Archive for March, 2011

Measles Outbreak Hospitalizes Four Children

March 31, 2011 1 comment

Yes, and it could have been prevented.

The outbreak happened in the Twin Cities area of Minneapolis. Since measles immunization is highly effective at preventing measles, how is it a that an outbreak like this could have occurred?

According to the Minnesota Department of Health, a recent outbreak of measles in the Twin Cities area was caused in part by former doctor and medical researcher Andrew Wakefield’s influential but fraudulent study suggesting a connection between child vaccination and autism.

So why weren’t the children vaccinated?

Several of the parents informed the Health Department they had avoided the mumps, measles, and rubella (MMR) vaccine out of concerns their children would be at risk of autism.

If you read this blog at all (or any other skeptic blog, for that matter) you know this already. But once more, with feeling…


Not only has Wakefield’s original study been shown be of poor quality, it has also been alleged to be fraudulent. Many larger studies have shown absolutely no correlation between vaccines and autism.

None. Zero. Nada. Zilch. Nil.

Ok, I’m starting to get worked up. It happens when I talk about vaccines especially.

Why? Well usually when a scientist’s outlandish claims get debunked it is an “I told you so!” situation.

But when children (or anyone) get hurt or hospitalized as a result of those outlandish claims, it becomes a “Bang your head against the wall because this could have been prevented” situation.

Maybe we could call this a “Wakefield” situation; a “When Are Kids Ever going to Forgive us for letting Idiots Endanger their Lives with Debunked science” situation.

The reality is starting to set in, as Dr. William Schaffner, chair of the Department of Preventive Medicine at Vanderbilt University, lays out:

Hospitalizations and deaths have occurred—all preventable, had the children been immunized. In the U.S., some parents withhold vaccines; others stretch out the vaccination schedule, leaving children susceptible to disease for longer than they should.

I don’t know if the damage caused by that original Wakefield paper will ever be fully undone. But that doesn’t mean we can’t try to undo as much as possible.

Teaching Electricity and Magnetism: Part II

March 30, 2011 2 comments
This is the second part of my posts about teaching Electricity and Magnetism (EM). Part I can be found here, which dealt with the confusion of students in learning electricity and magnetism together. Part II deals with a paper looking at ways to help improve teaching methods for EM. The paper is entitled “Using multimedia learning modules in a hybrid-online course in electricity and magnetism“.

When I was still TAing (about 2 years ago) the University was starting to implement a new way of performing tutorial sessions. They were going to do it online. This was done by the students logging into a virtual classroom with the other students and were able to type out questions to the TA. The TA was in a computer lab somewhere and outfitted with an electronic on-screen writing tool (don’t ask me what it’s really called) and would work out problems on their screen by hand, which the students were able to see in the virtual classroom.

When asked if I wanted to participate in this type of tutorial, I refused. Call me a dinosaur (I’m only 26, but whatever) but I wanted to be in the room with the students when I taught them.

But do online and multimedia learning tools help? Or are they worse? That was the topic of this study.

A multimedia learning module (MLM) was developed by the Physics Education Research Group at the University of Illinois at Urbana Champaign and implemented as a pre-lecture assignment to students in an introductory physics course. MLMs are interactive online exercises which include flash animations which introduced physics concepts to the students. The MLMs were about 12-15 minutes long.

So the goal of the study was to determine if using MLMs prior to learning the concepts in class resulted in better grades for the students and a better student experience. The study tried them out in an introductory Electricity and Magnetism course in the Fall of 2008 at California State Polytechnic University at Pomona.

They used two different sections of the course as the control group and the experimental group. The control group (N = 48) had only the traditional coursework. The experimental group (N = 34) used traditional coursework in conjunction with the MLMs. To make sure any increase in performance was not simply due to increased time spent on the material in the experimental group (i.e. classtime + time spent on MLMs) the amount of time spent in the class was reduced by one-third for the experimental group.

Students in the experimental group viewed the MLMs prior to learning the material in class. Both groups were approximately equal in academic performance  prior to taking the course, as determined by a survey.

Student performance after the term was measured by a multiple choice test, as well as the results of answering questions in class using a personal response system called a  “clicker“. Students were also asked to fill out a questionnaire to rate the usefulness of different aspects of the course, such as the textbook or the MLM.

Students who used the MLM showed an 8% higher normalized gain than those in the control group (45% compared to 37%) in their multiple choice test. In addition, students who used the MLMs answered a slightly higher percentage of in-class clicker questions correctly (60 +/- 4.0%) compared to the control group (54 +/- 3.0%). This leads to an effect size of 0.25, which is considered a small effect.

