The Mystery of Rattlebacks

Rattle backs used to be regarded as mystical stones, but Rob reveals why they behave as they do and even how you can make your own out of everyday materials around the house.

[@quiesty99]

I've just discovered these videos. There goes the next 6 hours of my life.....

[@CuriosityShow]

Thanks. Curiosity Show was a national science program for children featuring Dr Rob Morrison and Dr Deane Hutton. It was made in Adelaide, South Australia and screened nationally in Australia as well as in Europe, Asia and Australasia (14 countries) from 1972-1990. Deane and Rob intentionally used everyday items around the house (like old cans) so that children could repeat the demonstrations with materials they had to hand. In 1984 Curiosity Show won the Prix Jeunesse International, the world's top award for children's TV programs. Rob and Deane are steadily uploading segments at kzbin.info Why not subscribe?

[@quiesty99]

What were they doctors of? Engineering? The range of topics is fantastic!

[@Ste_Brit]

I only discovered these within the last month 😂 I was an 80’s kid but don’t remember seeing this in the UK 🤔

[@myself3209]

Well invested time

[@myself_rishi]

@@Ste_Brit ha lol me too

[@briansewart5885]

One of the best things ever to be produced in my home town. We would actually make a lot of the stuff in the shows. The best part was everything worked as described. Very rewarding for kids.. remember we had none of the distractions of today, so these things were great for us :)

[@CuriosityShow]

Very kind. We always showed our 'make and do' things working on air. Kids would then know that they DID work if they got them right and not expect them to do more than ours did - Rob

[@alexjames1146]

I wish I'd lifted the science master's car after the levers episode. I used to watch the show every weekend. Why is it so was during the week after school with Julius Sumner Miller. Life in the seventies in Sydney.

[@briansewart5885]

@@alexjames1146 "A glass and a hulf in every 200 gram Block!"

[@Broockle]

Curiosity Show aired 1972 to 1990 ye that checks out

[@zaryabmomin7244]

really love the way dean and rob presented every topic i really want to see them on the channel together like old rob and old dean together

[@CuriosityShow]

Very kind of you - we still do live shows together - one in Melbourne with the Symphony Orchestra coming up on August 18 - Rob

[@deanmoncaster]

I don't remember presenting this show

[@cristytayhan1195]

I love old education videos like this, they have a real, genuine wholesome quality to them

[@Flippin-mad]

I'd like to thank this show (the original writers) for opening my eyes and giving me the desire to be me. My life was shaped by this show. Thank you.

[@CuriosityShow]

Our pleasure - Rob

[@cristytayhan1195]

Warms the heart to read comments like this ♥️

[@majorskepticism7836]

I examined the contour of a plastic rattleback on a shadowgraph. It kinda looked like there was a curve in places similar to the top of an airplane wing. This was cross sections of the short axis.

[@Ghostsoulless]

My parents had an old set of silverware growing up, and I would always spin a knife on the counter and it did just this. Always thought it was interesting but never gave it much thought. Cool to see a bit how it works (and learning more detailed explanations in the comments).

[@philward141]

Such a great show. Between this and Match Mates, my afternoons were made. Thank you for being pat of my childhood in the 80's.

[@markmark2080]

Thank you for this video, now when looking at stones in a creek, there's something more to be aware of.

[@bobdown8043]

You could do a whole episode on Rob’s jumper.

[@CuriosityShow]

Thanks. Have a look at Deane's shirts! Curiosity Show was a national science program for children featuring Dr Rob Morrison and Dr Deane Hutton. It was made in Adelaide, South Australia+ and screened nationally in Australia as well as in Europe, Asia and Australasia (14 countries) from 1972-1990. Deane and Rob intentionally used everyday items around the house (like old cans) so that children could repeat the demonstrations with materials they had to hand. In 1984 Curiosity Show won the Prix Jeunesse International,the world's top award for children's TV programs. Rob and Deane are steadily uploading segments at kzbin.info Why not subscribe?

