Wednesday, March 3, 2010

A Hierarchy of Learning

Tēnā koutou katoa – Greetings to you all300th Post
Heat Exchanger - artist ken allan
My work environment has been a bit noisy lately. The school is having the roof renovated. The building’s air-conditioning units have been disconnected during the time of this refurbishment.

It being summer, there’s a need to open windows and to bring in industrial air-conditioning units to maintain a workable atmosphere within the building. At the beginning of this week, contractors wheeled two of these units into the space close to my office area, plugged them into the mains and switched them on.

Other units were similarly introduced at points throughout the building. The Science teachers who worked in the areas, including myself, viewed this activity with amusement. It was evident that the contractors knew nothing about thermodynamics.

It sucks

The heat exchange part of an air-conditioning unit operates in a way similar to a refrigerator. In normal use, the unit sucks warm air from the room through a cooling unit and filter.
Fresh air from outside the building is drawn in through windows and other openings to replace the heated air expelled during the process.

The resulting chilled air is blown back into the room while the removed heat is air-pumped to the exterior, usually through a duct in a window.

In the case of the units that we observed, there was no such venting. Instead, the hot air from the action of the cooling unit was being pumped back into the room. It was as if a fridge had been turned on and its door had been left wide open. In such a circumstance, the fridge does nothing more than make a noise and heat the room.

The overall effect of the air-conditioning units being used in this way was not unlike that of using large blow heaters. In no time, people started to complain about the rising temperature.

A little learning

Science is a wonderful thing. Its principles are being utilised in just about every piece of technology that contributes to our lives today. Of course, an understanding of scientific principles isn’t always necessary to use or install the equipment that puts these principles into effect.

There are at least three levels of understanding that can allow one to realise the significance of a scientific idea, such as the thermodynamic principles that were put to use in the construction of the air-conditioning units:

  1. It works provided certain conditions are met according to a recipe for installation. For the air-conditioning unit to be effective, it has to be functioning and have its required vents clear, one of which has to be ducted to the exterior.

  2. It works as it follows the thermodynamic idea that heat can be pumped by using a small amount of energy that is eventually released as heat (which is why the fridge with its door open does nothing more than heat up the room).

  3. It works, and its function can be explained by thermodynamic principles:

    a) energy can neither be created nor destroyed,

    b) heat energy is released when a gas is compressed so that it condenses to a liquid and this same heat is taken in when the liquid is allowed to evaporate
    – this is what happens in the heat exchange unit of a fridge,

    c) some energy will always be wasted when heat energy is pumped using mechanical means – entropy is always increased as a consequence

Understanding at level 3 can be achieved by senior secondary school Physics students.

Level 2 can be understood by able students of Junior Science.

Working recipes that define the factors that are important in level 1 need only be followed when it comes to the correct and appropriate installation of a piece of technology in general circumstances.

The example that I unpack here shows how related learning can apply at various levels to the curriculum. What is significant is that the most elementary levels of learning are still important to the correct use of technologies that involve sophisticated principles in their design and construction.


As it happens, the contractors were notified by Science teachers about the correct use of the air-conditioning units which were immediately switched off. Appropriate locations near windows were then found. Necessary ducts to the outside of the building were fitted correctly to the machines within 24 hours.

Through all this, the cicadas continued their sibilant summer chorus.

Ka kite anō – Catch ya later


V Yonkers said...

Wasn't there also problems with poisonous gases without proper venting? As they are machines, they may give off carbon monoxide (this is a problem with portable air conditioners in the US at least).

I am surprised though that they would make that mistake even without the science to back it up. Many in construction have a tacit knowledge of geometry and physics, but couldn't explain to you why something works the way it does. Just that it works.

Blogger In Middle-earth said...

Tēnā koe Virginia!

I don't know so much about carbon monoxide issuing from the machines in our office. I'd be hard pushed to figure where it originates from as they are powered by electricity.

Your point about 'just that it works' is valid and is aligned with my point about a recipe for installation. The principle is that if you follow the instructions, it will work. Indeed, a lot of Science is explained that way. Tacit though it may be, it doesn't really provide a valid explanation for why it works - just that it does.

Catchya later

V Yonkers said...

Ken, I think there are different levels of tacit knowledge just as you outlined different levels of formal learning.

My parents had a contractor who identified a mistake in the design of a triangular shaped counter. When he showed it to us, we used the Pythagorean theorem to check the calculations. He was able to eyeball it as his worker began to mark it out. His worker did not have the ability to make adjustments, but the contractor did. Obviously, he had some tacit knowledge of the pythagorean theorem which his employee did not.

Does this make sense?

Blogger In Middle-earth said...

Kia ora Virginia!

I think you are right about the existence of various levels of tacit knowledge. I can summarise few:

knowing that a ratio formula exists for constructing a right-angle in a triangle without any other knowledge of what it is, what it's called or how it works
knowing that the ratio formula exists and is called The Theorem of Pythagoras, but having no understanding of how it can be used is another
understanding that the famous Pythagorean 3:4:5 ratio of side lengths of a triangle exists but having no other insight into the other similar ratios or further knowledge of how they can be applied is another
yet another is understanding that the area of the square on the hypotenuse of any right-angle triangle is equal to the sum of the areas of the squares on the other sides
knowing how to apply this principle using geometrical drafting tools would be even another level higher than any of the aforementioned ones.

It is this continuum (and beyond) of different knowledge, understanding and skill that makes me wonder about how the theorists, some of them educators, can draw (a) precise line(s) between tacit and implicit knowledge. I have even heard it said by some that memory is not necessarily associated with learning!

Either I'm missing something entirely or my learned colleagues cannot see this example learning continuum (that I summarise a nano-part of here) the way I see it.

Catchya later

V Yonkers said...

The way that you describe this, however, is very linear. Isn't it possible to skip a step and still have a deep understanding of a concept?

I think, for example of language. How many of us English speakers could explain the difference between say and tell? Yet, we can distinguish when to use one or the other given the circumstances. There are rules, but we rarely learn them in school. I only know of this distinction from language teaching in languages that do not distinguish between these two words. It is similar with the distinction between "ser" and "estar" in Spanish.

Thus, you have an odd circumstance in which native speakers have less "knowledge" about the rules of use or grammar than non-native speakers. However, native speakers have a deeper understanding, albeit tacit, due to the way in which they have learned the language.

Blogger In Middle-earth said...

Kia ora Virginia

I think you may have misunderstood my hierarchical list. I did not put it up as a hierarchy of how one learns and certainly did not mean it to be used as a hierarchy of steps in learning.

It is simply a hierarchy of different knowledge/skill that people may have implicit in their own understanding (or not) of a complicated principle such as the Theorem of Pythagoras.

I have no doubt that some learners may make quantum leaps in their learning and not necessarily go through stages that might correspond to the individual stages that different people may be at. In fact, my hierarchy is really nothing to do with such stages of learning, though one could argue that it could be interpreted that way. I apologise if I have been misunderstood.

Indeed, the list in my previous comment, by my own admission, is extremely incomplete. It only appears to be linear as that is how I listed parts that I gave as examples.

Of course there will be a whole complexity of different understandings, and to use the word continuum might even suggest a linearity which I know doesn't really exist.

The point I tried to put across (and I also attempted to bring this out in my original post) is that of all the levels of learning (tacit or otherwise) around a particular idea or principle, often the most rudimentary is all that is required in order to understand that there are important criteria that must be met in order that a complicated system, such as an air-conditioning unit, will work.

It's when a crucial part of the necessary understanding is missing that mistakes can be made when attempting to apply what's known and what is believed to be all that's required.

Catchya later

V Yonkers said...

That's much more clear to me now. And to extend what you have said, when there is that breakdown, one of the difficulties is to identify the problem and then to identify what can be done. Some people are very good at just figuring out what needs to be done, while others are good at finding those that may have that knowledge. Then there is the third and fourth options, just ignoring there is a problem (i.e. letting the building get hotter and hotter) or recognizing there's a problem, but hoping someone else will deal with it!

Blogger In Middle-earth said...

Tēnā koe Virginia

I was relieved that, in the case of our workplace air conditioning units, common sense prevailed when teachers took the initiative to pass on useful information. That quickly brought about an adjustment to a situation which, presumably, was satisfactory to all parties.

Even the contractor, who brought in the machines, had the opportunity to learn something new and constructive out of it all.

Thanks for discussing this.

Catchya later

HVAC Man said...

According to me its work provided certain conditions are met according to a recipe for installation.