Finally, students rated the usefulness of the different course material on a scale of 1 (not useful at all) to 5 (extremely useful). Students in the experimental group rated the MLMs higher (~2.5) than the course textbook (~1.3).

So does multimedia course material improve student performance? Well these results show that it is no worse than traditional coursework. One thing to note is that any increased improvement of the group which did MLMs compared to the control group is very small. With a sample size of about 40 students in each group, it is difficult to draw any firm conclusions.

In addition,

It is worth mentioning that the comparison of final exam scores between students in the control and those in hybrid-MLM group showed no significant differences.

So at the end of the day, students did roughly just as well in both groups.

But this is an interesting study nonetheless. Probably the best thing to do would be to offer the MLMs as an optional and additional resource to the students, without cutting out the in-class learning time. Everybody learns differently, whether it be through visual stimuli, auditory or simply repetitiveness. The important thing is to make resources available so people of all learning styles can benefit.

I felt I could teach my students best face-to-face, so I declined to use the new fangled technology for online tutorials. But I understand they are still being used, and some students actually prefer them. So I guess in the end, this study showed that no single manner of learning is better than any other. Do what works for you and stick with it.

Sadaghiani, H. (2011). Using multimedia learning modules in a hybrid-online course in electricity and magnetism Physical Review Special Topics – Physics Education Research, 7 (1) DOI: 10.1103/PhysRevSTPER.7.010102

Teaching Electricity and Magnetism: Part I

March 29, 2011 2 comments

When I was a physics TA, there were two topics which always got the students easily mixed up. The first was Newton’s Laws; students had a hard time knowing which law to apply in what situation. But with a little practice and teaching, they soon found that you could follow a very specific procedure to solving any problem involving Newton’s Laws, which helped immensely.

Electricity and Magnetism (EM) was different, however. There really is no set procedure for solving an EM problem. There are strategies and guidelines, but no step-by-step ways of solving EM problems like there is for Newton’s Laws.

I’m not the only one who has noticed this either. Two papers were published this month in Physical Review Special Topics – Physics Education Research. The first was entitled “Interference between electric and magnetic concepts in introductory physics“.

This study looked at the difficulty students had in determining which direction the force on a charged particle would be, if it were in either an electric or a magnetic field.

For a positive charge in an electric field, the force is always in the same direction as the field. If the charge is negative, the force is in the opposite direction of the electric field. Students generally don’t have a problem with this rule; that is, until you introduce the concept of a magnetic field to them.

In a magnetic field, the force on a charged particle is always perpendicular to the magnetic field lines. So when you get to the end of the term and you ask an EM question, students often (understandably) get confused which rule they should use.

The main hypothesis of the study, therefore, was that students have trouble because they learn about electric fields first, and then apply those lessons to working with magnetic fields.

You can test this hypothesis by seeing if the opposite is true. Does learning about the magnetic field first negatively affect the way students answered questions about electric fields?

The subjects (I mean, ‘participants’ hehe) of the study were students in an introductory physics course at The Ohio State University. The students were asked to answer EM related physics questions. They were split up between groups which had learned i) nothing about EM, ii) electricity but not magnetism, iii) magnetism but not electricity, and iv) having learned both. The order in which the questions were asked and some other variables were randomized for better results. Below is an example of the type of question the students were asked.

Can you get the answer to this question? For the left hand side the answer is 'e - Into Page' and for the right hand side the answer is 'f - Out of Page'

There are actually several results from this study, so if you are interested in them all I encourage you to read it (it is free to read). But the main hypothesis turned out to be true:

directly after instruction about magnetism, many students answer that the direction of the force on a charged particle moving through an electric field is perpendicular to the electric field, presumably by employing the same right-hand rule that was learned for magnetic forces. Thus, despite the fact that directly before magnetic force instruction students were answering electric force questions correctly, up to two weeks (and possible longer) after they learn about magnetic force, they answer electric force questions as though they were magnetic force questions.

So the authors actually showed that it is not electric fields or magnetic fields alone that confuse students, but after learning both they get them mixed up, which makes sense. It doesn’t seem to matter, either, which they learn first. After learning both electric and magnetic fields they still get confused.

The authors suggest (and I agree) that to combat this the instructor must frequently point out the distinction between electric and magnetic forces. It is a difficult thing to get a feel for, kind of like learning the offside rule in hockey.

A good strategy is always visual demonstrations. Take for example this video of MIT professor Walter Lewin demonstrating the perpendicular magnetic force (jump to around 46:40 for the demonstration):

So what else could we do about students having trouble with EM? What about online and multimedia tools?

That will be the topic of Part II of this series.

