longer than the length of the tube, so except for some of the higher notes, the flame waves showing up are actually representative of one of the harmonic modes being played. I think this is a neat idea to incorporate into my presentation (which I'll give tomorrow), since the class had just been learning about interference and how waves can be linearly combined. Perhaps being able to show a visualization of one of the harmonic modes individually might be a good way to illustrate how the constituent parts of a complete wave can be parsed.

Ideal gas producing less than ideal results

The first version of my Rubens' tube is built, but the results are less than impressive. It's hard to light, the flames are very small, and the standing waves that should be generated by a constant tone aren't very defined. However, it recently occurred to me that my having snagged the propane tank from the gas grill sitting outside in 20 degree weather may be the cause of my problems. Having been outside all winter, the chilled propane in the tank is going to be at a relatively low pressure, which would explain the emaciated-looking flames I observed. Time to bring the propane tank inside and give it some hot cocoa and a warm bed to sleep in to help it re-pressurize.

Perhaps this would be a good example to introduce the ideal gas law to the chemistry class.

"It's not that I'm lazy, it's that I just don't care..."

(This post has been brewing for a while; sorry about the lengthiness...)

As most of us have experienced and have mentioned at the last TF meeting, classroom behavior, distractions and lack of focus seem to be the largest barriers to effectively communicating, well, anything. This lack of focus and motivation also seems to be reflected in the class grades and district graduation rates. That said, I wondered if the students in Ms. Hardy’s classes were aware of these two significant indicators and what their general attitude toward school was. I was half expecting a response resembling the line from Office Space I quoted in the subject of this post, so put together a small survey to try to get at the answer. A sheet with the following questions were distributed to all of Ms. Hardy’s chemistry and physical science classes (not just the ones I’m in):

What grade are you in?
What is your favorite class?
Do you think doing well in school is important?
Are you happy with your performance in school?
What percentage of students do you think graduate from YPSD schools?
Do you think you’re going to graduate from high school?
Do you want to go to college?
Do you know the difference between a bachelors, masters and PhD degree?
What do you want to do after high school / college?
What’s your favorite song?

I received 86 responses, which constitutes a response rate of about 73.5% of the total number of students in the classes surveyed. Most of Ms. Hardy’s students are sophomores and juniors, though there are a few seniors scattered among her classes. The most popular class was science, in general, followed by lunch/none. The other survey answers are summarized in the table below The range of responses to the question about the YPSD graduation rate was from 15-100%, but the average guess was 65.74%, less then 1% away from the actual rate of 66.3%. This reminds me of something I heard from my statistics teacher in high school about how if you have a jar of jelly beans and ask a group of people to guess how many are in the jar, the individual guesses will not tend to be very close to the actual answer, while the average will tend to be very close to the actual answer, given a large enough group.


I was heartened by the nearly unanimous support of academic achievement and desire to attend college, though the disparity between those who think doing well in school is important and those who think they're doing well perhaps indicates a long-term motivation but a lack of a short term motivation (since I believe all of the students in my classes are fully capable of doing well).

I found the responses for after high school / college aspirations to be pretty interesting. The most popular goal was to become a doctor of some sort (including veterinarians and psychologists), followed by making money. I was almost sort of glad that someone mentioned the general goal of “making money” (though I hadn’t hoped this generic desire was quite that popular), since I found a very germane chart from the department of labor statistics.


I sorted through the list of goals and attempted to assign a minimum level of education associated with each particular profession. For “money”, I semi-arbitrarily assigned a minimum of a bachelor’s degree. One student who listed “money” also stated the specific value of $600 million, for which I thought at least a professional degree sounded reasonable. Given these assumptions, 63% of the students had goals that required at least a bachelor’s degree.

About 58% of the students said they knew the difference between the different types of college degrees, though I think the true number may be lower than this, since one student who said he/she knew the difference also included an incorrect explanation. I had explained this at the beginning of the last semester, but I wouldn’t be surprised if that first presentation didn’t exactly make an indelible impression on them. Given that many of their long-term aspirations would require a higher degree, I think I’d especially like to reiterate this point when I present the results of their survey.

