Deep in the bowels of a Parisian basement, in a vault that needs three keys to open, is THE kilogram. Known as the international prototype kilogram (IPK), this block of platinum-iridium is how we define the measurement. There’s some controversy around the kilogram, however, as measurements over the last century have shown that the IPK has lost about 50 micrograms – about the weight of a grain of sand. Because of this, since 2005 members of the International Committee for Weights and Measurements have been discussing other ways it can be defined.
This is a general engineering zone, with a mix of engineers from different fields and specialities ready to answer your questions. One engineer works for Amazon, working out how to get the things you have bought online to your house, and another looks at how to make things like magazines and phones out of rocks and crude oil. There is also an engineer designing machinery to help provide safe food worldwide, one who helps people understand how to build big systems, like cities, that survive when unexpected things happen and one making gadgets for Royal Navy submarines.