Monday, April 27, 2015

The Twilight Zone: PD Day style

This illustration is wrong. Can you see why?
It seems Barbie should not have been ridiculed for admitting she found math class tough. The Barbie doll making the confession was yanked from the shelves and the offending words banished from her vocabulary. Now, it is clear that the Ontario Ministry of Education along with quite a number of teachers in London, Ontario, are also befuddled by math.

Professional development days, or PD Days as they are commonly called, are held by the Ministry of Education to teach teachers. A recent PD Day in London focused on improving the teaching of math in city schools. The lesson contained a glaring error. This is bad enough in itself, but how this obvious blooper slipped by numerous teachers is concerning.

The teachers were told two growing puppies both gained three kg. The first dog went from a weight of five kg to eight kg while the second went from three kg to six kg. The teachers were asked: Which puppy grew the most? For added clarity, an illustration was provided comparing the growth of the two dogs.

Unfortunately, the illustration is wrong. Rather than correcting errors in proportional thinking, the illustration promotes one of the very myths the PD Day should have been addressing. The doubling of the external dimensions of something, say a figurine, does not double its weight nor double it area. Some 26 years ago, The National Council of Teachers of Mathematics noted the surprising acceptance of this myth among math teachers.

Doubled weight? Wrong!
The second dog doubled its weight. It did NOT necessarily double in height, width and depth as well. As a former art student I know this problem well. Sculptors make small scale models, maquettes, before starting the full-sized piece.

If a small sculpture of a dog takes 1 kg of clay, the same sculpture doubled in size requires 8 kg of clay. Doubling the length, width and depth does NOT double the amount of clay required but increases it by a factor of eight.

How the little dog in the illustration only doubled its weight while expanding eight times in volume is not a riddle; It is an impossibility.

In a ministry of education publication, Paying Attention to Spatial Reasoning, the ministry reports that the National Research Council calls errors in the teaching of spacial reasoning a “major blind spot . . . locked in a curious educational twilight zone . . . "

Well, welcome to the Twilight Zone, London PD Day style.

Sunday, April 12, 2015

A vegetarian cook celebrates fruits and vegetables

My wife and I just returned from Montreal after a brief visit with some Quebec-based friends . They are both vegetarians and their meals were an eye-opener.

I thought being a vegetarian was, to a great extent, simply taking standard meals and removing the meat while pumping up the vegetable and fruit component. I learned I was wrong.

My friends celebrate vegetable and fruits. Meat may be missing but it is not missed. A curried dish that I would have served with chunks of chicken hidden in the sauce was simply delicious on its own. No chicken; no loss.

I'm on a low cholesterol diet. I'm half way to understanding the approach practised so successfully by my Montreal friends. Now, back in London I'm going to try to change my attitude and maybe, just maybe, I'll see less meat but more variety in my menus.

I'm going to start tomorrow with a cauliflower dish cooked in a tagine. This meal should say North Africa and not vegetarian. It should delight the eye and satisfy the pallet without raising red flags drawing attention to the lack of meat.

If this works, I'll post the recipe and a picture soon.