I tacked the favorite song question on to the end of the survey because I wanted some ideas of what to use for demonstrating the Ruben’s tube I had mentioned in a prior blog post. I hadn’t stated on the survey that the song had to be appropriate for school, because although I had anticipated a lot of the songs wouldn’t be usable, I still wanted to know their favorite songs regardless. However, after sorting through all of the responses, approximately zero of which I had heard of before, I found that about four or five of the 86 suggestions were remotely appropriate for school. In fact, I was sort of shocked by some of these songs, and showing the printed lyrics to some of my friends provoked various horrified expressions. Doubly disappointing was, not only were they almost universally explicit, they weren’t even explicit to any particular ends; that is to say, a lot of the rap songs I listened to didn’t seem to even be about anything, but really just a five-minute string of offensive phrases. There were a few I found mildly amusing, but they were in the minority. In the interest of full disclosure, I am definitely not a rap fan (in fact, it may be one of the only music genres I actively dislike); however, trying to as objective as possible, I’ve come to the personal conclusion that Lil’ Wayne is an awful, awful, embarrassing excuse for a rapper, which makes me wonder why he’s so popular among the students in my class. I suddenly have new found respect for Emenem and Mos Def.

Anyhow, seeing as my original plan of using student suggestions for the Ruben’s tube demo isn’t really going to work, I’ve decided that I’m going to use this musical gem that was called to my attention the other day: The Ypsilanti Theme Song (The play button is at the bottom of the article.) Apparently this is the official Ypsilanti city song, selected by the city council in 1983. Maybe it seemed like a good idea at the time… At least the synthesizer break in the middle of the song should produce some nice standing flame sine waves.

The two classes I’m in at Ypsi are first and third period, so I usually help Ms. Hardy with lab prep or work on presentations during second period, but the other day one of the physical science students came to third hour about fifteen minutes early (I think she had come to school late), so I discussed the results of the survey with her. I had mentioned the large disparity between the percentage of students who believed doing well in school was important and the percentage that were actually happy with their school performance. She proceeded to enumerate the difficulties she and her classmates experienced in their neighborhoods that were impediments to succeeding academically. She asked me at some point if I grew up with both my parents. I told her yes, to which she replied (to the best of my recollection),

“Well, no offense, but it’s a lot different growing up with just a mom, or like some of these kids without even a mom. People in my neighborhood aren’t always telling you that you can succeed and do well. They usually tellin’ you that you ain’t no good and you ain’t going to make nothin’ of your self.

Both my older brother and sister are mechanical engineers now, and they gone and succeeded in life, but now when they come back to the neighborhood, everyone thinks they a couple of snobs now. ‘Oh look at them big shots now. They forgot where they come from. They think they so special!’ “

The more she spoke, the more it sounded like she was trying to convince me that my line of inquiry was a futile endeavor, implying that this was the way things were and there was no point in trying to do anything about it. I asked her if she thought my survey and what I was trying to achieve from it was a waste of time. She quickly changed her tone and said, no, it was definitely worthwhile and that she thought many people in her class had probably never been asked what career goals they have and hadn’t really connected day-to-day class activities and achieving those long term goals.

The original focus of this project was originally to use some sort of student generated data to support why things like paying attention in class, following instructions, etc. are important (i.e., “You have all acknowledged that you want to do better in class, so here is an easy way to improve.”). Though I was already aware of the impact of the students’ lives outside of school upon their academic performance, given this student’s emphasis on life outside of school, I think I’ll broaden the scope to include a student discussion about what they think success is. Essentially, though there was almost unanimous consensus about the importance of college, I’m curious as to whether they responded that way because that’s simply what is expected in an academic environment and if they might have any different responses when asked to answer in the context of their own upbringings. If people in this particular student’s neighborhood look upon “white” success with disdain, what are some alternate definitions of success?

Today, Ms. Hardy started the new semester with an emphasis on rules, what they are, why we have them, and what constitutes appropriate and inappropriate classroom behavior. I was glad to see that she was taking a somewhat harder line on recording behavioral infractions—this is not to say that I’m glad that she is being strict for the sake of being strict, but that I think she is making an effort to be consistent with enforcement of the rules. For the most part, even during a free collaboration period, the class was quieter and more attentive than usual. Hopefully this will stick and be reinforced by my presentation of survey results and discussion of class goal setting on Wednesday.

