Redefining the Kilogram with the DIY Watt Balance

Mass is a challenging concept to tie down, yet it is one of the most crucial measurements in our world. Since the 1800's, we've used a physical artifact as a standard for mass calibration across the world. Within the next few years, that will all change because of this ingenious device: the watt balance.
Links:
-NIST Lego Watt Balance Paper: scitation.aip.org/content/aapt...
-NIST Lego Watt Balance Video: • How to Build Your NIST...
-Building the Desktop Watt Balance: [Coming soon!]
-Watt Balance Technical Drawing Timelapse: • Technical Illustration...
Watch this video and the entire Practical Engineering catalog ad-free on Nebula: go.nebula.tv/practical-engine...
-Patreon: / practicalengineering
-Website: practical.engineering
-Music: Elexive - Tonic and Energy ( • Elexive - Tonic and En... )
This video is sponsored by The Great Courses Plus.

[@NuclearStr1der]

That technical drawing was incredible to watch.

[@tzq33tdq]

That drawing at the start... Was beautiful...

[@nickp1987]

So I haven't seen anyone else comment on this, but you appear to be a pretty good draftsman. That drawing came out looking nice.

[@PracticalEngineeringChannel]

Thanks! I've been practicing.

[@atrumblood]

It has always amazed me how well diagrams were drawn in old documents. These days it is all done on computers. yours is amazing.

[@lucasburson7984]

Have you ever taken a drafting class by hand? I am in the process of getting an engineering degree and we don't even take computer drafting; all our computer drawing is 3d modeling.

[@pangpengmaster]

That drawing is better than my Solidwork assignment.

[@jxh02]

Hey, French and Vierck! I have a whole collection of those, in numerous editions.

[@robpetersen6584]

As a retired metrologist who ran the "Mechanical/Physical" lab at Boeing in Seattle until my retirement, I no longer have my fingers in the science involved in metrology. I know that the issues you describe about the kilogram being the only primary standard not based on a natural constant, has been a topic of concern for a very long time, so this is truly a exciting development. Thanks for another great video.

[@ExtantFrodo2]

I like the image at 9:27 showing the Watt Balance at the NIST. Notable is the use of a disk instead of a rod in order to maintain truly constant balance throughout the "swing".

[@ThisOldTony]

excellent!

[@PracticalEngineeringChannel]

Thanks man!

[@joe-edward]

This is a great video! I know it's a bit older than your current content, but I love this type of science, and you teach it well. Thank you for creating!

[@Prozwolfx]

As a Year 12 (Senior (?) year) student studying both Physics and (Systems) Engineering, this puts into perspective a lot of what I've learnt over the last year or so doing Physics. I was blown away by the application of electromagnetism in measuring mass - something I've learnt only a few months ago. This video is awesome, kudos to you, Grady! Your video just made my day :D

[@GauravA42]

Nice video Grady! Weirdly enough I really enjoyed your intro where you are drawing your design. I study engineering but have never touched any drafting tools, as it is obsolete these days, but watching you bring your design to life on paper, (and then in real life), with your hands looks so damn satisfying, I might have to try it some day. CAD just isnt as personal!

[@stanmccorkle]

I’ve been a subscriber for years, but have only ever watched the next new video. I am enjoying binge watching your channel. This particular video was so packed so full of interesting info that I will have to watch it again before I move on to the next one. I’m grateful you are willing to share your talents with the world.

[@StefanGotteswinter]

Just listened to the common engineers episode you where featured - Completely missed this video about the watt balance, very interesting!

[@KoalaKrisp1]

The quality of your videos are stunning. Its amazing how you manage to create such great demonstration props while also balancing a full time engineering job. I aspire to be like you after I graduate :)

[@pcfreak1992]

These videos are getting better and better! I really enjoyed this one, especially because it is explaining something relevant that you didn't see on 100 other channels already. Keep it up!

[@RoySchl]

i think that is the first time i see labview in a youtube video hehe

[@fohdeesha]

lol same. leave it to Grady

[@JustinDrentlaw]

I used LabView back in high school. Haven't seen or used it since lol.

