Angular Momentum - Sixty Symbols

[dragos7puri]

I suck at mechanics. :(

[MrSuperZangief]

I want the floating earth

[fritspas]

spindoctor?

[nguyentuan1990]

where can i buy that globe?

[supermanondrugs1]

Physics is the most interesting science.

[ghdr77]

@supermanondrugs1 totally agree, I'm loving it!

[wybo2]

So, if i made my wheels massless, i wouldn't be able to ballence it?

[CastFire001]

@wybo2 well it wouldnt have any momentum then

[HundredMillionViews]

2:20 george must be a graduate student

[Copernicium277]

It would have been more correct to say "not necessary for a bicycle to be stable".

[Copernicium277]

You may find this interesting:

sciencemag. org/ content/ 332/ 6027/ 339. full (It's about how the angular momentum is not the reason for a bicycle to be stable)

The article itself is not free; however, the Supporting Online Material is free and includes some videos that show the experiment:

sciencemag. org/ content/ suppl/ 2011/ 04/ 12/ 332. 6027. 339. DC1

[Koroistro]

i wonder how the force is excanged from the weel to the chair that start spinning o_o i just don't get it.

[brenoakiy]

@Koroistro there is no "force" in it...

[Koroistro]

@brenoakiy so where does the chair take the momentum from?

[brenoakiy]

@Koroistro it "acquires" angular momentum to keep the total momentum the same

if the wheel is spinning clockwise then he has to spin counterclockwise to keep that angular momentum constant

I think this is one of the hardest concepts to understand in classical mechanics...

try to think of it the same way as in linear momentum

[9493760]

ANGULAR MOMENTUM , WHAT WE'VE JUST WATCHED IS ACTUALLY A KNOWLEDGE KNOWN BY FEW PEOPLE . THESE SCIENTISTS DO A GOOD JOB OF DESCRIBING IT. IF ADAPTED TO NEW WAYS OF CREATING MOVEMENT , OR USED AS A PRIME MOVER, IT SHOULD ALWAYS BE TAKEN INTO CONSIDERATION .

GIANFRANCO FRONZI SEPTEMBER

[acs197]

I really need to get one of those suspended globe gizmos!

[badshabz1]

how is that earth levitating?

[2xsf]

@badshabz1

Turtles all the way down.

[emikochan13]

@badshabz1 magnets.

[mariakas13]

@badshabz1 it's witchcraft i tell you

[JaJani101]

@dwip57 im sure that precession is the slow movement that the wheel exhibits on its side while angular momentum is the momentum that the rotating object carries

[JaJani101]

Im spinning in my computer chair while watching this :P

[dwip57]

Bradey, I have a question for the professor about this. In Aviation, we call this 'Gyroscopic Precession' Would you be able to ask him if Angular momentum and Gyroscopic Precession are the same thing with different names or completely different?

[juraj89]

is the globe in the beginning of the video floating in mid air?

[Aviatorsmith]

@juraj89 Yep. There are magnets holding it up.

[smawshot]

In regards tot he ice dancers and most others is some technique called spotting. I don't know how they would do it while leaning back though, but alot of conditioning helps and them timing and rehearsing everything lets them know where they should be facing at a given moment.

[pagani8]

This guy is so funny and nice!

[DriedSquidHero]

I wish I had a lovely lady assistant like George.

[campainr]

I love science for teachers like this!

[metalbucket2]

I LOVE this and all your videos. I love the unpolished performances, I love the lack of flashy graphics and absence of patronising fluff. It's a sort of traditional style that's done with a modern sense of fun. All power to the fine folks at Nottingham.

[JapanForSale]

@metalbucket2 Hmm. I dunno whether this is even the right place to say this, but here goes.

Your comment is exactly why I prefer 60S over BigThink. I found both of these channels TONIGHT. They both started off on equal footings, but I just can't stand BT. It's mostly just Michi Okaku talking to hear himself talk; the audience is just there to stroke his ego. But the profs here at 60S seem like they're enthusiastically explaining what they love; there just happens to be someone recording them.