[@deafmusician2]

I don't do much jumping at my job but if required to do so, I shall be suitably attired!

[@bobdown8043]

@@deafmusician2 Sweater to you guys?

[@deafmusician2]

@@bobdown8043 and here, I've been jumping around with them asking the sales weasel "what do you think?"

[@AllenKnutson]

When I'm teaching multivariable calculus, which involves computing second derivatives and Hessians and so forth, I point out that the two principal axes of curvature at a point on a surface are necessarily orthogonal to one another. And then I show off my rattleback (plastic, from a museum gift shop). It's well explained here that the rattleback property is exactly about those axes being misaligned with the obvious axes of the object.

[@randominternetguy3537]

Can you describe what makes this phenomenon occur? I understand why it becomes unstable, but spinning backwards seems really counterintuitive

[@TheBetaMale]

My guess is stored momentum and the energy continues in the opposite direction. Notice how it doesn't last long just a few seconds

[@davegoldspink5354]

Unbelievable well this really takes me back. I absolutely loved the curiosity show as a kid back in the 70s. Thanks for sharing this.

[@kurzackd]

he forgot to mention the most important and interesting part: If you spin such objects THE OTHER WAY, they'll spin NORMALLY !!! (i.e. they won't start to wobble and turn around !)

[@darren8269]

At 3:48 he said that. "Trial and error will tell you which way." Ergo, spin it the other way, it will not rattle back. He might not have thought that is the most "interesting part", nor do I.

[@madwhitehare3635]

@@darren8269 Hair on, Darren….

[@AllenKnutson]

This omission bothered me a great deal!

[@brianlee5702]

My childhood was taken up with "Why Is It So" which is where I got my true love of science but I've only discovered the Curiosity Show this week and it got to wondering how I came to miss such a marvellous production. A comment below tells me it started in 1972 which is just when I discovered girls so it hardly takes a scientist to explain things further. Equally, I have grandchildren now who'll get a lot of joy from it so will certainly be passing on the links. Sincere thanks to all concerned.

[@Krztph1331]

What fantastic presentation. Very well produced.

[@BernardWilkinson]

It bothers me somewhat that these simple, cheap but really informative programmes are not being shown on terestrial television nowadays. This is a good example. Another good example was Johny Balls - Think of a Number produced by the BBC in the 1980's. Brilliant stuff.

[@cybersentient4758]

I'm sorry but, Johny Balls 😂

[@bugler75]

@@cybersentient4758 Johnny Ball, singular, he was monorchism 😁. His daughter Zoe is a well known presenter/DJ on BBC Radio.

[@cybersentient4758]

@@bugler75 man he's seems a cool guy from what I've seen, but I bet he was bullied at some point for his name lol

[@bugler75]

@@cybersentient4758 I maybe came across as rude! Sorry! I loved his programme when I was a youngster and I certainly had a snigger at his name. I learnt a lot from his series and I’m going to look it up 😁👍🏼 Have a nice evening, day! Ian

[@cybersentient4758]

@@bugler75 damn you're polite man, not rude I didnt know anything abt John until now I'm a young dude so thanks

[@kenincairns9025]

Best show ever. Loved it as a kid, and its competitor on the ABC. Wish the kids had something like it today.

[@Graknorke]

Ha, this brings me back to my university entrance interview, I was given a question on how I thought rattlebacks work. Had never seen one in my life and never actually worked it out during the interview either.

[@MrTweetyhack]

do you have an answer now?

[@3glitch9]

Hogwarts?

[@jasonjase8661]

This guy is awesome. He is very clear and knowledgeable. It is like here is some random thing I thought about researched, applied and how you can play with it. Great for adults not just kids.