[@dazzershell]

Nato Railgun prototype control room was operated by Labview, i remember that big indicators and Fire button)

[@Cyberguy42]

Labview... That takes me back

[@BushCampingTools]

It's a great video and as u say good to show even the "semi failures". BTW love the art in the backgrounds of these vids! I spent years doing electrophysiology and it's a never ending battle to remove noise from real signals, so for your demo here, it was pretty damn good!

[@CapturePlay]

Another great video Grady! I've seen some other videos on this topic, but I think you did a fantastic job running through it at just the right pace and detail. Keep em coming!

[@landonkryger]

Wow. I always heard that watt balances were super expensive. That must have been only talking about the super high precision ones. I never imagined that you could build one at home.

[@casacara]

With the level of precision desired for the kilogram redefinition, I imagine it had to be made incredibly sensitive and accurate, so the level of engineering complexity was likely high, and part specification tolerance was low.

[@96tomms123]

Im surprised by your drawing skills, its just amazing!

[@leopoldarkham7017]

You and TPAI are my favorite channels for making complex things sound simple. Keep it up it's really awesome!

[@rklauco]

I think your videos are getting better and better. Engaging, entraining and, most importantly, more educational. Thanks!

[@petarbul]

the quality of this video is just amazing for one man operation

[@JackmanWorks]

awesome! glad you're picking up sponsors 👍👍

[@jmlundy1]

I am a CivE/Structural and have just 'found' you via a recommendation from my son (an M.E.) and if this video is any indication, I will enjoy the rest of your offerings!

[@taschke1221]

Thx so much for your advocacy. You're doing great work to give a fair shake to those less fortunate.

[@blockchaaain]

Next video: How high-precision gravity measuring devices work ?

[@dazzershell]

Anchor and ballistic gravimeter. First is too simple, second is too complex. It would require interferometer with stabilised wavelength HeNe laser, and most hard part to made - probe unit thrower. Probe must flying in vacuum tube without any rotation or tilt, also it must have prismatic reflector for interferometer work. Computing is the easyest part). Our gravimeter was mounted on Ural military truck.

[@GadgetBoy]

Watching the timelapse of you doing those technical drawings is somewhat mesmerizing.

[@GodlikeIridium]

Nobody known or heard about this, but it's one of the most important scientific discoveries of the century! And it's so easy...

[@jeffreybooty7690]

BY FAR my favorite video of yours .... so far anyway.... Keep doing this level of work, if you will please.

[@martinrosen9742]

found you via a colleague, very well done videos. I will tell teachers to show your videos in classrooms!

[@NeilvanGeffen]

This video was fantastic, and a great way to start the day :) Thanks Grady! Keep 'em coming!

[@AxcelleratorT]

Great video!!! I've been messing around with astatic galvanometers and suspended coil mirror galvanometers for a few years so this project was right up my alley. Thumbs up!

[@shanegarstig9689]

I have been watching for some time and finally subscribed, in part because I love that you glue googly eyes on your stuff

[@beliasphyre3497]

Awesome! I work closely with the quality assurance department in my job as a mechanical engineer technician, so I know how important accurate measurement is. One percent error on a device built in a garage is impressive. I especially like the googly eyes, they always bring that extra something to a project.

[@fennercolson8680]

great work as always man. keep up the good work, it's much appreciated

[@robertt5992]

What people don't realize is just about everything goes across a scale one way or another.Brilliant explanation. I've been in the scale industry since 1984 dealing with scales that had an accuracy of a nanogram to the largest capacity of 10,000,000 lbs and have always referred to the French 1Kg weight when explaining to customers how accurate their scales are and certification of weights. Now technology has changed that. Thank you for taking the time.

[@scott98390]

Great video, great demonstration - great all around!

[@Conservator.]

First time the now definitive intro tune is played. 🤓 (That tune has become an integral part of Grady’s videos and it always plays in head just before it starts in a video 😁)

[@whatthefunction9140]

damn! you scienced the shit out of that!

[@rlewis1946]

And he showed it using some basic Algebra, too! R

[@theomnipresent1]

Yeah, Science Bitch!!!

[@SuperGamingeek]

Amazing video as usual, nice work Grady.

[@ger128]

Really great video. I had to watch it several times, but by the end I felt like I actually learned something new!

[@gaius_enceladus]

*Excellent* video and a *great* model! This is the kind of model that really gives a good feel for the new definition!

