Breaking Board Paradox--air pressure // Homemade Science with Bruce Yeany

The first time I saw the “Breaking board paradox” demonstration was on a short film clip on air pressure starring Julius Sumner Miller way back in the late 1960’s. It has never been a very popular demonstration but I’ve always found it amazing. The few people I’ve seen try to perform usually manage to break the board, but it and the paper go flying off showing a lot of motion which defeats the whole point of the demonstration. On closer inspection, I’ve noticed that narrow boards were usually used and I think that has been part of the problem. Through trial and error I’ve found that these don’t work nearly as well as wider boards.
All boards used are pine wood
3/16 inches thick , this thickness is not too hard to break and thinner boards are too flimsy
suggested width: minimum of 2.5 inches up to about 4 inches
board length 18 to 24 inches

[@hawkeyestiguy]

I bet no one disrupts your class. If they do, just break out this experiment. Haha. Love your videos! It great to see a teacher who is truly passionate about what he teaches! 👍🏻👍🏻

[@pianoman173]

Honestly this is the coolest and most informative channel I've ever come across. You deserve way more views/subscriptions than you have, it's a shame, I wish more people were interested in physics and the way our world works. Either way, please keep doing what you do. Always looking forward to the next installment!

[@YeanyScience]

Thanks Brandt, there are so many videos on youtube it's hard to compete. I still have several videos planned so I will keep going

[@andrechiapas5029]

Brant Holt

[@andrechiapas5029]

Bruce Yeany

[@blargkliggle1121]

I remember my 9th grade teacher showing us this, of course I also remember helping him call for medical assistance after he missed the board and hit the table, your version was much better.

[@chopmega]

It's a very impressive demonstration. I remember my teacher doing the same demonstration in about 1967 when I was 10 years old. He also told us it was a demonstration about air pressure. I now have a very strong suspicion it is much more about inertia of the air rather than air pressure, per se.

[@RoscoeKane]

The paper just helps form a seal to prevent air from getting under the board. Broader board harder to get air under. Try water to seal the board down.

[@unclesnail5063]

Roscoe Kane I was going to post this until I saw your comment. The vacuum created by the board is immediately filled with air if there is no paper, but the paper stops the air from getting in.

[@LimeyLassen]

4:24 It's so interesting how the board flew straight sideways. Like it was fired from a tube. 👀

[@xnortheaglex]

This is a really cool demonstration of how air pressure can affect simple things around us.

[@andrechiapas5029]

Lukenblaz

[@AaronzDad]

I think the previous poster nailed it already - it's the vacuum created rather than the air pressure pushing down that's holding the board on the table. When you have a wider board it's creating more volume of vacuum compared to a narrow board. When you smack the hanging end you're creating an instant vacuum underneath the other end which pulls the paper around it down to the table top. This is also why smoothing out the paper seemed to make a difference. The idea of using a mesh screen as a working surface is an excellent one, or even using a piece of pegboard or plywood with holes drilled in it to allow air to pass through. There would be no vacuum formed so the board would just go flying again. I bet ya a dollar!

[@lordiwa]

great work with videos, keep playing, keep having fun.

[@dractor3k]

Mark my words, you will be known. Great video!

[@YeanyScience]

thanks, I had hoped people would like these.

[@flopthis]

If there is any vacuum exits in our universe then, that means Its temporary thing like a newspaper because after you brake a board that is not necessary to hold a board a newspaper will be terminated. Holding an opposite and much more then an equal force of an air pressure will not hurt your paws but definitely hold distanced area of an object and short part will be easily break into a part. Very good. Nice education for students.

[@carmelpule6954]

Brilliant demonstration. I would suggest to put the wooden sheet in between two parallel high walls separated by the width of the wooden sheet, which will stop the air from getting underneath the wooden sheet. I like the paper demonstration, but it adds many other complications as the distribution of air pressure becomes complex . Sir, my congratulations, you certainly deserve great respect for bringing science to the school in this manner. Good luck and I do wish that there are many teachers in all schools doing what you are doing. These may be simple demonstrations but if one had to include the mathematics on them, learning Maxwell's equations and Navier Stokes equations will see this experiment to Ph.D levels. Well done Mr Bruce Yeany.

