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Full Version: The Kilogram Gets Redefined
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https://www.bbc.com/news/science-environment-46143399

Here's a little update in the science world, the kilogram is getting a brand new definition. Before the change takes place on May 20, 2019, the kilogram is being defined by the mass of a platinum ingot know as "Le Grand K". At the General Conference on Weights and Measures, it had been voted in favour of getting rid of the "Le Grand K" definition and replace it using an electric current. The main idea of getting rid of Le Grand K is that it's been around since 1889, just about 130 years. Over this long period of time, Le Grand K and it's near replicas have been observed to deteriorate, changing it's mass ever so slightly. This super small difference, about 50 parts in a billion, can make big changes and effect things like drug development, nanotechnology, and others. So, how are they going to use an electrical current to define a kilogram. Well, the plan is to use an electromagnet to create a force for our definition. As we know, the pull of the magnet relates to the current running through the solenoid, so to define the kilogram we need to find out the amount of electricity needed to counteract the mass of a kilogram.To find this balance a "super-accurate set of scales." knows as the Kibble Balance, built by DR Bryan Kibble, will be used.

I also think this is a good idea for everyone. As we found out in the article, the physical Le Grand K is something that will not work in the long run. We continue to need more accurate measurements, especially with objects made to a super small scale such as nanotechnology. By using nature instead of a man made physical object, we can feel a little more at ease as we know it will not change over the next hundred years. The kilogram isn't the only thing that will be redefined by nature as all SI units will be defined by nature in May 2019. A similar example would be the already used definition of a meter, which is the path traveled by light in 1/299 792 458 of a second. By using this instead of a physical object that slowly diminishes over a long period of time, we have something that is much more permanent. Using nature in our definition is a great idea as it will work a lot better and will remain constant a lot more permanently.