Scaife, T., & Heckler, A. (2011). Interference between electric and magnetic concepts in introductory physics Physical Review Special Topics – Physics Education Research, 7 (1) DOI: 10.1103/PhysRevSTPER.7.010104

Sweeeeeet Aurora Video

March 29, 2011 Leave a comment

I think auroras are one of the coolest things on the planet. Along with bacon and beer.

This video was featured on the Astronomy Picture of the Day website. Two words:

Awe. Some.

Land Mine Detection With Stuff That Smells Good

March 28, 2011 Leave a comment

Punta Espora, Chile, Tierra del Fuego side of the Strait of Magellan - minefield warnig near the ferry terminal

At the March meeting of the American Physical Society, an abstract was presented entitled “Detection of Nitro aromatics via fluorescence quenching of pegylated and siloxanated 4, 8-dimethylcoumarins”.

The BBC reported that this study utilized curcumin, which is found in the spice turmeric and is one of the key ingredients in many curry powders.

Now, I wasn’t at the meeting so I may be wrong, but the abstract does not describe using curcumin, but coumarins. Coumarin is also a fragrant chemical compound, but it is not found in turmeric. It is actually used as a rodenticide and was banned as a food additive in the United States in 1954.

If I’m lucky enough to have a reader who knows more about this work, or was at the conference and saw this talk, I would very much appreciate a clarification. In any case, the research is still pretty interesting.

The abstract described the work of a team of researchers at the University of Massachusetts Lowell. The group reported their research into using optical sensors to detect chemical explosives, such as those found in land mines.

Optical sensors work by reacting the molecules released into the air of the chemical explosive. The optical properties of the sensor material changes after interacting with the explosive. Measuring these changes in optical properties is called fluorescence spectroscopy.

The group created co-polymers and tested their use in fluorescence quenching, which means that when you shine a light on these polymers in the presence of explosives such as trinitrotoluene (TNT), the light given off by them would dim.

The BBC also reports that

The team, which is funded in part by the US government, is already in discussions with a company to develop the technique into a portable detector device.

which, given the huge problem of land mines in war-torn countries, could turn out to be very useful.

Hey Canada, Who Should You Vote For?

March 28, 2011 5 comments

I know, I know. This is a science blog, not a political blog! But elections are quite important to the world of science as well and deserve attention.

Canada is headed for its 4th election in the last 7 years! It is getting a bit ridiculous, but then, so is the world of politics.

No matter what country you are from, when an election comes up people inevitably ask who you are going to vote for. The political diehards will urge you to “get informed!” and read up on the issues before making a decision.

If you are like me though, you leave this kinda stuff to the last-minute, maybe watch the debates and then vote for the same party you have the last few times. Admittedly, this is probably not the most, well, scientific way to go about things.

So if you need a bit of help deciding who you should vote for, you should try the ‘Vote Compass’ on CBC’s website.

The Vote Compass is a questionnaire of about 30 questions which ask you things like

Should Canada pull all of its troops out of Afghanistan immediately?

and then you simply answer using radio buttons for options like “Strongly Agree”, “Agree”, etc.

While certainly not rigorous, it is a good jumping off point to learn about the issues and get a sense of what political party’s views match up with your own.

My results, you ask?

My 'Vote Compass' Results

Taking into account the issues I find most important, my results (not surprisingly) put me closes to the NDP. If all issues were weighted equally, I would be closest to the Liberal party.

So in deciding who you will vote for, learn about the issues; you should also try to ignore the one thing Canadians hate most about election season. (Warning: You may only get this video if you from Canada. Enjoy!)

It’s the Juno Awards!

March 27, 2011 2 comments

I love music; almost as much as science!

Yes, the Canadian version of the Grammys is being broadcast tonight. The Junos celebrate excellence in Canadian music, though “excellence” is defined very loosely.

Generally the award categories are dominated by the likes of Nickelback, Michael Buble and Justin Bieber. But thankfully, there is a lot more to Canadian music than these guys.

Nickelback at the 2009 Juno Awards.

The Arcade Fire was awarded “Best Alternative Album” last night at the awards gala (they also won the Grammy for Best Album this year) which was great.

Said the Whale was awarded “Best New Group” who have some really catchy tunes like “Black Day in December” and “Camilo”.

There are a couple of categories I will be watching closely: “Best New Artist” and “Songwriter of the Year”. Hannah Georgas has been nominated for both, and I think she deserves to win. Seriously, you can’t listen to “Bang, Bang, You’re Dead” without getting it stuck in your head. (The video is pure low-budget gold!)

So even though some of the awards are clearly based on record sales and not talent (Katy Perry won for ‘Best International Album’. Seriously??) I hope some talented songwriters and singers get the recognition they deserve.

Rock on!