Pre-break demonstrations

As I mentioned in an earlier post, I was going to try to use more counterintuitive demonstrations to engage students. Ms. Hardy asked that I do one of these demonstrations on the 18th, their last day before the break. In my digging to find experiments of this nature, I discovered the Briggs-Rauscher oscillating reaction (see a video of it here). At this point, the students have seen reactions that cause precipitates to form, states of matter to change, and changes in color. However, once the reaction takes place, they're usually completed in a matter of seconds. The Briggs-Rauscher reaction is impressive, not only because three clear liquids are mixed to make a nice yellow solution, but because the solution then oscillates between yellow and blue for several minutes. It's a somewhat complex reaction (actually two simultaneous, competing reactions), but because it's right before the break, I didn't think explaining the details of the reaction wouldn't really be necessary, since they probably wouldn't have the attention span for something like that right before going on vacation anyhow. I was hoping it would be more like a treat for them to see and ask about when they get back.

Well, that didn't pan out because the necessary chemicals weren't available and Ms. Hardy told me that what they have is pretty much what they're stuck with, since the purchasing budget for the year has already been allocated. Perhaps I could order these chemicals for next semester with TF funds?

In lieu of that demonstration, I'll be doing two others: decomposition of hydrogen peroxide and triboluminescence. Both the chemistry and physical science classes have talked about energy that is consumed or released in reactions, and the physical science class has talked about types of reactions, so both of these demonstrations will have relevance in each class. The decomposition reaction HOOH-->2(H2O)+O2 is catalyzed by catalase, an enzyme found in many living organisms, including humans (it makes the hydrogen peroxide bubble when you put it on a cut) and baking yeast. The baking yeast can be added to consumer strength hydrogen peroxide to produce the decomposition. It produces a nice foam and the presence of O2 can be demonstrated by reigniting a wood splint that has just been blown out. Not only does this give a tangible example of a decomposition, it will also give me a chance to talk about how a catalyst affects the activation energy of a reaction.

Most of you have probably seen triboluminesence before. If you take a wintergreen Lifesaver and crack it with your teeth in the dark, you can see blue sparks. I think this is a neat demonstration of conservation of energy: the mechanical cracking imparts energy upon the electron, which transfers its energy to another atom, which vibrates and releases the energy mostly as UV light. Because wintergreen oil is fluorescent, the UV light causes blue sparks to appear.

I'll be presenting these tomorrow, so we'll see how it goes.

Playing catch-up

It's been a while since the last update, but over the past month there have been a lot of days where school has been canceled, half-days where my classes don't meet, or when the students have been taking tests, so there's been less to report on than I would like. However, I did give another presentation a couple weeks ago that seemed to have gone over much better than my first attempt, given the slightly different way I approached the material. This time, in addition to including as many illustrative photos as possible, I also kept myself from delving into long-winded explanations of unnecessary detail and used the presentation, covering different types of mixtures (View it here), to lead into an activity during the second half of the class (See the instructions here). I found it easier to engage the students this time around and found them more willing to offer up ideas for examples of different types of mixtures. I think this was partially because the material was more familiar and accessible, compared to the idea of standards, and also because the students have become more comfortable with me since my last presentation and find participating in my talks to be a nice change of pace.

That said, there are still some students who seem to make it their job to be as disengaged as possible. There is one girl who sits near the front of the room, right in the middle, and the completely flaccid expression on her face and the use of her arm to prop her head up--lest it fall to her desk in boredom--pains me every time. I don't think I could be that unenthusiastic about anything if I tried. That is the breed of student to whom I was trying to tailor my talk, but it seems I have a ways to go still.

One of the persistent problems I've noticed in Ms. Hardy's class is that the students frequently don't bother reading the instructions for things before asking for help. Although I don't mind explaining things if they don't make sense, there are too many students to go around explaining the entire activity or lab to everyone individually. Because of this, you'll notice in the last slide of my presentation the emphasis on reading the instructions before giving up and asking for clarification. However, at the last minute, I found out that there was not enough glassware in the classroom to have each of the substances for the activity measured out for the students in advance. I asked Ms. Hardy during her planning period just before the Physical Science class if there was enough time to change the instructions to indicate that they were to measure out certain substances from a communal container at the center bench and print out new copies, but she said that wouldn't be necessary, that I could just write the modifications on the board and tell the students to refer to them as they worked. It seemed reasonable enough, but as I had predicted, this led to confusion and a lot of people asking, "What beaker of vinegar? There ain't no vinegar. Ms. Hardy, what do we do?" Even many of the students who were participating in the talk seemed to have turned on their selective hearing when I started talking about the modified instructions. I think I was on the right track with trying to streamline the instructions and encourage the students to try everything independently before asking for help, but I have to avoid making any changes after I say something or hand out written instructions.