[@YeanyScience]

thank you Carmel, I am going to make a 2nd video on this piece and try some variations,

[@bishankagrawal2948]

thumbs up to the experiment and observation.

[@demitracondiles3428]

Best teacher I ever had! Thanks for showing me the coolest parts of science! -Demitra condiles- AC alumni. class of 2014

[@YeanyScience]

Thanks Demitra, that was really nice to hear.

[@luisj.serrano5821]

these videos are great, the only thing I miss is that being a science channel it should be metric so the rest of the world understand better

[@1252PFC]

Bruce, love your videos and energy about the subject. You and I are of similar ages and many times I tell or show my kids this method of learning (hands on vs virtual). Just one suggestion, please use safety glasses. For your safety and demo the importance of it in each of your future videos. thanks

[@siuhu91]

Amazing demonstration! I definately will use this with my students!

[@TheRebelmanone]

I've always pictured that as more of a vacuum that holds it down, but it all boils down to the same thing, pressure. In this case i pictured it being more negative pressure adhering the board to the table, than only positive pressure from above. But obviously it is both negative pressure when the wood tries to lift from the smooth surface, and positive pressure pushing on that small vacuum that sticks the board to the table, helping it stick a little bit more.

[@presistancelydeccer7338]

Ah. Learn a lot than I do at school. Nice experimentation stuff.

[@emielvanelzakker2137]

You make science very interesting! Keep on the good work!!

[@YeanyScience]

thank you

[@EmersonPeters]

The wider board forces a larger space under it that air needs to fill, and the paper is blocking this area. With the smaller board, it doesn't take much volume to fill under it at all, and the paper can just slide up at a 90 degree with it.

[@Htiler]

the board moves up, the paper seals between the board and the table stopping air rushing under the board. held down by a vacuum, the wider the wood the greater the vacuum caused by lifting. I like that one. you can stick a wall tile to a ceiling with adhesive and the vacuum holds it up there.

[@mrityunjay5400]

you are a Superhuman teacher....👍

[@GeneralSzadek]

very nice conclusion

[@traxxasking6235]

Nice best teacher he is my teacher

[@gamingscientist7445]

I hadn't seen that before. That's impressive!

[@onlyeyeno]

Astute observation, I was taught the "pressure against the paper" explanation, and accepted it without much further thought. But by Your "quick investigation" it's quite clear that it at least is not the entire truth. And I personally subscribe fully to Your explanation that the paper rather prevents air from rushing in under the stick, and this allows the board to "create suction" against the table surface. And it's this "suction between the board and the table" that is the actual "counteracting force", not the air pressure against the paper, "holding it down". One way to further establish if this the "suction of the stick" or the "pressure of the paper" is to, by some means, lessen the "direct contact" between the board and the table, thus lowering the "strength of the suction" but not changing the "pressure of the paper".Possibly this could be done by placing the board slightly elevated of the table surface, perhaps on a couple of toothpicks... All in all an enjoyable and educational video. Best regards.

[@YeanyScience]

thank you, I want to revisit this experiment and try some other variations, I will give what you suggest a try

[@Panj0]

Congrats on 10k subs! You deserve more; I'm sure you'll get them soon. :)

[@YeanyScience]

Thanks kcufO

[@Dummythiccdakota]

60k subs later

[@FearStricken]

Well, I learned something today. Thanks for the video!

[@bruderscience3274]

You remind me of my favorite science teacher Mr. Mylott!!

[@glenngriffon8032]

damn Mr. Yeany you a ninja.

[@davidcollins465]

awesome video!

[@andrewjenery1783]

You could make money with this, amazing.

[@Turnip0739]

You monster, kids in Africa could have eaten those boards.

[@Turnip0739]

Exactly. Now those kids will have smaller portions of baords. Less fiber. U=Monster (just in case i wasn't being ridiculous enough to make this obvious, I'm joking)

[@YeanyScience]

LOL, it was obvious the first time

[@thetheflyinghawaiian]

All of the sudden your demonstration turns into an example of conservation of mass.

[@carultch]

@@Turnip0739 I don't think kids in Africa can digest cellulose.

[@ronfowler6873]

I think it might have something to do with the ratio between the thickness and width of the board as well. I've seen this same experiment done before usually with just a wooden ruler that is maybe only an 1/8" or 1/16" thick by about 1" wide and it breaks every time without moving the paper. Also it may have to do with the type of wood used, the cut of the wood, and the size of the paper.

[@grzegorzkapica7930]

I think the paper just prevents air to be sucked below the board. you could maybe try with a peace of cloth, that lets some air throught.

[@kekistanprimeminister6876]

Grzegorz Kapica that's what he's saying

[@kimngantranthi3099]

your video is usefull for me, thank you very much

[@NixonMediTa]

Excelente, la cara de sorpresa en el experimento con la tabla delgada. Me pude reir. Buen canal profesor, Felicidades.

[@YeanyScience]

Gracias Nixon Medina

[@jth_printed_designs]

I think it's due to the vacuum created under the sheet, not the pressure on top.

[@MrJacobst]

Jordan Hillard I would argue that rather than a true vacuum the paper creates a large pressure differential and in that case the air pressure would be holding it down

[@Scientist_Albert_Einstein]

When you hit the board, it lifts the paper a little bit and creates a temporary vacuum. The bigger boards create bigger vacuums.

[@rio2ug]

you rock man. love your work😄

[@aerobyrdable]

Bruce Yeany is a down-on-his-luck physics teacher who has just learned he has stage III lung cancer. Determined to ensure that his family will have a secure future, he embarks on a career of drugs and crime. Recruiting a former student as a partner, he churns out hundreds of pounds of the purest methamphetamine ever produced. But has Mr. Yeany found the formula for success, or just a recipe for disaster? Vince Gilligan presents: *Breaking Board*. (rated TV-MA)

[@angrydragonslayer]

no

[@rio2ug]

Ryan Cook knows how to cook meth

[@golfercab7323]

lolz breaking bad reference, good one

[@likeyou3317]

That's what I thought when I saw the title. :D

[@Samrajel]

You maniac, i literally almost cried when i read "has stage III lung cancer", thank god i read the rest of the thing -.-"

[@HamIAm]

Thank you for your videos :)

[@ktimo100]

I think it might be because there is a larger vacuum under the larger board. And with the same mass of air in larger vacuum the pressure difference with the outside will be greater.

[@akhilbarackal8427]

I think narrower wood piece makes the paper more aerodynamic while in motion, hence lesser resistance on the paper.

[@weedium]

Good stuff, thanks!

[@j-swizzle1922]

This is sweet!

[@ionceateapinecone]

transference of energy, a similar experiment can be performed by breaking a bottle over your head; the energy is transferred into the bottle so fast that you don't feel the shockwave through your head

[@PeterMilanovski]

The air isn't pushing down on the plunger, it's the plunger pushing up against the air creating a vacuum. That's the difference. Same thing is happening with the piece of wood. The slower that air can get underneath it, the more vacuum is created.

[@dominictarrsailing]

you are hitting the board with the same force, but on the wide board there is more area, so the force per area is less. the paper is the same. the paper slows the air rushing in under the board, so you get a vacume. The paper can stop enough air to hold the large board, but not the small one. Perhaps a larger sheet of paper would be able to break the small board? surely if you reduce the size of the paper you'll get the big board moving the paper like the small one did

[@YeanyScience]

yes, it has been incorrectly explained that it is the total amount of air pressure on the paper that is holding the board down. The function of the paper is to keep air from getting under the board and the vacuum formed under the board is enough to break it. I show this better in the updated version of this demonstration. kzbin.info/www/bejne/b4nQgZiPe9Sngq8

[@laurensabbi4015]

Huge Fan

[@MrSsogeer2005]

good idea

[@dbeanmail]

Would this be a result of vacuum and the resistance of air rather than the force of air on it? Of course air pressure would also include vacuum but just represented by a negative #. My thought is that the newspaper may also help restrict the air from getting underneath the board by giving it a longer path to travel and create a "friction". What if you were to try the same thing using a piece of netting the same weight/size as the paper?

[@YeanyScience]

Hi Dustin, as you are suggesting, it is an imbalance in pressure. under the board would be a vacuum, on top, air pressure, with the paper restricting the air from getting underneath. netting would not work, several holes in the board and not covered by paper doesn't work either

[@gabejurich2245]

BOARD BREAKING CHAMPION!!!

[@janicupcake9080]

love ur Videos *-*

[@YeanyScience]

thanks

[@roguesciencesguy7256]

The surface area of the wider board allows more of the paper to come into contact thereby increasing the air pressure downwards.. Isint it ? It's all in the cross section.

[@nidhinandagopal4761]

Mr Yeany, I have a doubt. Can you please explain when you close a bottle , why doesn't it collapse on itself ? shouldn't it since the pressure outside the bottle is greater than the pressure inside .Thank you

[@diggoran]

The air you seal inside the bottle is already pressurized by the atmosphere from when the bottle was open. It will continue to press against the inner walls with that same pressure even once it’s separated from the outside air. If you sealed the bottle while it was in a vacuum, and then exposed it to the atmosphere, you would see it crumple like you expected (unless the bottle walls alone are stronger than the atmospheric pressure, like a thick glass bottle).

[@microdesigns2000]

It seems to me that the amount of air on either side of the board but under the paper is proportionally much higher in the narrow board. When you strike it, that air can fill the underside of the narrow board allowing it to move up before a vacuum is drawn in the area. With the wide board, the same air pockets to the side of the board is not enough to allow the wide board to travel very far before a vacuum maintains the position of the board. That idea could be tested on the smaller board by folding the paper to fill in the gaps on the sides of the board. I also wonder if the higher inertia of the board without a proportionally higher breaking force appreciably contributes to the results. Meaning, does the breaking force double but the inertia quadruples?

[@YeanyScience]

HI Dennis, I just had an impassioned disagreement on this piece with an old friend. We are both going to do some variations to try and convince the other of our points. It should be interesting to see the results. Should be out in January

[@microdesigns2000]

Hi Bruce, I hope you will post the results here. Rather than breaking more boards you might make an easier test with a fish scale and notice the peak force before the board is displaced from the table. If I get around to it, I might try this test myself. As for a hypothesis, maybe it was the words on your newspaper that were so heavy.

[@mdderrek9280]

You are amazing

[@holdenmontgomery2273]

Dude is a ninja no joke

[@ifluro]

Its the surface area of the board. A smaller board has to lift less surface area of the paper than a wider board.

[@EmceeIntricacy]

that was fucking awesome man!

[@SteveD826]

Hi Bruce, what do you suppose would happen if you did the same experiment, but on a porous table instead of the one you're using here?

[@YeanyScience]

HI Steven, good question, I am making a 2nd video on this and will try some other variations

[@garysooter2471]

I wish he had said what kind of wood was used. I'm an eighth grade science teacher and we're working on a physics unit right now. I want to do this demo for the kids but I bought basswood (tilia or limewood depending on where you are) from a craft store. Turns out basswood is very springy. The board didn't move but it also didn't break. I did scuff up my pinky trying to chop it though. Balsa seems to weak for this and I can't find pine in these dimension near me.

[@YeanyScience]

HI Gary, it is pine, I had to use a table saw to cut it thinner.

[@garysooter2471]

I thought about doing that but all I have is a handheld circular. I managed to get it to work with a 12"x3"x3/16" piece of bolsa wood. Not nearly as impressive but it still gets the point across.

[@luismaaaa]

Why is it a paradox??

[@BoxxerCore]

I know I would have enjoyed having an interesting science teacher like you when I was at school. My teacher's idea of a break from the textbooks was usually Electrical Bread board, battery, 2 wires and a bulb or coloured pens to draw atomic chemical bonds. I believe science can be the most interesting subject a child will learn in school, but an apathetic or lazy teacher can be off-putting for some.

[@gandluriabhilash6337]

Hi bruce, is this really because of air resistance against the board or because of small vacuum cavities created beneath the board??? I mean the wider the board the bigger vacuum cavities and hence more pressure is required to create and maintain one??? Isn't it??? ( assuming the air pressure trying to push through non porous paper and creating a glue like friction between the bench and paper)

[@YeanyScience]

I will be trying it again to get more answers for this

[@andregoncalves7856]

Doesn't the thickness of the board affect the result? I mean, couldn't you have the same result with thinner pieces that were also thiner in height? I am not sure if I am expressing myself correctly

[@YeanyScience]

Hello Andre, the thinner it is the easier it is to break, I will be making another video on this and that is a point that will be taking a look at. I will also try it with thicker pieces and see what happens

[@andregoncalves7856]

Bruce Yeany that makes sense. What I was trying to say is that small pieces all around maybe only need the piece of paper despite being easier to move. But I don't know as I study economics and not ciences

[@michaelehlers8299]

Awesome! Are you left handed?

[@YeanyScience]

thanks again, yes, I'm a lefty

[@bg6b7bft]

Do you think it might still work if you used cellophane? You _should_ be able to get a tighter seal with less material and it wouldn't hide the physics like paper does.

[@YeanyScience]

good idea, I am making a second video to try it

[@caitsith2]

Maybe, to add to the experiment, try smaller and smaller pieces of news paper, to find out how much the paper actually has to extend over the board. That is the one variable that didn't change in the experiment.

[@YeanyScience]

that is a good idea, I'm going to try that

[@paulholzherr2993]

Yeah, and you could try with no paper as well.

[@RoelNicky]

You should calculate the airpressure on each type of board

[@wayneswan3092]

Could it be vacuum from the paper against the table around the board? You're obviously a smart man and can figure out where I'm going with that, so I'm sure I don't have to explain.

[@YeanyScience]

Hi Matt, I'm finding that I can do with just a small amount of paper around the board if I wet it. My thoughts are the job of the paper is keeping the air from getting under the board itself. I am planning another video on this to show it

[@wayneswan3092]

Bruce Yeany yeah that's what I meant by the vacuum.

[@doublebassballz]

Bruce, if it is a vacuum you would probably get the experiment to fail if the board protrudes on both sides of the paper. I would like to see you try that.

[@YeanyScience]

I am planning a new video on this, thanks

[@sunnyshaw983]

Great..

[@etrou4]

How about using the same board but less newspaper? One variable at a time.

[@YeanyScience]

Hello Etienne, I'm planning to try another video with variations and see what happens

[@Astrelixia]

I think that this is just cool

[@Indigoway]

is it air pressure or vacuum? if the paper had a mesh below it that would let the air pass through would its holding power be the same? I just had a brainwave: if you used a suction cup in the vacuum of SPACE would it still work? I think it would - any thoughts on this 3-second old idea?

[@YeanyScience]

air pressure pushes down against the top of the board, as the board lifts very quickly, it is a partial vacuum underneath it. Good idea about the mesh, it wouldn't work on the mesh screen. I have been trying a few new ideas with this, and found it still works if I greatly reduce the amount of paper sitting on top of the wood. A suction cup would not work in space, it needs to an imbalance of pressure, no air on one side air pressure on the other

[@Indigoway]

Hey Bruce thanks for the answer. I do have a keen curiosity on this ever since my teacher did the holding water in an upside down glass with a sheet of paper. 1 - I have a sense that vacuum pressure or power may be stronger than air pressure. E.g. if it the pressure is 15 lb per square inch and a heavy duty plunger was used and had all the air sucked out i suspect that it would hold more than the 15 lb per square inch 2 - A plunger could be used to cause a vacuum and then put into a vacuum chamber to see what happens when all the air it taken out of the chamber. i suspect that the plunger will remain stuck as it is prevented from expanding not by the air pressure any longer as that has been removed but the seal preventing it from being able to pull in content to regain its full shape. If you do an experiment on this do let me know as that day in the classroom was 47 years ago ;)

[@helpmegetup]

ha ha 4:23 "bye bye"

[@vantatilfly]

let's try 10 inch boards

[@guitarslim56]

Why no goggles? You've got flying splinters!

[@letspartie]

would you try that over a cooling rack to let the air in?

[@YeanyScience]

yes, in the next video

[@onyxtay7246]

That's not a paradox. Its just unexpected.

[@YeanyScience]

true, but I didn't name it

[@onyxtay7246]

Bruce Yeany Fair enough.

[@chocobanh]

Avarickan paradoxes defy sound logic, even if that logic is wrongly founded; most people would not hypothesize that a thin piece of paper on a stick is enough to resist the board's tendency to go flying off after a hit

[@YeanyScience]

thanks Em

[@thatoneguy2254]

so size does matter

[@PBTophie]

1:52 & 5:37 This is a guy who loves what he does. ...or has dreams of being a kung fu hero.

[@alienhuntersd6879]

I think the teacher learn to much martial art from Bruce ( Lee / Wayne )

[@boooters]

^pretty shittty comment right here folks

[@alienhuntersd6879]

im sorry cause my grammar looks very bad...

[@boooters]

i love you buddy

[@alienhuntersd6879]

+boooters , why...

[@Resonanttheme]

It might be interesting to tape small flaps of newspaper to each side of the board without any above the board.

[@YeanyScience]

thanks, I'm working on that now.

[@Resonanttheme]

Another thing maybe would be to tape an equivalent area of newspaper as the original experiment to the edges of the board, none on top, but so that the paper is perfectly flat on the table. After that test perhaps a few dowels under the paper to keep it from resting on the table just to see what happens. As an aside I wonder how much weight an open sheet of newspaper could lift if taped to a long ruler so as to lift along the entire edge?

[@tylerpauli680]

I work for the newspaper. Now I need to bring in some wood and try this

[@wilber504]

did that as science experiment in the 5th grade(1960).

[@YeanyScience]

it's been around forever and the explanation for it has been wrong for just as long. I have a future video planned to show a few variations and verify my thoughts.

[@pikudopikao8425]

Bruce Lee? Fkng no! My master is Bruce Yeany. He's second to none!

[@alex_lomov]

i know... there is a hand under that paper... holding that board...

[@degenasis]

nice karate skills

[@rohitvaishya874]

A karate master

[@peteshea155]

you know we live on a flat and stationary earth surface bruce?

[@Braindizruptor]

if my physics lessons back in my teenage years would been like that i would not have sleeped in every hour.....(sry for bad eng)

[@donovanwisdom310]

Who is he counting off for?!? 1...2...3...Comment

[@YeanyScience]

LOL, I wondered that too after watching it

[@graymanmedia]

Aquaman did this same trick in Season 2 of the Superfriends.

[@mr.nobody...]

what an evil laugh =))

[@kanyegrande4312]

o dang im early. nice vid doe

[@YeanyScience]

Wow you're quick, I just posted this 3 minutes ago

[@kanyegrande4312]

I stalk your channel for science fair ideas :)

[@DasEtwas]

Decent Gaming haha nice

[@jpmyob]

SAFETY GLASSES!

[@shantv9446]

i read breaking bad on the title and clicked on it ....shit ..i thought he was going to be real life walter white