[@oldjd7745]

This is a true example of applying what is known about nature to expand our knowledge of nature. It shows the beauty of the human mind.

[@LadyTink]

The great courses plus plug at the end was actually very well done. Dozens of channels I watch have mentioned it, but I tend to click away from the video the second the video went into advert mode. I think the odd camera angle and the clips from a lecture series from great courses really got my attention. Figured I'd share this since I clicked the link :P

[@taijuonfire]

These are getting really good! Well done sir.

[@patrickpolizzi7]

I discovered your channel week before last, I think. I am a nurse. I love science, and before nursing, I wanted to become an engineer. Thus my interest in your channel. As of last night and today I have been binge watching your channel. I have enjoyed all of the videos. I think my favorite was the episode in which you reinforced gravel with bolts (Why tunnels don't collapse). Up until this episode everything was extremely cool. However, after watching this video, all I can say is wow. This one this one really satiated my curiosity niggle. It was very enjoyable and extremely cool. Thank you for all of the work you put into making these videos.

[@ChristopherBrandsdal]

Insane! I just love your work! Yet another great video.

[@TheMarcball]

Fantastic, I greatly enjoyed it and will be pondering the significance on and off over the coming days. Well done ! Keep on trucking ! (from France)

[@JorgeJimenez2020]

Awesome video and you have done a great job explaining all the theory! Subscribed!

[@enordentoft]

For non-engineering, non-science, and just generally everyday use, in countries using the metric system we usually just correlate a kilo to ~ 1 liter of water.

[@danielhawkins3392]

they have done something very similar with a sphere made of silicon(I believe). silicon was used as the structure is most well researched and understood. its the roundest object on earth!

[@Ikkarson]

you mean at 4 degrees Celsius? or even at 277,15 K? that would seem more accurate for a metrologist ;-)

[@marianoaldogaston]

yes that it is true. the problem with this as definition is that 1 liter of water have a mass of 1 kg. at 4 c. but at one atmosphere of pressure. and for the pressure definition you need the kilogram.

[@ESSBrew]

yeah, but a liter of water is based off a kilogram. So you are doing the conversion backwards.

[@maaskeimorgen]

but the volume of a fluid doesn't vary with pressure now does it?

[@kianakim1]

Great video as always! You always have such high quality demos with an easy to understand explanations. Also, googly eyes!

[@Cactusworkshopchannel]

Fantastic as always!

[@MichaelNatrin]

This is really really cool. Thanks for sharing.

[@ddegn]

I second the suggestion from +Don Donlee about moving the wired components off of the balance beam. I'm a chemist myself and I have a very precise balance but it's really hard to get accurate measurements do to static electricity. One trick I've learned is to use static dissipation or conducting materials. You probably want to use materials which don't hold static charges well when you get around to building your next version. You probably already know this, but when using mirrors with lasers, it's a good idea to use "first surface" mirrors so you don't get a double reflection from the glass. Thanks for another great video!

[@DTZinatbakhsh]

Today, this taught me something pretty neat. It also taught me that balances can be adorable. Keep up the fancy videos.

[@joshajohnson]

Another great video Grady, can't wait for the next one!

[@ExCoSeH]

Very informative video. Really enjoyed watching it.

[@Doping1234]

Thank you, very illustrative demonstration! I've heard of the Watt balance quite a few times but it was never explained. I would have liked to hear some discussion as to what the accuracy limiting factors might be/why the professional watt balance looks differently to yours - I think this would have rounded off the experiment. Anyways, can't wait for your next project :)

[@sebsunda]

Amazing video!! Thanks a lot!

[@johnSmith-ke5il]

very well produced Video and very interesting and important topic

[@lulzmachineify]

Your cat was chewing your toothbrush in the end. Just so you know 😛

[@PracticalEngineeringChannel]

That one was retired long ago

[@taschke1221]

lulzmachineify that's the cats toothbrush. He was just doing what most humans struggle with because he lives with a genius.

[@exetercollegeuktechnologyc1323]

This is really brilliant - I intend to show it to all my pre-university and university level students here at the Technology Centre - very many thanks

[@TheDawidh15]

Awesome! Thanks for this video

[@Pillowcase]

Fantastic! thanks for making this

[@gaius_enceladus]

Awwwwww...... nice cat at the end!