[@CuriosityShow]

Thanks, that was the idea - Rob

[@polygonalmasonary]

This video doesn't explain the 'Physics' behind these objects. The laws of Physics say an object will travel in one direction until an outside force acts upon it. HOW do 'Rattlebacks' spin the other way without causing the accepted laws to be proved incorrect? PS: You can now buy mass produced 'Rattlebacks' made out of heavy plastic!

[@entelechy777]

@@polygonalmasonary I think it would have to do with the geometry and balance of the rattleback. So it spins so far in one direction and then the imbalance causes it to basically get pulled back by the offset weight. Thus it doesn't violate physics because an outside force - gravity - is acting upon it.

[@DrTWG]

These shows are gold - I wonder how many were inspired to follow a career in science . The presentation is great .

[@williampremo2197]

Being from the states, I can say that I wish we had more shows like this. Kids need to explore their curiosity.

[@Notacladist]

"The Mystery of Rattlebacks" remains a mystery. (The instability seems to be key somehow). Part 2 on the way?

[@mulgerbill]

Part two is unlikely as that was filmed in the 70s. Here you go kzbin.info/www/bejne/bGq7nmpsZ9Z4btE

[@christophersavignon4191]

It's the "curiosity show". Big emphasis on "curiosity". They only show you things that pike your curiosity, but don't explain the trick. Finding out why these things do what they do is up to you.

[@christophersavignon4191]

@Joker Toker There's a lot going on there. Spoiler Warning... For one, the center of gravity is above the center of geometry. That way it starts to tilt and teeter. When it teeters, the contact point is no longer in the center, but spins around the center. The diferent angles of the contact points force the stone to transfer energy from the spin into a back and forth tilt (lengthwise), and recover it to the spin from a sideways tilt (short... shortwise?). The weight is distributed in an elongated manner, so it tilts sideways with little energy, and back and forth with more energy. That way, the back and forth tilt drains more energy than the sidewards tilt returns. The tilting increases until at some point it stops spinning. The tilt pushes the stone onto the table, and the angle of the contact points transfer that energy into a reverse spinning motion. The reason it spins freely in reverse is simple: the reverse spin creates a sidewards tilt, which consumes less energy and returns it quickly. Any back and forth tilt quickly returns its energy to the spin due to the angle of the contact points. To put it weirdly, the stone spins uphill in one direction and downhill in the other.

[@christophersavignon4191]

@aboctok Haha, I knew I had it wrong. Damn. That's what you get when you're too lazy to look it up and just guess. Although, isn't pique just derived from the french word for pike?(actually from piquer, pricking/piercing, just looked it up. Pike and pique share the same etymological roots)

[@eidolor]

On a similar note kzbin.info/www/bejne/rZOVamCLgbd1l6c

[@genelomas332]

fantastic info on how to make one, but what's the physics behind the phenomenon?

[@w13rdguy]

Best guess? The Coriolis effect.

[@erfinderwerkstatt]

Neat! Have done this with students a while ago... Not quite as pretty, but for 5 minute projects: Plastic spoon + paper clips or Plasticine will work as well. As always, thanks for posting these clips. They've inspired me as child, and deliver tons of ideas to try with students nowadays.

[@CuriosityShow]

Our pleasure. Please spread the word about the channel - we love getting visitors - Rob

[@JodyAlbright]

Me: I should go to bed. KZbin: Wanna see some weird rocks that spin backwards? Me: Obviously

[@StonyRC]

We had a programme in the UK in the 1960's and 1970's called "How". Very similar format and subject matter. Excellent TV.

[@JahRoo]

Not gonna lie, saw the sweater and heard something about magical stones and was thinking.."dear Lord I'm back on the wrong side of the internet again.."

[@lisalisa948]

Love watching these, learn something new every time! 👍

[@HiVizCamo]

I'm glad these exist in nature, who knows how many I've stepped over in the past.

[@YouFilthyAnimal]

Awesome show, great job!

[@CuriosityShow]

Many thanks - lots more at kzbin.info - please subscribe - Rob

[@colorado841]

Everyone asks what a Rattle-back is, but nobody asks how the rattle-back is.

[@mind7106]

Nice Thank you for making this video and sharing with us😍😍😍😍

[@procompsys]

" _Rob reveals why they behave as they do_ " No, he doesn't.☹️ Interesting anyway regarding what to look for when collecting pebbles.

[@lennytheleopard]

You guys were fantastic

[@arcynical8053]

The whole energy reminds me of Tim from Grand Illusions. Very nice!

[@bentrend]

The last time a stranger told me “to show you why I’ll need a flat surface. So you’ll have to come with me” it worked out VERY poorly for me

[@chrisvesy7245]

Very cool! I headed to the River to find one!

[@AdnanRiaz89]

The beautiful day of my life when I came on this channel...

[@CadmusCurtis]

It's too bad that show wasn't still going it'd be a great watch

[@ucanashtar3619]

Love this show. Reminds me of my old scout leader

[@rashidhaider9316]

Nice video and concept. I understood this reverse motion as the interplay of inertial forces (torque) and the equiliberium (center of gravity).

[@digitalninja85]

If you come across one of these be very careful because they are poisonous.

[@billvigus3719]

Only Eastern ones are poisonous. Western rattlebacks are harmless

[@ImpressionismFTW]

@@billvigus3719 I had a nasty encounter with a Western rattleback. Barely escaped with my life. Don't let a KZbin comment be the end of you.

[@alwayscoca-cola6487]

I wonder what I’ve done for the algorithm to welcome these videos into my life

[@glennllewellyn7369]

Best ATV ever!

[@SofaKingShit]

This segment was probably responsible for hundreds of dads spend thousands of hours looking for their punch.

[@rhysknight8681]

You guys are great. Keep at it and you'll make it in no time!

[@superformOG]

40 years later and im still being amazed

[@kevinogracia1615]

Highly amusing. Cool!

[@glennllewellyn7369]

Best TV ever!

[@hootybear]

Fascinating, thanks!

[@eecforeststewardship640]

OMG- this is wonderful- thank you for uploading these

[@RossMarsden]

I never knew these existed. I'm going to be obsessed in a river bed or the beach now.

[@Redbodhi]

The wardrobe is the true curiosity

[@dethvyper3136]

I used to love watching that show in my teenage years

[@maartenperdeck798]

The first stone you used, looks a hammerstone as used for flint knapping in prehistoric times. The ends of the stone show the typical signs of such a tool.

[@TheGodsrighthandman]

I'm reminded of the UK TV program from the late 70s "How!" with Fred Dinenage and Jack Hargreaves.

[@porkchop4401]

Saving this for when my little girl has a science project

[@TrapperAaron]

You can also tap repeatedly on the end to make it spin and make it spin faster. They used to sell plastic versions os a celt called space pets in Edmund scientific. I have a few around. This show has destroyed more spoons than heroin. Rip spoons.

[@barnabywilde374]

i'm gettin' this term RATTLEBACK confused with Diamond Backs which are rattle snakes. I hope i made that clear to my brother who's going out to find some today.

[@flowergrowersmith449]

But where does the energy come from to make it spin in reverse?? Is it the final rocking motion?

[@hgbugalou]

Kinetic energy via gravity.

[@christophersavignon4191]

Yep, it's the tilt combined with the angle of the contact points that reverses it.

[@colemanadamson5943]

Nice explanation except gravity exists only in pseudo-science. Never proven. A better explanation would be buoyancy w/ electro-magnetic actions. (Cavendish's experiment was a big nothing burger.)

[@kaikart123]

If you rock the stone back and forth, it will turn left/right. If you spin it in the opposite direction it turned when it rocks, when it finally wobble, it will surely goes to the opposite direction. It is that simple.

[@GeorgeRPope]

It spins back because it stops with the center of gravity on top and gravity pulls it back down.

