How We're Redefining the kg on HackerTube: recommended by 3 Hacker News commenters across 3 separate months, 2017–2024.
explainer · evergreen
Veritasium explains why the kilogram is being redefined in terms of Planck's constant rather than a physical metal artifact. It visits NIST to show the Kibble balance and why measuring mass precisely is hard.
Praised as an excellent, accessible account of why the kilogram's definition changed, in redefinition threads.
“I found the Veritasium video to be a bit more interesting for the "why" aspect of this change”
3 Hacker News comments link this video. Each one links back to its thread.
Veritasium (Derick, who I've met personally) does a fantastic job on these fundamental science subjects. Le Grande K was the definition of the kilogram. Derick explains the question at hand, how Plancks constant is now used. Derick's quality is supreme & he is always very careful and confident about claims. ▶ this video
in “Le Grand K (2018)” · View on HN
There's also an excellent video from Veritasium, a science and education YouTube channel, about what's being done to define the kilogram ▶ this video
in “Redefining the Kilogram” · View on HN
> Does anyone have an example of where a change like this would be important? Well, it's important today, because the reference samples used across the world have drifted apart, and not in a consistent fashion. Which raises the question of whether the exemplar kg has drifted as well. So, we don't really know if the kg we're using today is the same kg we were using 10 years ago. Given how important mass is to many scientific calculations, a drifting standard could directly impact all the other work we do. I found the Veritasium video to be a bit more interesting for the "why" aspect of this change: ▶ this video
in “Why scientists are redefining the kilogram” · View on HN