Science Education in High Schools

from http://www.ckasr.com/

Teaching is a craft; what works wonders for one instructor and group of students may have mediocre results in a different class. So many variables affect success that it’s difficult to objectively assess the impact of one particular teaching technique, let alone an entire educational philosophy. Even success has its shades of grey. Long-term goals should be prioritized, but in practice, short-term goals are often given reign. Time-tested dos and don’ts exist, and in practicing the craft of teaching, one has to implement a variety of strategies and take constant precautions against mounting obstacles.

I do not have evidence that education in high schools is presently facing more obstacles than it was a generation ago. But  increasing corporatization has made it more prone to gimmicks and gadgets and more inclined to ignore some time-tested guidelines. Rather than lingering in generalities, I would like to focus on examples that I know well: how evolution is not part of the required senior curriculum in Quebec. Of course, there is nothing stopping a school from offering a general biology course featuring evolution as a senior elective, but in most schools, current requirements leave little room for such a course. Sadly, some states in the U.S. still debate whether creationism* should be taught alongside evolution, as if the former was actually a competing theory—in fact, it’s not even a scientific hypothesis. But is Quebec any better by not exposing the majority of its senior students to the central organizing principle of the life sciences ?

Aside from the irrational exclusion of evolution, the new science program that is part of the Reform needs major repairs. Since 2007, one of two options, either Science & Technology or Applied Science and Technology, has been a required course for all grade 10 Quebec students seeking a general diploma. Both courses are over-ambitious in scope. In fact for the 3rd year in a row, the ministry has had to trim down the list of 111 topics for final exam purposes.  Enriched students who take an additional science course study these topics in a little more detail, but more from a variety of subjects are piled on as well. At a French teachers conference, one of the presenters argued that the science approach in Quebec is equivalent to having a “Foreign Languages” course in which students would be expected to learn German, Chinese, French and Umbundu from a single teacher. The Ministry of Education seems to be taking its sweet time in creating a separate technology course, as is done in Massachusetts, which presumably inspired them to introduce technology into the curriculum in the first place.

In the chemistry program, electrochemistry and redox reactions have strangely been left out. These topics play a key role in respiration, photosynthesis, batteries, and corrosion. You would be hard-pressed to find a chemistry course anywhere in the world that has done likewise. Even the publisher of the ministry-approved textbook (Quantum) found the exclusion to be an odd decision and chose wisely to still include the chapters within its covers.

All senior courses involve a lab component that counts for 40% of the grade. An emphasis on labs is commendable but having unstandardized evaluation of a difficult-to-mark competency only serves to inflate grades. In CEGEP, all science courses base 85 to 90% of their grades on theory. And most CEGEP teachers agree that the new program is doing a poor job preparing students for biology and physics. Our colleges are not doing things anywhere near perfection either, but that will be the topic of another blog.

* Here’s the lighter side of  persistent creationism in the public sphere. It’s from season 2, episode 4 of Murdoch Mysteries, set in Toronto at the turn of the 20th century. In a murder mystery involving dinosaur fossils, Constable George Crabtree’s eccentric imagination temporarily reconciles science with religion .

Good Things Come to Those Who Are Patient

There is a classic high school demonstration in which a few drops of the glycerin(CH₂OHCHOHCH₂OH) are poured on top of a pile of potassium permanganate (KMnO₄) powder. At first nothing seems to happen, which of course begs the question: “Sir, what’s supposed to happen?” which in turn begs the cliche-reply, “Good things come to those who are patient.” Then just as the chatter of disinterest begins to break the silence, white smoke appears, and within seconds, a spectacular violet flame erupts, leaving behind a crusty residue and a harsh smell that, in the absence of a fumehood, grates on the throat and lungs.

It is often said that science allows both young and old adults to regain the curiosity of childhood. Good demonstrations lead to numerous questions. Why is the start of the reaction delayed? Why does it start at all without any mixing or heating? Why does the steam appear before the flames? Why is the flame violet? Are there any practical applications of this reaction?

The activation energy, the energy that must be absorbed in order to get the reaction going, is small, which is why it proceeds unaided. But although relatively small. But small does not imply nonexistent, so it still borrows some heat from the air. The appearance of steam before that of flames suggests that this is not a one-step affair. The mechanism probably goes through more than one intermediate.
The equation is just a summary of the overall reaction, giving no hints of what ensued behind the scenes.
14 KMnO_4(s) + 4 C₃H₅(OH)_3(l) –>7 K₂CO_3(s) + 5 CO_2(g) + 16 H₂O_(g) + Mn₂O_3(s) In the late 1950’s gentlemen named Kenneth B. Wiberg and Klaus A. Saegebarth investigated the mechanisms of permanganate oxidations, in case you want to pursue the matter.

The flame is violet due to the excitation of the electrons of the potassium ion. Delayed Aerial Ignition Devices (DAID), which shoot a stream of flaming ping-pong balls, make use of this reaction when controlled fires are deliberately set from helicopters.