[@BrendanTripp]

As I look at these, I have to wonder - at the point where the spinning item has stopped - how is the energy/force "stored" to then reverse the spin?

[@garygrinkevich6971]

Its like the rotation of the stone and the different axis produce a sine wave via "rocking" motion in the x and y axis that produce a waveform that rotates in the opposite direction. reminds me of the optical illusion one can observe when looking at a hub or fan rotating, at the right speed it almost looks like its not moving or moving in reverse.

[@garrettadams6165]

Off to the garden supply to rummage through their rocks now

[@seankkg]

"It's a rather clumsy affair," no kidding.

[@AngryHybridApe]

This still doesnt explain why Barney Rubble has no neck.

[@dddhhh2612]

like those totally honest fingertips at 4:15. No Hollywood there!

[@Igotknobblies]

Wife always looks for stones with holes through them. I know what she's going yo say to me now.... "Why are you taking all those wierd stones home"!🤣

[@andrewmize823]

For some reason, this made me think of Mr. Wizard.

[@ClickClack_Bam]

Made one of these when I was 9 & now the whole zip code calls me "Nail bomb Neil".

[@trublgrl]

@1:30: "I've emptied out the contents of an egg without cracking the shell". Points to whopping great hole cracked out of the shell.

[@CuriosityShow]

Thanks. Curiosity Show was a national science program for children featuring Dr Rob Morrison and Dr Deane Hutton. It was made in Adelaide, South Australia and screened nationally in Australia as well as in Europe, Asia and Australasia (14 countries) from 1972-1990. Deane and Rob intentionally used everyday items around the house (like old cans) so that children could repeat the demonstrations with materials they had to hand. In 1984 Curiosity Show won the Prix Jeunesse International, the world's top award for children's TV programs. Rob and Deane are steadily uploading segments at kzbin.info Why not subscribe?

[@spock7945]

wow! as someone from Bharat en.wikipedia.org/wiki/Bhārat_Gaṇarājya i didn't even realise they were Australian (i've actually never come across, till now, of someone from down under whose accent was not.. well theirs was easy o grasp. i did not think of them as Australians). i don't think this got telecast on our (till then) singular state broadcasting corp. and even if it did, we didn't really grow up (to be allowed TV) till the early 1990s

[@BodywiseMustard]

Lmao ^

[@Joostinonline]

@@CuriosityShow Go home, you're drunk

[@NathanStar-vw3dm]

@@Joostinonline no they responded to an initial comment that was later edited

[@AngryHybridApe]

What happens if you spin it opposite direction? Or if you glue that angled piece at a 90° turn from where its at now?

[@CuriosityShow]

Depends a bit on the specimen. Rocks may work, but angling the plastic straight on does not - Rob

[@AngryHybridApe]

@@CuriosityShow If it was at a 90° turn, it would still be at an angle. Suppose looking straight down at it with the egg (spoon or what have you)pointing directly vertical, north & south. The present angle of the plastic is n/e and s/w. What if it was n/w & s/e? Or vice versa?

[@AngryHybridApe]

@Kay Kay Ah ah ah ah

[@digitalninja85]

Halifax Gibbet its entirely possible that it could force a permanent defraculated feedback loop. Or it just might not work.

[@AngryHybridApe]

@@digitalninja85 Even with an anti-defraculated feedback looping device? ( just got mine back from the shop)

[@4dub802]

Idk y I like this series!

[@CuriosityShow]

Thanks. Curiosity Show was a national science program for children featuring Dr Rob Morrison and Dr Deane Hutton. It was made in Adelaide, South Australia and screened nationally in Australia as well as in Europe, Asia and Australasia (14 countries) from 1972-1990. Deane and Rob intentionally used everyday items around the house (like old cans) so that children could repeat the demonstrations with materials they had to hand. In 1984 Curiosity Show won the Prix Jeunesse International, the world's top award for children's TV programs. Rob and Deane are steadily uploading segments at kzbin.info Why not subscribe?

