The kg is dead, long live the kg Electromagnetic Levitation Quadcopter 2 months ago   09:58

The kilogram, mole, kelvin, and ampere will be redefined by physical constants. For a limited time, get 3 months of Audible for just $6.95 a month: or text VERITASIUM to 500500

Will this be the last video I make about SI units? Quite possibly. There's something about being so precise and defining the systems within which science works. When we can more accurately and routinely measure a kilogram, a mole, a kelvin and an ampere, then we can make better observations, we can better detect anomalies and improve our theories. That is why this is so important to me.

Special thanks to Patreon supporters:
Donal Botkin, Michael Krugman, Ron Neal, Nathan Hansen, James M Nicholson, Terrance Shepherd, Stan Presolski

Special thanks to NIST:

Additional graphics by Ignat Berbeci

Music from "Experimental1"

Comments 6387 Comments

DT Undercover
Why not start with the smallest unit of measurement and simply extrapolate from there... take the atomic weight of... hydrogen and go from there... or carbon...
Aldsy Irgg
And I studied the definition of kilogram in August 2018! When everything was still based on that block! I only got to know this today, 2 months after the transition was complete..... Wow.... The definition of something so fundamental I knew last summer has been changed, that is so exciting
Hey NIST, if you guys don't need K4 and K20 anymore, I'd be willing to take it off your hands.
Ya know, for posterity ^.^
Press F for little Jimmy Please
Treaty of Versailles 2: Electric Boogaloo
Lune Vermeil
STEAM>>STEM I honestly couldn't see science the same without those beautiful observations that I simply can't rationalize, rather intuit. Once I do that I can work my way back to the answers.

My math teachers hated I had the answers but didn't know how to show the work. Now that I'm older I do understand the importance of checking your work.

Some of the hardest problems I've found and answer and had to work back to the question.

My whole life..
Aww So cute
Rest in pieces kilogram.
Its been 7 months and I didnt know this
Prince Zåkãrï Loewen
my head hurts. :P so many big words.
Reed Bowman
I'd really love to see a video on ground-up definitions of all units from the basics. Mass of a proton, charge of an electron, etc, and see what the human-scale metric system would look like built that way. I'm sure there are people out there who have proposed such systems.
Tamago Eggo
Avocado’s constant heheh
Rasmon 123
What you snack about?
The Kg is not dead
Daniel Reyes
I dont even know why im excited for this
2:40 Enderman ???
In a 100 years, we'll laugh at ourselves for using unstable pleb constants derived from matter instead of the length of some hyperdimensional electron spacetime folding mechanism.
Sanny Devito Oof
I like to watch this while playing Minecraft
Robert Kamminga
What weight 1 gram from now, when they change it
Elektra Pedersen
Will this complicate my homework or make it easier. Becuz if this is gonna give me harder math I don’t want it
Max Torfs
Doesn't this mean everything that has the kg in the formula is a lie?
Doesn't that mean that the definition of a meter changed slightly too? There is a relation between the two after all.
Nathan Bainbridge
"We are wresting some sort of order out of the chaos that is our universe."

There is no chaos.
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Electromagnetic Levitation Quadcopter The kg is dead, long live the kg 2 months ago   06:19

Spinning magnets near copper sheets create levitation!
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Special thanks to Hyperloop One for showing me around.

Thanks to Patreon supporters:
Nathan Hansen, Donal Botkin, Tony Fadell, Saeed Alghamdi, Zach Mueller, Ron Neal, Perry cl, Bryan Baker
Support Veritasium on Patreon:

Filmed by Raquel Nuno, Edited by Trevor Carlee

Obviously this "quadcopter" is a demonstration device, showing how moving magnets over a conducting surface can generate levitation. It has not been optimized to minimize losses or be an efficient mode of transport. I still think it's pretty cool. I'm used to seeing light things levitated by induced currents but not a 100+ lb machine.

For more on Hyperloop One: