Centripetal swinging tray, improving an old demonstration

The centripetal swinging bucket ad tray demonstrations has been around for centuries and is a classic physics demonstration that can be done at students of all ages. Changing fro using a bucket of water to using a tray with cups of water was a good improvement in the demonstration and in this video I attempt to some additional upgrades to the demonstration to make it a bit more interesting.
this video is a reposting of a previous video that included copyrighted music. It has been removed from this version
Here is another KZbin video on the swinging tray that I posted previously • Swinging tray -centrip...

[@TheOMAha94]

Bruce, you should really put up a science-themed restaurant, where waiters bring drinks to people like this.

[@johnsch8634]

and then it bumps into a table... 🥲

[@melody3741]

In some fancy restaurants they used to use these specifically to prevent spills. Maybe still do idk

[@johnsch8634]

@@melody3741 I could actually see that, since a fancy restaraunt would be more sedate and less likely that you'd end up bumping the tray.

[@LiftPizzas]

And the straws are 33 feet long so you can't drink out of them. :)

[@TheOMAha94]

@@LiftPizzas unless the restaurant is located deep underground or in a submarine :)

[@1986BBG]

Love this teacher, keep up the good work Bruce. Cheers

[@EDMPeretti]

Hey Bruce! I'm just starting out my career as a science teacher and finding your channel has made me so happy. I've been watching every video! Thank you so much!

[@YeanyScience]

I'm happy to hear that, my original goal was to show other teachers ideas that I found useful

[@crazykittenvideos855]

Great video, I am relieved you didn’t fall off the stadium as you were swinging it round! You will need a hammer thrower with higher speed and strength to see what string length can be achieved😁

[@iHamadQ]

what a wonderful clip, keep going Mr. Bruce. I am from Saudi Arabia and I like to watching your videos.

[@PeetHobby]

This is perhaps the most popular experiment in the world.

[@manouchk38]

4:56 the free fall phase is amazing! What I love in free fall, is that raising object are also in free fall...

[@MusicByRyder]

Bruce, you are simply one of the best. Thanks for all the knowledge and laughs you've shared over the years. You are a true hero, good sir🤝

[@_casg]

Wow I always had a dream of trying this with lots of cups of water and bro made it happen.

[@BlindSpotLightBox]

Your videos are always very inspiring! Thank you!

[@markschippel7974]

I love the idea of having the students build their own apparatus to push find limits. I have been using a trick that I learned in junior high. Take a wire coat hanger and stretch it out into a long diamond shape. If necessary bend the hook so it points straight up when the coat hanger is hung from the top of the diamond. Now the fun part. find an older penny with the Lincoln Memorial of the back. Balance the penny on the hook and try to get it spinning around your index finger. Once it is spinning it is quite stable. Then the trick is to stop it without the penny falling. It takes some practice but it is quite impressive once you get the hang of it. Most coins should work (unless they have a hole in the center) as long as they have one face that is pretty flat. Also, some coat hangers have a bevel cut on the end that may have to be filed flat. Once I get the penny stopped I shake the hanger to prove the penny is not glued on.

[@Yezpahr]

This was an epic show of skill, you make it look easy. This is one of those experiments that can mess with people's minds, it can look fake or unreal even when you **know ** this is real. In fact, if you hadn't shown those two fails I would have been one of the first to jokingly mention "glue is still an option" in one way or another haha.

[@thedevilinthecircuit1414]

Fascinating stuff as always!

[@Vindictator1972]

I haven't watched you in a hot minute but you truly do make science fun.

[@palarious]

I think you'd love science and futurism with Isaac Arthur. He talks about space based applications of things like this

[@melody3741]

LOVE the more in depth videos please do more

[@bhopro]

When I taught this topic, I also made some circular saw blades out of paper and attached them to hand drills with magnets. They worked brilliantly for cutting pieces of foam. Just keep your finger clear because that would be a nasty paper cut.

[@tylerddh]

Crazy you can throw it, I'm gonna try juggling this at some time

[@MrWiseinheart]

8:17 thats a creative perspective.👍

[@Warrentheo]

I hadn't seen this one before this, it would be interesting to see the change from the concave of earth gravity to the convex of centripetal 'gravity'

[@Tann114]

Love it! Nice spinning skills, reminds me of poi or diabolo a bit.

[@hunterboat]

Thank you Bruce

[@AtaGunZ]

Turkish tea seller tray, they used to do this to get attention and sell more tea

[@michaelwinter742]

Make one with students on a swing set!

[@murfburffle]

Some kind of wizard!

[@FrankLassowski]

Hej Bruce, your students must love you 🙂 I definitely would have back in the days if I had you as my science teacher. But no, there were mostly boring folks… 😞

[@Sk8trgod420]

What a Badass

[@MarleneWalker-su8ku]

Bruce the kinda guy you bring a cup of tea , open the door , and wake up in hospital with a bandage on your head😂

[@KnowArt]

I'd love a good youtuber battle of this

[@ghostagent3552]

Like I know how this works but I can't help myself with feeling the fear of the water falling if one spins it wrongly

[@cbluebeard]

Very cool. As a kid, I would do this with a stretched out metal coat hangar and a penny

[@reyb925]

It would be good if you could measure the speed of rotation and capture several pictures of the horizontal angle at different speeds of rotation, and then draw conclusions on the horizontal angle of the liquid surface as a function of the speed and the length of string.

[@lightdark00]

I didn’t think you could improve the past video, but you moved it up to a circus level performance.

[@wolf7115]

It's like a miniature form of artificial gravity.

[@Atheistic007]

With an 18ft (~5.5m) string the tray is travelling ~8.2m/s. One revolution ~2.1 seconds.

[@PavelMostovoy]

Thanks , for yours vudeos. One simple question. When you release this construction for a "free" fly... seems the center of rotation is somewhere near to water. So, probably there is not enought centifugial acceleration to keep water in place. But it steel there. How it selfbalanced ... ?

[@ivekuukkeli2156]

This centrifugal force is clear to me, but why sand corns center in rotating water in a bucket?

[@vennic]

I do this trick with my kids in the hammock to give them a ride

[@bramfran4326]

You are now Certfied Centripetal force bender. 😅

[@icebluscorpion]

I would love to see the lager one again and the string progressively getting shorter and then eventually stopping it like the short one. 🤔 Edit :never mind I saw it

[@TaxPayingContributor]

Science!

[@ThePhlimphlam]

Bruce! Did you used ever take your demonstrations to elementary schools in Reno Nevada in the early 2000's? If I found your channel all these years later, wow.

[@YeanyScience]

I have been to Nevada a few times, Reno once but not for related activities. I've done demonstrations for various schools and science teacher conferences, mostly on the east coast.

[@Juttutin]

I'm intrigued about the physics of bringing it to a halt without spilling. Why is it easier with shortening the string? It's there a physical reason it's impossible to bring to a stable halt at 14 ft? Is the system stable as it 'coils in' around a cylindrical axis (it looked like it).

[@CraigOverend]

Probably because your arm can only move so far to dampen the oscillation.

[@artperson]

aaaaaaa... ok, now it’s clear why we didn’t fall from the Soviet swing during acceleration, when we made “sunwheel”

[@robotomhk3718]

I hear cups of water screaming

[@JeredDanielson]

Someone get this guy some glowing poi lol

[@lauxmyth]

Well, you are ready for a circus.

[@VACatholic]

If the centripetal force pushes the water towards your hand, why is the water as far away from your hand as it can get? Seems like you're missing at least one force.

[@zbyszekkopec908]

The Earth is flat with Firmament, and stationary.