[@martinkasse1932]

From what I can tell the Rattlebacks have a preferred way of spinning. If you Spin it in the opposite way the Object tries to use the Energy to spin in the other way and they each cancel out in the horizontal direction, and gets instead transferred in the vertical direction. This process however seems to be irreversible so the Energy goes rather into rotation again and chooses the preferred direction this time.

[@COMB0RICO]

Thanks from Texas.

[@Actingskint]

Who knew it, Bob Ross wasn't just a painter

[@gregjones3660]

Wooooow!!!!! Neato gang!

[@cam-inf-4w5]

Its probably (my guess) because the spin is what makes it go one way but its the rocking that makes it come back? I remember spinning creek rocks on park tables as a kid but i didnt like these ugly stones. I didnt know i was playing with the laws of the universe. These are shaped really close to a muscle shell also.

[@uniseine]

I made one in 1981 with a chicken egg, a shish kabob stick, and no plaster.

[@valmarsiglia]

I'd like to hear about the mystery of that sweater.

[@DelTangBrav]

Is this why Australians also sandpaper cricket balls? ☺☺☺

[@CuriosityShow]

Now Now - but who can blame you - Rob

[@AngryHybridApe]

Doesnt that irritate the cricket? Lol

[@AngryHybridApe]

I used to use mothballs alot. But animal rights activists said it was cruel to cut their balls off. Kinda hard getting their legs apart too

[@spock7945]

*+Dagwood Dogwood* oh my $!^@!~ing god! i didn't even know crickets had balls (testicles).. now i'd look even more loony next time i hear one and eventually catch hold of one trying to investigate its underside!

[@kattyjeynna2015]

So goooood

[@cabletie69]

nicely done.

[@yarbles_]

That's a beautiful sweater.

[@rushiedits1333]

Great ❤️

[@tonys.4308]

You never explained why it changes direction.

[@The_Real_Indiana_Joe]

@2:13 Largest finish nail I've ever seen.

[@sparkyheberling6115]

What is the scientific reason for its reversal? And why does it matter what direction you spin it?

[@evolutiondailiam7733]

I'm way behind, need so much to lean, understand, discover n invent.

[@planktonfun1]

it converts horizontal spinning motion into vertical oscillation

[@urbanexplorer1754]

You are a genius Rob

[@CuriosityShow]

Many thanks - lots more at kzbin.info Please spread the word - Rob

[@TaxPayingContributor]

That's it in a nutshell. CGI wont do, however we have 3D printing that can fit the mould. Trigonometric Spirograph with exponentiating centers of gravity, viola.

[@allgames1920]

Why they don’t do such a show now days?

[@ToIsleOfView]

Great, but there is no explanation of why. I bought 6 plastic rattlebacks and it's obvious they are engineered to do this but they all must spin in the same direction to work so why can't we make them to spin in both directions or at least in the opposite direction? There is something about the angle of the weight that creates the backspin. can someone confirm this?

[@i7Hcrank]

Just found this show. Its 2022.

[@kevindunlap5525]

Shape and momentum, that's all. Still interesting.

[@thepixelatedpie]

They just happened to have a random metal punch on set? I don’t know why but I find that hilarious

[@nigel900]

Interesting.

[@dracobruhma]

I wanted to click to a new vid....but watched the whole thing

[@moistenvelopes]

I like his wall

[@johnridgeway6718]

The Russians did a simple spinning experiment in space, no gravity situation. An odd weighted object spun up and it wobbled a bit and then suddenly flipped and reversed it's spinning direction. It was a small hand held object. Very interesting demonstration.

[@cmoor8616]

Different principle, rattlebacks depend on friction and balance. The instability of L shapes in space is fascinating though.

[@drdca8263]

@@cmoor8616 thanks for letting me know that it is by a different principle