[RBIVscreamtherequiem]

@JapanForSale You're seriously jaded if you think that. Even to poke fun at Michio Kaku's name? Grow up. I've seen Kaku in many different media forms throughout the past 5 or so years and he's truly a nice person; calm, subdued, and loves to have a good laugh. He loves spreading science and knowledge and is true to the geekiest and silliest of us. I don't know what you read, or saw, but it apparently struck you the wrong way. I hope you change your mind.

[jimo1150]

So, this is how the Earth's magnetic field is created and the Compass points north!!!

[MemelsAccount]

love this guy :)

[swordfish1946]

Angular momentum = r times p (radius times mass times velocity), but the professor mentions : mass times the radius squared which is the moment of inertia indeed. Im confused. Someone could help, please? Its really an issue :)

[GODHEPME]

OMG! The globe is floating ! How do they do that ?

[bubbles02010]

oh! so this explains why i go faster when i bring my legs in while spinning in a chair!!!! physics is so exciting!

[JulesJulian7]

what is a professor when he spins?

[260830107]

WTF HACKS

[AndyKong51]

Does high current goes through a loop also create angular momentum?

If that is the case, magnet should have angular momentum too, right?

And can I change a metal object angular momentum by changing the magnetic field?

[jscook55]

So it's been a while since I've taken physics - if he had grabbed the wheel at 90 degrees but still vertically @4:27 would that have induced spinning motion? I did a little experiment on this myself - under "angular_momentum_device" jscook55's youtube channel , however I question whether this was truly angular momentum or just vibration. Any answers?

[lekunberriko1]

this professor is a crack.

[stevenrayd]

After watching this video the weighing question on my mind is the one that was ask "how do ice skaters seem unaffected from spinning" ? Good video and great presentation on angular momentum this is going to clear up alot of debate on the importance of building/customizing motorcycles in the balance issue my friends seem to trifle in this area to much and this clears it up quite well.thanks

[og882001]

profesor got sense of humor, nice!

[ViolenceFetish69]

Thats mad

[WisfulSpider]

Can you explain what is happening in this video? WCLLGqvpp7o @around the 5minute mark, there is a demonstration of a kid holding being able to hold an 18lb disk, with little effort, just because the disk is rotating- has the mass also been redistrobuted and if so where?. The video is from the controversial 1974 RI christmas lecture by Eric Laithwaite.

[anestakos83]

George to the rescue!!!!

[pbtwentythree]

.....Is that globe held up magnetically? If so.... Where can i get one?!

[aeclipseguy1]

lol I need a prof like that!

[Jaumur]

GEORGE IS AWESOME!

[c0wz]

YAY SCIENCE!!

[crystalfieldyy]

woooooo........its the BEST n d most entertaining phy vid ive EVER seen!!!!u rock,seriously!!!!

[me835]

so... what IS a professor when he spins???

[MrOldprof]

@me835 Giddy, I was very Giddy, but I have recovered now. 

[Kenoburned]

i like your accent alot lol it sounds like the accent of the scientist in half-life.......cant remember his name.

[3xxiled]

did anyone else not notice that the globe was floating at the start of the video, until it fell haha

[Likeafoxow]

didnt really explain anything:-/

just mostly demonstrated the concept.

[fuffoon]

OK, I got this back in high school physics BUT why, oh why, does the angular momentum choose to be to the right of the direction of spin? Why not to the left?

[LFZ15]

What do you call the wheel he used in his example? I want one so bad!!

[poelfkat]

SIGH IN! this made my day

nice vid, I wish of you'd would be my physics prof

[PartVIII]

i hate to pick favorites but if i had to choose, Professor Bowley takes the cake.

[MrOldprof]

@PartVIII

No, I eat the cake---see the video on Quarks. Delicious!

[MrOldprof]

@PartVIII That's why I need to lose weight after Christmas.

[tsuikjoshiomatsu]

does that wheel ever going to stop? LOL

[mrericsully]

I totally agree with Prof. Bowley, I do this demonstration in my physics class, but I always wait for the end of the period because I feel so sick and ill when I do it I cannot go on teaching. Luckily, physics is my last class of the day.

