A metre is a comfortable measurement. The length of a pike is about one metre, that of Finland is a million, and a cubic metre is one thousand litres. A thousand litres of water weighs a tonne. Easy! It must have been a walk in the park to develop and adopt such a simple and functional system. Or was it?
The “pear” that survived the Great Fire of Turku
Some physics instruments can be quite captivating due to, for instance, their peculiar shape or material. Take this pear-shaped object known as Nicholson’s hydrometer, for example. With the anniversary of the Great Fire of Turku of 1827 taking place on 4 September, we decided to select as the object of the month one of the treasures that survived the blaze and now features in our collection. What is this pear-shaped, streamlined, metallic object known variously as an areometer, a gravimeter, a densimeter and a hydrometer? The names tell us very little about the object itself, so let’s find out more.
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