Wednesday, 7 September 2016

the DNA journey

Yesterday, I came across this short film, as usual, looking for something completely different at Film English.

“This should be compulsory”, says one of its protagonists, talking about the DNA test. I am not sure about that. Danish scientists questioned the logic behind these tests (as any scientist would do). In absence of national reference datasets (what is “100% Icelandic”, for example?), the results of comparison do not seem to make much sense.

Still, I think it’s a great, if scientifically flawed, short. I did show it today to my students (all in their early 20s) and saw tears in their eyes. They might have not understood half of the language used in the film but they’ve got the message. Watch it.

Wednesday, 10 August 2016

the romance of science

From Uncle Tungsten by Oliver Sacks:

Scheele was one of Uncle Dave’s great heroes. Not only had he discovered tungstic acid and molybdic acid (from which the new element molybdenum was made), but hydrofluoric acid, hydrogen sulfide, arsine, and prussic acid, and a dozen organic acids, too. All this, Uncle Dave said, he did by himself, with no assistants, no funds, no university position or salary, but working alone, trying to make ends meet as an apothecary in a small provincial Swedish town. He had discovered oxygen, not by a fluke, but by making it in several different ways; he had discovered chlorine; and he had pointed the way to the discovery of manganese, of barium, of a dozen other things.

Scheele, Uncle Dave would say, was wholly dedicated to his work, caring nothing for fame or money and sharing his knowledge, whatever he had, with anyone and everyone. I was impressed by Scheele’s generosity, no less than his resourcefulness, by the way in which (in effect) he gave the actual discovery of elements to his students and friends – the discovery of manganese to Johan Gahn, the discovery of molybdenum to Peter Hjelm, and the discovery of tungsten itself to the d’Elhuyar brothers.

Scheele, it was said, never forgot anything if it had to do with chemistry. He never forgot the look, the feel, the smell of a substance, or the way it was transformed in chemical reactions, never forgot anything he read, or was told, about the phenomena of chemistry. He seemed indifferent, or inattentive, to most things else, being wholly dedicated to his single passion, chemistry. It was this pure and passionate absorption in phenomena – noticing everything, forgetting nothing – that constituted Scheele’s special strength.

Scheele epitomized for me the romance of science. There seemed to me an integrity, an essential goodness, about a life in science, a lifelong love affair. I had never given much thought to what I might be when I was “grown up” – growing up was hardly imaginable – but now I knew: I wanted to be a chemist. A chemist like Scheele, an eighteenth-century chemist coming fresh to the field, looking at the whole undiscovered world of natural substances and minerals, analyzing them, plumbing their secrets, finding the wonder of unknown and new metals.

Monday, 20 June 2016

collectively known as cells

There are few things as demotivating as discovering that in the end, in spite of (or maybe thanks to) all your efforts, your students learned absolutely nothing. Some of mine, apparently horrified by the exam study guide I presented them with, sent me a list of their own questions. That surprised me a bit but hey, sure, why not. And so, I have incorporated some of these questions into the exam, in a hope that this class at least would know some of the correct answers. Naturally, I was wrong.

Here’s an illustration.

The following three questions refer to the figure below.
  1. Identify the cells A, B and D. What is the name of the process C? (4 points)
  2. If the cell A has n chromosomes, the cell B has      chromosomes and the cell D has      chromosomes (2 points).
  3. Both cells A and B are collectively known as                    .
Easy peasy, even for those who were absent or asleep 90% of the time. Right?

And here are some unexpected answers, from three different students.

  1. Identify the cells A, B and D. What is the name of the process C? (4 points) *
    1.              Luan Zi             
    2.                Jing Zi             
    3.              Shou Jing             
    * I'm gonna to write chinese, because I don't how to write in English, you can search internet
Althought it is not in my job description, I did that search and should say that the (Mandarin) Chinese terms are correct. Except the symbol is not even Chinese (it’s just this student’s doodle of cell D), so it doesn’t count.
  1. If the cell A has n chromosomes, the cell B has   r   chromosomes and the cell D has   m   chromosomes (2 points).
I can’t say it is wrong. Just a bit too generic for my liking. Ditto this:
  1. Both cells A and B are collectively known as        cells        .
Here’s another one. I lifted this question from the textbook, but you don’t really need to know anything to solve the problem. Or so I thought.
  1. It takes just 1 minute for a bacterium to add 30 000 nucleotides to one DNA strand undergoing replication. The rate of replication in this bacterium is   5 000   nucleotides per second.
  2. * I don't have a calculator to determine this.

Friday, 18 March 2016

evolve or perish

In my first two-and-a-bit months working as a science teacher, there were only a few things that actually worked. And when I say “worked”, I mean made those incredibly lazy and bored pupils of mine to pay any attention for more than a minute. In case of Evolve or Perish, it worked for a good half an hour with Grade 7. They even might have learned something about geologic periods.

The preparation is minimal: you just have to print out the two pages of the game. Then tell the students to trim and glue them together to make a “board”. That’ll keep them busy for additional ten—fifteen minutes. If you have even more time to spare, you can print out the black-and-white version and then ask them to colour it. Then you’ll need dice and counters. I bought a box of four dice and I don’t know how many counters in a Chinese shop for €1. Three-four players per board work the best.

I didn’t expect that the Grade 11 students, better behaved but even more bored, to enjoy it as much if not more than Grade 7. But here they were, suddenly wide awake, rolling their dice and shouting “¡Ă‘oss!” when landing on “blast to the past”. What’s more, when they finished, they started from the beginning. One team played two games, another three games. All without me telling them what to do. Marvellous.

Saturday, 12 March 2016

are you organised?

I spent all Thursday evening marking their work. Friday morning, in school, I discover, to my horror, that I can’t find this pile of papers. Next thing I know, a girl (one of my best students) is coming to my class and asks, “Mister, did you correct our work?”


“Yes I did, but it seems that I forgot to bring them in.”
“Don’t worry, you did well.”
“How much did I get?”

It’s my turn now to say “Oh” (silently). Think, teacher, think.

“You did everything correct apart from one question.”
“Which one?”
“The one nobody answered correctly, by some reason.”
“Which one was that?”
“I’m trying to remember. I’ll let you know when we have a class.” (We have a class with them today. the last period.)

Later, a boy is coming to my class when I am about to go. Another of my best pupils. After his grade, no doubt.

“Mister, mister, did you have time to check my work?”

I’ve been teaching here for two months and they still don’t know my name. We have a conversation very much like above.

“Sorry, I have to go now. See you in the afternoon.”

In the afternoon, I finally remember the one question nobody had right. I tell kids what was the correct answer. Also, that I bring their papers on Monday.

“Mister... are you organised?” the clever boy asks.

I want to tell him that no, not really. But my inner teacher doesn’t want to give him such a simple answer.

“Of course I am organised. Look at me. All depends on the adverb that you place before ‘organised’. A person can be well organised or poorly organised. Still ‘organised’. You guys are well organised.”
“I am not very well organised”, says another student.
“Yes you are. You always bring your homework in.”
“You have to see my room. It’s a mess.”

I recall our university lecturer in physical chemistry, some 30 years ago. Once he told us that instead of saying “mess” it is more polite to say “high entropy”. For example, “you have high entropy in your department”. I tell the kids that the bedroom mess is a consequence of the Second Law of Thermodynamics. You simply can’t organise your homework without increasing entropy around you. They don’t understand the entropy bit but seem to like the idea.

“Bye, mister.”
“Good bye. See you Monday.”

At home, no sign of the papers. I check my bag again. Of course, they were there all along. I am so organised, I don’t need any adverbs.