No clue how ice skaters pull off not getting dizzy.

[Rockguitarnow]

This is the technology of the future which many propulsion systems will be based on. I did extensive research into this years ago.

There are no equations yet for these actions and properties. Some scientists studying this became so fascinated, they stayed up many days straight and had a nervous breakdown, which then makes other scientists less likely to want to study it. Maybe when they understand what a nervous breakdown is and how to avoid it, we will see this new technology developed. :)

[dev00008]

That is very cool, i would never have thought that the momentum from a wheel could do things like that, i only thought that it spun and was nothing special! cool!

[kalpoo7]

Is that how gyroscopes work?!

[Fawcs]

@kalpoo7 yep

[killsourenemy]

I WANT THAT GLOBE xd. What is it called and where can I find one? ;).

[Fawcs]

@killsourenemy Try thinkgeek . com, don't know if they are overpriced or anything, but I know they have it

[jacksawild]

The dancers do it by focusing on a single point, quickly twisting their head at the moment of maximum stretch to maintain their chosen point of focus. This stops the brain from getting confused and guards against motion sickness. I am not a dancer, but martial arts can be similar. I don't mean to be rude, but fitness also plays its part. Hey, I bet not many dancers can explain angular momentum very well at all.

[itstheMAC]

Can anyone please explain to me why the wheel starts rotating in a circle at 2:45 and how conservation of ang momentum explains this? And also how would you determine beforehand in which direction it would rotate? Thanks!

[MrOldprof]

@itstheMAC Angular momentum is only conserved of there is no torque acting on the system; the wheel roitates because the tension in the string gives a force on the axle at a point which is away from the centre of mass of the wheel. Hence there is a torque and the axle of the wheel rotates, changing the direction of the angular momentum. The direction of a torque is given by a vector product; I was unable to persuade Brady that it was a suitable symbol for sixty symbols: too mathematical!

[itstheMAC]

@MrOldprof cool, thanks.

[PartVIII]

@MrOldprof The mathematics is what makes physics so elegant!

Youre not asking the viewers to solve any problems, but having a simple explanation of the mathematical background helps put somewhat abstract concepts into perspective. Mathematics gives shape to the interlocking puzzle pieces of the physical properties of nature. Mathematics helps us understand the whole picture.

Physics videos without mathematical expressions is like Chemistry videos without molecular structures.

[MrOldprof]

@PartVIII Videos of physics demonstrations (without the relevant mathematics) can engage the viewer; they can show that there are funny effects in the real world; and they give me the chance to give a physical explanation. Of course to do the job properly you need to expresses your ideas mathematically in order make rigourous predictions of what should be seen experimentally: that is the basis of the scientific method. Brady prefers me (a theoretical physicist) to do experiments badly.

[CommunityCommentary]

lol they have george and the chem guys got neil :p

[rodstartube]

lovers

[cateatingmonster86]

that was really cool! thanks

[Naddig74]

You have to make sacrifices for science...there's angular momentum in your semi-circular canals too :P Which makes me think also...how about a biology channel? You've covered chemistry and physics...you really have to round it out imo :P

[maofunkshun]

Once by accident I discovered that particular nature of the spinning bicycle wheel when doing some repairs on my bike. I didn't have the knowledge or language to explain it to myself until now. Cool stuff.

[uut0]

i once noticed this when i picked up an industrial fan when it was on :D

[arantheo]

good-humoured and excellent content,thank you

[Kitsua]

I'm absolutely loving this series of videos. Bravo and a million thanks. :-)

[Eidolon1977]

I just love Professor Bowley and his lessons!!! He's really cool. In another video he says something like "if you put a thermometer under your armpit... or elsewhere..." ;-) You guys are excellent. Keep up the good work Notts!

[unknotmiguel]

i would like to know is the author of this channel the same whos talking?

[sixtysymbols]

The videos on sixtysymbols are all filmed and edited by me (Brady) and feature various experts from the University of Nottingham.

[chrisofnottingham]

BTW Brady, you are an absolute star for making all these and walking the line between informal unscripted chat and purely educational videos.

[sixtysymbols]

@chrisofnottingham

thank you.... I'm lucky to have so many clever scientists at my disposal!!!

[kheffah]

thanks, your videos are a real treasure

[zeratul575]

i likw the magnet globe hes got there

where can i get one?

and he should go to highschool to teach this stuff his way like that he would be liked

[olympussound]

that wheel trick was cool

[iwan0t0smith]

best bit of the open day there,

spending ten minutes getting that globe to float

[JaksProductions]

dude you are really lazy editing. He says start again. and you dont care.you dont cut it out :D. cmoon leave him some dignity!

[DoomCreeper1]

I just randomly found this video and now I'm subscribing. Nice!

[sixtysymbols]

@DoomCreeper1: Glad to have you onboard...

You might also like periodicvideos, our channel about chemistry!

And nottinghamscience has all the behind the scenes stuff and other bits of science.

[DoomCreeper1]

Wow thanks!

Are you one of the men from the video? you both seem to have lots of fun

[rjhrjh3]

I am not sure that the reason we stay on a bicycle is due to angular momentum of the wheels. Otherwise it would be very hard to stay on a bicycle with small wheels. I got told it was due to the position of the rider. Cannot find any source for this information though.

Maybe you could do some experiments and then do a video. Say start with a bicycle that had zero angular momentum and see what happens.

[chrisofnottingham]

Angular momentum helps at high speed on bicycles but on mini wheel scooters at normal speed it can't really help.

What does help is our very fast steering response. If a bike starts to fall to the left we learn to steer towards the left at the same time. Steering left without leaning left actually provides a net force to the right. If you don't believe this, try turning left without leaning and you will fall to the right. Its also why we have to lean left to turn left, if we don't we fall off.

[robertwc82]

i'd like to see a unicycle go that fast lol

[Highbrowser]

To get something to move a distance, you need work (force times displacement, to simplify it). The rotational counterpart is torque. If it takes a certain force to displace something across a certain distance of turn (something we measure in radians), when we shorten the distance, we put more force into a shorter movement. Which means it accelerates more.

[MichaelKingsfordGray]

I didn't catch where he claimed that, but:

m.r^2 is the "moment of inertia".

Angular momentum is this times the angular velocity.

[wildwolf111]

This is why helicopters need a small rotor on its tail.

[ricardjorg]

if you think of it, the rotor on the tail of the helicopter could be horizontal instead of vertical, and it would do the same as the spinning professor on the chair and rotate the heli

[samopollo]

The second one.

[nawitus]

Yes, and in fact the rotor on the tail of the helicopter was designed to prevent the helicopter itself from rotation. This same thing created problems with World War 1 fighter planes, the planes turned well only in one direction..

[saemj]

iceskaters do it by looking at a fix point at their body, so it seems to them as if they are not spinning at all.

[insAneTunA]

hehehehe that was a lot of physical action for a professor. I even thought for a moment that I heard a woman screaming for help. 4:47

Other then that it is a great video :-)

Greets, iT

[777Marlene]

aww shoot ...George didnt spin him fast enough, i wanted to see him display more magnetic attraction

[iwan0t0smith]

actually it's not entirely impossible to stay still on a unicycle, it's just verry difficult

[comface]

Look up chris holm, champion unicyclist. He is able to balance on one wheel for as long as he wants... even with a sheer drop on one side!

[iwan0t0smith]

That's who i was refering to,

mind boggling what these people can do

[Paxmax]

funny and mildly educational!

[Mattybloke]

lol at george

[kativilaga]

Very cool editing Gready!

I like how you leave the funny random things in there!

I do it too when I make editings for people but I've never seen someone else doing it (one of the things I do for living), and it makes me realise that it's very nice because it makes the result very lifelike!!!

[culwin]

Angular Momentum blows my mind

[brilliantfranz]

he's like the phisycs version of prof. Martyn Poliakoff

cooool man !

[BYMYSYD]

you need more roller coaster experience.

[exodus2142]

i like how he has a slave

[kbcbcofme]

never knew this exist

[Keimori12]

in the start, whats keeping the globe afloat? magnitisim? or did he rethread some form of fishline?

[whitehiliter]

Looks like magnetism.

[gayglue]

Magnetism :)

[jacoman1234567]

Very cool and amazing explanation of the angular momentum, especially the litte 'experiments' done are fascinating !

[wvb93]

angular mentum D:

[oisiaa]

Great demonstration of how reaction wheels work to control the orientation of satellites.

[DeoMachina]

Where would the world be without George

[gulllars]

Another place where angular momentum is really important is breakdancing. Almost all the tricks where you are rotating continuisly are dependent on working with the rotation and not against it and feeding the momentum faster than the friction can decreese it.

[MewHamHead]

Great presentation!

[SMFApples]

I really liked this one

[ReallyPsilly]

What a neat presentation!

[solomsolomol]

easy George , we only got one prof. Bowley and we don't want to break him : )

[HansTheAtheist]

I haven't seen any video about the symbol 't' yet, if you're looking for ideas.

[PartVIII]

i want a professor like you!

[Danthaman1971]

One question, why does the angular momentum "want" to stay perpendicular to the direction of gravitation, or doesn't it?...

[yellowlabrador]

Love you all suffering in the name of science

[OhYeahMilkIt]

this professor is quite weak... we need to have some physical training for physics professors here at Nottingham!

[sporkafife]

Teehee, is this what you spend all your time doing? Trying to make professors ill.

[labrat882]

Ahaha, spinning professors for sciense! He was really adorable, tho. I feel like I'm back in school in those fun classes, everyone on these videos are so charismatic and excited about what they do.

[Doogeedoo12]

Hahaha, oh dear. That poor man. I empathize with him. If I turn around 360 really fast, that's all it takes for me to get dizzy.

Got to love angular momentum!!

[RookieStudios]

ya make a video about George, that would be neat!

[sixtysymbols]

@RookieStudios: I'll see if I can talk George into it...

[theiamania]

Love the videos, but this one had to much "how" and not enough "why". Still didn't find the explanation of why you spin faster when centering the mass. My best guess is that it is because the mass wants to keep the same speed, and because the circle is shorter when centering, then you spin faster.

[WisseSpring]

I'm not sure why prof. said angular momentum equals m times r^2, because the formula I know contains mass, velocity and radius. So if you take this (L=m*v*r) you can see that if radius gets smaller speed needs to get higher in order to conserve angular momentum.

[itsabomberscope]

Fantastic video. Can you please do a video about George (if he wants to of course). He is always there, but we dont get to see what he really does. Cheers.

[CaptainSpaktastic]

If I remember my first year labs - George's job is to explain the experiments once the students have read the lab manual not not understood a word of it. I would probably have failed the year if it wasn't for George. Thanks George, if you read this!

You should film one of Prof Bowley's lectures, they are an interesting experience.

[itsabomberscope]

Thanks for the info. We want george! lol

[callishka]

@itsabomberscope I'm with you. I want an interview with George!

[RupertsCrystals]

I sympathise with him. I get car sick in small cars.

When I was about six my aunt wanted to take us for a spin in her new mini. We piled into the car, she pulled out from the kerb and moved about three car lengths down the road and...

Oh dear. All over hew new shoes. :-(

[avecesdeunhilo]

you misspelled "physics" in the video info.

It says More phsyics at.....

loved the dizzy Professor

[sixtysymbols]

@avecesdeunhilo: Thanks... Always prefer having typos pointed out in things I can actually fix, rather than finished videos! :)

[Chipsonfire]

I always had a problem understanding angular momentum, but this is a very good explanation.

[Woad25]

Don't worry, nobody really knows what exactly angular momentum is. There was a joke in my grad school that went "If you're ever asked a question during a presentation that you don't know how to answer, just say the answer is angular momentum. Since nobody understands it, nobody will really press the issue."

[Chipsonfire]

lol That makes me feel better :-)

[seanbrockest]

I know how he feels, the slightest bit of spinning is enough to set me off too. i hate it.