Uncertainty in Science

Possibly one of the most important concepts that should come out of a Science Education course is that Science does not provide certainty – it simply can’t. It’s all about probability.

The experiment we do in school to ‘prove’ that solids expand when heated, does nothing of the sort. We take one metal ball and show that it passes through a ring when cold but not when hot. Now explaining why this is not a proof is a nice excercise in itself. Initially students are slow to come up with any reason. To be honest they just don’t know what I’m on about. but then you give them a couple of examples: it’s only one metal, it’s only being heated over a rather narrow temperature range etc, and they quickly get the idea and can apply it to other experiments.

Why is this important?
To take one example, the whole notion of theory versus fact versus hypothesis is very ambiguous, but yet these words often get thrown around when knocking the theory of evolution. The implication is that because it is a ‘theory’ it is not well accepted in the scientific community; the word has a different meaning in common parlance than it has in the science world.

Secondly, scientists are often pilloried because they won’t state categorically that powerlines / mobile phones / radiated foods are safe. the implication is that if these were safe then science could prove it and say so. the reality is that you can never prove anything to be absolutely safe (life is carcinogenic) and we need to bear this in mind when weighing up the evidence.

The American physicist Richard Feynman talks about uncertainty in science – albeit in relation to his views on religion – in this clip from youtube.

So you would think this concept of uncertainty in science would get mentioned somewhere in the syllabus – at Junior or Senior Level.

But not a dickie


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