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400

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We humans like round numbers.  We don't celebrate the 23rd annual summer fete or the 49th anniversary of an organisation but the 25th or 50th respectively. This is why the quantity of carbon dioxide in the atmosphere has hit the headlines this week. The daily measurement at Mauna Loa on Hawaii has passed 400 ppm (parts per million) for the first time. Not so much a cause for celebration; more a cause for commiseration  The actual measurement was 400.03 but was subsequently revised down to 399.89 (but what is fourteen hundredths of a part per million between friends). Breaching this threshold was not particularly unexpected but it is symbolic in human terms; it is a memorable number. But what are the implications of exceeding a CO2 concentration of 400 ppm? Some climate change skeptics will be quick to highlight the scientific evidence that shows the atmospheric CO2 has been at this level and higher on the past. They are absolutely correct. Somewhere in the ...

Testing Times

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What is the point of exams? Is it to test the candidate's knowledge of the subject or is it to test the candidate's skill in passing exams? In theory at least, it should be the former but when there is a lot riding on the result there is a tendency towards the latter with students placing more emphasis on training to pass the exam rather than gaining a deep understanding of the subject. The student may gain some knowledge of the subject, but only those parts that will gain most marks in the exam as part of a strategy to maximise the result for minimum effort. This doesn't only apply to academic exams.  Similar strategies can also be adopted for all sorts of tests.  For example, if a car maker wants their car to get a good fuel efficiency rating they can work on scoring better in the test, rather than improving the car's performance.  They can use non-standard high performance lubricants, disconnect the alternator, over inflate the tyres, remove door mirrors and ...

What I Learned During Earth Hour

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A book and a wind-up torch. During Earth Hour, I learned the following: The origin of apples; A little about the last few months of Leon Trotsky’s life before being exiled; That I can still read a book in the dark with a torch (like I did as a child, under the blanket after bed time); And, thanks to @glasgow_kat, that petrochemical candles have much higher emissions than an electric light. Earth Hour is a fantastic way to highlight the problem of climate change in solidarity with people across the globe but it is not enough on its own. Switching the lights off on landmarks from Sidney Opera House to the Eiffel Tower to the Empire State Building for one hour is purely symbolic. Even switching them off permanently would be insignificant. The kind of reduction in fossil fuel use that we need to achieve would be more like everyone everywhere turning off the lights, heating, air conditioning, refrigeration, computers, televisions - everything for an hour. Not just once a year...