[@GlennHamblin]

Super video dude. I'm soo subscribed!

[@Tom_____5]

What a great video man. So interesting

[@randystuart1196]

ingenious! Thank you for sharing.

[@Ditrix88]

amazing work!

[@rayg5445]

I just saw this in a Science magazine stating "Le Grand K could be facing retirement." It's awesome to see this video since I left the waiting room a few paragraphs in.

[@stan820624]

Great work!

[@JustOneAsbesto]

Time to get a new toothbrush, Grady.

[@PracticalEngineeringChannel]

+JustOneAsbesto Haha that one was retired long ago.

[@InorganicVegan]

Grady, this was awesome! Liked!

[@SammSheperd]

That was beautiful

[@PracticalEngineeringChannel]

Thanks Samm!

[@brainfornothing]

I read this in the day, but I never understand it very well, until now. Thanks for sharing !

[@jeremyindenver]

Excellent video!

[@rorabr]

Awesome! Thank you!

[@ComandanteJ]

Top quality, as always.

[@JanWey91]

The animation was amazing!

[@romeokilo125]

thank you for this one. I read an article about this but definitely didn't understand it as well as I do now.

[@ormendel1]

Simply awesome!!!

[@Borskey]

I hope you aren't salty about the "Fail of the Week" thing -- your video was excellent, and very educational -- even though you didn't get the results you were hoping for. In fact, the fact that you showed that, honestly, and didn't sugar coat your results is precisely WHY your video was so good and educational. That makes it worth MORE than a 'everything worked fine' type of video -- and it seems that is part of what the 'Fail of the Week' is for. (And, speaking of such things, I would love to see data on how accurate your home made Watt balance is)

[@PracticalEngineeringChannel]

Haha definitely not. I was happy to be featured, and that's really the spirit of the "fail of the week": that we learn through our shortcomings and mistakes.

[@Strothy2]

instant sub man! great video!

[@adwaitbhandari1042]

Wow nice video man

[@MethodicalMaker]

Love the videos, The time you put into your animations and drawings are mind blowing. Could you perhaps do a follow up video covering some of the other proposed kilogram replacements? such as the international avogadeo project?

[@ThePiquedPigeon]

I've missed the first seconds of the video showing Grady sketching that drawing at 0:38, and when I saw it I though it was one of those ornate patent drawings from the late 1800s. Grady is really a classy drafter!!

[@kenmore01]

Okay, that's pretty cool. It's also pretty cool that you didn't burn the place down. 😃

[@jimmygee5]

Amazing video

[@_BangDroid_]

Great Video!

[@dyzoly]

This is truly huge!

[@jasonsilver5339]

@Practical Engineering, I found this very interesting and was the first time I have heard of this method for defining the kilogram. Last I had heard was that we are trying to define the kilogram based on a particular number of silicon atoms. "Veritasium - Worlds Roundest Object" is a good video on this.

[@MrRishik123]

10:02 Ohh i thought it was sponsored by the cat

[@hafidyadis1134]

amazing work! keep it up;)

[@deadmeatdec2164]

I have seen like a dozen of your videos sir and what you call the juxtaposition of natural materials in your precision instrument I call you have cool boy toys and like playing with them.

[@Alderkail]

Your videos are great

[@alexanderschwagerl9201]

Looks like your are using the NIST-Labview Software :) You might be glad to hear that the new python based software is almost done and even better. I'm on it!

[@PracticalEngineeringChannel]

Sweet! Are you at NIST? Huge thanks to you and your colleagues for making the science more accessible to dummies like me!

[@alexanderschwagerl9201]

Yes! I am there for an internship and got to work with the awesome team which created this project and the even more awesome actual NIST4 Wattbalance.

[@CyborgPandaBaby]

This was actually really cool

[@Upsidedownorangejuice]

This video was really really good

[@artjones2498]

hey i know this is a old vid....but i really like it and your wood working skills are sharp your watt balance tool looks cool.....makes me wish i paid more attention in electronics in school

[@paola3844]

Genial, muchas gracias.

[@lachlanC50]

i also love that if they adopt this, a key day to day useful measurements bare roots can be taught and discussed by a classroom science experiment

[@sabbib007madness]

You are amazing :D you need more exposure