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Systems Language
Posted by Niall Palfreyman on 2/3/2010
In Reply To:Systems Languagg Posted by Tim Joy on 2/3/2010
Tim Joy schrieb:
> What is in the mind of my students when I say "stock" or "level" or "accumulation"? The stock market, a tool with water bubbles, or something about GPA's?
I find the German word 'Bestand' useful here (my students are German).
It means exactly the same as 'stock', but it's more a part of everyday vocabulary that the English word. Everyone knows immediately that a 'Bestand' represents the current status of something which has varied incrementally in the past, but I don't think that is true, for me at least, of the word 'stock'. I had to learn slowly what a stock was. In my work with biology students I use the term 'species', simply because the concentrations of chemical species are something with which my students feel comfortable. Would the word 'quantity' work, I wonder?
While 'quality' can jump erratically from one value to another, a 'quantity' needs to be depleted or incremented over time.
One additional point here: While I personally like the bathtub metaphor, I don't particularly find that it strikes any wonderful chords with my (science-based, undergraduate) students. I get the impression that they, like Bill Braun's school director, prefer very concrete metaphors with obvious relevance to their daily work.
> When you describe a causal connection, what various phrasings make it clear to someone in the middle grades? someone in high school? someone with a poor math background?
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I think I usually say something about a causal connection 'explaining why something changes'. In first-year physics we talk about Galileo's kinematics as opposed to Newton's mechanics, and I say that the difference is that Galileo describes _what_ happens, whereas Newton explains _why_ it happens in terms of forces which cause changes. I use the example of throwing a ball in the classroom: when a student throws a ball, it simply flies off into the distance, but if I first tie it to a piece of string whose other end is fixed, it flies in a circle; in the second case the string exerts a force which causes the direction to change.
> When you describe closed loop, what words and phrases help seat the idea in your hearer's mind?
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Here I'd love to hear some responses. The first closed loop we come across is exponential population growth, and I've still never found a really successful way of making the closed-loop aspect clear.
Best wishes,
Niall.
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