15 Nov 2010

Dancing the structure of a molecule + scent vs music revisited

Some time ago I caught a glimpse of a headline about some researchers "dancing their natural science projects", more specifically a biochemist dancing the structure of certain biochemical compounds. I thought the idea was rather far-fetched and didn't give it further thought. After seeing it just recently I find myself being so very wrong... Second part of the post contains a few recent thoughts about a project on scent vs. music.

Have a look at the video below. In the start of the video I didn't see the point, but after a while things started to dawn on me.

After watching the video I realised that this did indeed illustrate behaviour of the molecules in question in a very vivid way. I'm of the opinion that one should look for as many possible ways of describing and explaining a phenomenon as possible. If a student tells you they don't understand what you're saying there is seldom any help in repeating the same words one more time. You need to find new words, some other metaphor, another mental representation.

10 Nov 2010

How small are actually the things food is made of?

How small are single plant cells, proteins, sugar molecules? What about those things that spoil our food: bacteria, enzymes? All of them are really small, but when things get this small it is often difficult to grasp that there are huge differences in smallness as well. Below is a tip on how you might get to grips with this.

When dealing with food we talk or read about proteins, carbohydrates, plant cells, enzymes, bacteria and lots of different "really small things". Enzymes react, making fruit brown, proteins and sugars react to give what we perceive as brown coloured and pleasant smelling bread crust. Plant cells absorb or lose water through osmosis to become hydrated or dried, resulting in crunchy or dry/flabby vegetables or fruit. Bacteria and fungi either help us making leavened bread or yogurt, or they spoil our food rendering it unappetizing or even unhealthy.

Usually we talk of these things as macroscopic entities: proteins = eggs, fungi = visible mould on old bread, carbohydrates = sugar in the sugar cup. However, some times these are referred to in terms of their microscopic properties, and this is among the challenges when teaching about food (many of these things are actually submicroscopic, but in educational context we commonly refer to this as the "micro level").

The concept of "smallness"
During my time of teaching, I've realised that many people in general have not reflected on several aspects of this feature:
  1. there is indeed a microscopic world behind the macroscopic sensible/tangible world, and the latter is often a reflection of the former (after all, eggs are cooked because protein molecules react in certain ways)
  2. there are huge differences in actual size between these things which we commonly just think of as "really small"