Tom Scott Reveals That Nobody Is Exactly Sure How Much a Kilogram Weighs Right Now

In an episode of his Things You Might Not Know series, Tom Scott revealed that nobody is exactly sure how much a kilogram weighs right now. That’s because the system used to measure things internationally is based on a physical standard, but as Scott explains, scientists are working towards a better and more absolute solution.

Yes, it’s only micrograms of difference, but it’s still really weird: until 2018, the kilogram is defined as “the weight of this physical object”. So what happens when that object changes?