Anyway, once everyone finally got on the same page with what they were supposed to do, I think the activity was a success. I had the students create a homogeneous mixture, a heterogeneous mixture, and a heterogeneous suspension by mixing sugar and water, oil and vinegar, and water and cornstarch, respectively. I was particularly excited to be able to do this activity, since the water and cornstarch mixture produces a non-Newtonian fluid that many people are probably familiar with, either from playing around with it at home, or from watching people walk on pools of it on programs like Myth Busters. Although there wasn't too much excitement at the water and sugar mixture, the students were endlessly fascinated with this liquid? solid? cornstarch mixture. I think it was a nice demonstration of how something that seems familiar can act in a non-intuitive way. I want to try to incorporate as many of these examples into future activities as possible, since I think a fascination with and a desire to understand those non-intuitive properties is a good way to lead into a pursuit of studies in a scientific field.

Speaking of counterintuitive physical principles, I've recently discovered the fascinating concept of thermoacoustic refrigeration. A friend of mine sent me this article that profiles a new three-in-one refrigerator/oven/electric generator that is powered by a wood fire. Of course, the fire doesn't directly power the other components. They're powered by harnessing the vibrations of the pipe through which the water being heated by the fire passes. The electricity is produced in a pretty straightforward manner, via a linear actuator that acts as a generator, but the refrigeration is the really neat part. A thermoacoustic heat engine is used to induce cooling--essentially, sound is used to keep your food cold. I was blown away by this, since this was a concept with which I had no familiarity. I promptly searched the web for ideas of how to demonstrate this to my students. As luck would have it, a professor at my undergrad university had published a paper on how to build a tabletop demonstration thermoacoustic refrigerator (check it out). It looks pretty simple, so I plan on constructing one of these and presenting it next semester when the physical science class gets to their unit covering waves.

First Presentation

I've been meaning for a while to post the first presentation I gave, but every time I thought to do so, I was never on the computer on which it was actually stored. Finally though, here is the link: first presentation. I feel that this first attempt was a pretty profound flop. I think I overestimated the students' prior knowledge when I was assembling the material, and underestimated the amount of time needed to present the material, which in turn caused many of the students to lose interest (though that may have already occurred in the first few minutes).

In my mind, I had envisioned talking about the different ways units are standardized, starting with time and length, which are based off of natural constants, an then mass, which is still just a block of metal. I thought the irony of that was kind of amusing, but I think I was the only one in the room who thought so. Part of the problem was that I don't think the idea of basing a unit off of a natural constant--or at least the ones I talked about--made sense. I didn't anticipate most of the class not knowing what an atom was, or at least having a vague concept of what it might be, so the time standard didn't go over so well. I didn't expect that they would know what a light-second was, but I figured that would be fairly easy to explain, though that was assuming they were familiar with the concept that light travels. Again, another flop. Of course, I tried to fill in these gaps during the presentation, but it was hard to quickly explain fundamental concepts like that in a way that allowed the students to immediately understand significance of how they connected to the rest of what I was talking about. Anyway, when I came to my big punchline, "And the mass standard is just a block of metal! Crazy, huh?"--no, I didn't deliver it quite such a cheesy manner--I could hear a chorus of crickets.

In the presentation I included a couple of little cartoons I had drawn containing visual puns, hoping to add some level of entertainment, but I'm not sure if anyone got them.

In the second part of the presentation, I wanted to communicate the importance of keeping attaching proper units to all measurements and to make sure conversions are used where they're needed, so I referenced the famous NASA Mars orbiter fiasco where the orbiter was destroyed because of unit mix-up. A few of the students perked up when they heard about expensive things getting destroyed, though they seemed to be more interested in Mars exploration missions than in unit conversions. That was okay by me though, since at least a few of them were engaging me at this point and asking questions.

On the last slide of the presentation, I included a couple of equations that I was going to use to explain what a Newton is (the unit leading to the NASA failure). By that time though, I realized that given what I perceived to be a lack of interest and/or understanding of the first half of the presentation, I wasn't going to try to explain new concepts right at the very end. If I recall correctly, I gave this presentation the day after I started realizing the very disparate levels of math preparation in the class, so I decided that if simple fractions were difficult for some, introducing the concept of units as fractions wasn't a good idea at this juncture in time.

All in all, I think this first presentation was more of learning experience for me than it was for the students. Hopefully next time, knowing what I know now, those roles will be reversed.