The Golden Rule of Experimental Science

Michael de Podesta gives us his golden rule of experimental science; do it quick and then do it right As an experimental scientist at the National Physical Laboratory (NPL), I am frequently asked to measure things that others have found difficult, or pronounced impossible! And as I face each one of these new challenges I am guided by the ‘Golden Rule’ of experimental science: Do it quick. Then, do it right. The rule encapsulates the simple fact that when one is doing something for the first time, it is hard to anticipate all the things which might happen. I believe this rule applies universally. Of course it applies to students in laboratory classes who plan out their measurements carefully, only to find that something they hadn’t thought of changes so much that the experiment is a waste of time. Or they find that they have taken so much data in a ‘dull’ regime that they ran out of time to make measurements in the ‘interesting’ regime. But it applies to professional scientists too. Before beginning an experiment which eventually took six years to complete, I was able to carry out a ‘quick and dirty’ experiment to give me an idea of the relative sensitivity of a large number of factors that I previously did not have the experience to properly assess. And I discovered several things in the process, most importantly that I had massively underestimated of the amount of water vapour in our otherwise ultra-pure gas. And reading the best-selling Thinking, fast and slow by Daniel Kahnemann I realise that the Golden Rule is merely a specific example of a wider rule of thumb. Kahnemann calls it seeking an ‘outside’ view when planning an activity, and he recommends it as a remedy for a cognitive bias towards optimism that he calls the ‘planning fallacy’. This refers to the tendency when making a plan to consider all factors one knows about, but not to actively seek knowledge of ‘other’ factors. The Golden Rule embodies an experimental approach towards seeking knowledge of relevant unanticipated factors. Another way is obviously to read about other people’s experiences in journals and text books, but this is hard for experimentalists, leading to the epithet: Two weeks in the laboratory can easily save a whole afternoon in the library. This sums up perfectly the fact that ‘spending an afternoon in the library’ can feel harder than ‘getting on with the project’. Happy experimenting. :-) Michael de Podesta is a Principal Research Scientist at NPL. The ‘experiment which took six years’ was a measurement of the Boltzmann constant which he  hopes will lead to a redefinition of the unit of temperature, the degree Celsius. More information and a video explanation can be found here: http://www.npl.co.uk/news/race-towards-a-new-temperature-definition