Rubber Band Heat Engine

[xijnnijx]

so if you had something to cool it on the other side, would it be able to spin faster?

[st1cklebr1ck]

@xijnnijx Exactly correct. Cooling the bands would allow them to lengthen on the opposite side to it would help shift the centre of mass even further from the axis creating a larger moment around the axis.

[Measonz]

Rubber Band Heat Engine is very good video

[osbiath]

This is awesome! I work at a fast food restaurant (Paying my way through college to become an engineer =) ) and a friend and I were thinking about all of the heat that was being lost from the grill and said "There has got to be a way we could use that wasted energy"... I wonder... Anyways thanks for the video.

[st1cklebr1ck]

@osbiath Although heat is (energy) is always conserved, when ever you make it do work there is an increase in the total entropy of the system. The entropy is a measure of how much useful work the heat can perform. The only closed system is the universe as a whole and eventually all of the energy will no longer be able to do work because the system has reached it's maximum amount of entropy. This is known as a heat death and it is thought that this will be the ultimate fate of the universe.

[komaki119]

Mate....

a lump is something you hope not to find, I think you mean to say LAMP.

[neverquit250]

very cool :)

[kaulas123456789]

how it works with light?



[TuringMech]

@kaulas123456789 Well it works with heat. Since the lamp heats the rubber bands and they thereby expands and therefore carrying less weight than the other upper sit side. The fan side therefore falls down.

[st1cklebr1ck]

@kaulas123456789 The majority of the radiation coming from a filament lamp is in the infra red part of the spectrum. It is these wavelengths that will be doing the majority of the heating.

[coldarc]

what about replaceing the rubberands with springs, and use magnets to contract them on one side instead of the light? since the light only act as a force, and not as energy source, the wheel turns because of a weight differential and not a temperature differential. of course the temperature differenial is what causes the weight to differentiate in momentum between sides. there is no heat exhange in it other than a transfer of energy. motion is not directy caused by the heat.

[saf768]

u could have used black rubber bands because they absorb more heat and it should been fast

[mjinen]

will this work outside in te sun?

[st1cklebr1ck]

@mjinen as long as you stop the sun radiating on half of the wheel, yes it will work.

[Philip614]

Whats the title of the book he mentioned it in?

[checkmatedeepblue]

The Feynman Lectures on Physics

[scientificpages]

@checkmatedeepblue when i saw this I instantly think abouth Feyneman idea about rubber engine :) thanks for making it!

[PattyMMelt]

just for future reference, thats a LAMP, not a LUMP... i see you've misspelled it in several of your comments as well as your description

[checkmatedeepblue]

Thank you for your kind attention

[PattyMMelt]

@checkmatedeepblue

Hah, no problems. I was being a Grammar Nazi, but still glad that I could help. :3

[weblips]

Very interesting!

[superfunnyman123]

interesting concept? :D

[thetrolone]

that rubber should banned!

[schumispecial]

Great idea, but: using maybe 500 W lamp to get maybe 0,5 W from the axle...besides, the heat from the lamp could as well rotate a propeller assembly of some kind above the lamp better. To get the best results, this rubber should have maximum thermal expansion on the other side, and maximum contracting on the other. This, added with the necessary heat, makes huge stress to the rubber, and it is prone to age the rubber quite rapidly, I think.

[kdober6]

Joule Effect: If a freely suspended rubber strip is loaded/stretched and subsequently heated, the strip will contract and lift the load. Conversely, an unloaded strip when heated expands to the coefficient of expansion for that rubber.

This phenomenon of contraction is termed the Joule effect and occurs only when heating a stretched rubber object.

[nobiscuits4u]

Just as an fyi, if you used all darker rubber bands, you'll have a much smoother rotation. That could be the reason for the delay after the initial rotation.... when it's all yellow rubber bands in the light, having started with mostly darker bands in the light. And yes, rubber bands *contract* with energy due to the polymer bonding within. Nice work!

[heloizyjhenifer]

The least energy efficient engine ever, but smart ;)

[aragon89]

the problem is that the next rubber is too cold so it takes time to heat it up.

anyway, it s cool!!

[JonnyRawket]

That's not the problem, it's the reason it works. If the rubber bands were pre-heated, the temperature differential would be less, leading to poorer performance. The best solution would be to intentionally cool the bands 180° away from the heat source.

[NoiseyEagle2]

there's a fan in the back

[HOPPERFZR]

thats not a fan its a stirling engine

[NoiseyEagle2]

oh cool how does it work

[HOPPERFZR]

when you heat the rubber bands they expand letting  the rubberband on the otherside pull the ring off center ,which happens to become the heavy side ,gravity turns the wheel

[tuffpee]

Almost, but backwards! When you heat a rubber band it actually contracts! You can test this by hanging a weight from a rubber band and bringing a flame close to it.

So what's happening here is the bands under the lamp are contracting. Assuming that the axis of the wheel is fixed, then the parts of the tire connected to the contracting bands get pulled closer to the center. This moves the center of gravity of the wheel to the (screen) right of the axis, and so the wheel rotates!

[humperfier]

@tuffpee im pretty sure cold makes things contract, that is why when its cold you have to stretch your muscles more

[theledkid2]

when it's cold you get increased electrical stimulation sent to your muscles to flex them to warm you up. its not contracting its twitching. sheesh

[st1cklebr1ck]

@humperfier Indeed, making things cold does indeed make the majority of objects contract; but not rubber. Due to its polymeric structure, when you lengthen an elastic band you align the polymer fibres so they lay in the same direction. This corresponds to a lower state of entropy because it is more ordered. By removing heat from a material you lower its entropy. In the case of a rubber band, the lower entropy state is a longer, more aligned configuration.

[sleptlateistheworse]

Nice dude, 5/5. It looks the most simple heat engine in the world. :) (Its not that I dislike, its so amazing.)

[ollieoniel]

maybe if you put a fan on the other side to cool the bands it would work faster.

[navegente]

How about sun light and lens?

[deaftodd]

Interesting, but it's the most inefficient motor EVER seen.

[princesskyuh]

nice.. i appreciate the effort and the idea and facts you imparted.. thanks.. because of this, i already have an idea on how to make my own improvised heat engine and will have something to submit for my physics project.. lotsathanks...

[klcflyer]

How many joules of heat energy were expended in getting the wheel to rotate exactly 1 turn? I think I would have rather had the heat.

[roxasnriku1]

Are you english?

[pfc3]

If the rubberbands had a significant melting point then this thing could have done a lot of work.

well my question is what would happen if we're using a material that expands when heated?

[pfc3]

I guess then it would fall off the wheel. What I'm confused about is when rubberbands contract, they pull, causing the force being pulled towards the center of the wheel, how does that make the wheel spin? is it centripecal force or whatever its called?

[Nasty0suicide]

When the rubber bands contract and pull the center harder, the center of gravity is not anymore where the axis is. The right side of the wheel is heavier and gravity pulls it down

[Wcoltd]

I was wondering how it worked, that's interesting.

[Nasty0suicide]

if it would expand instead of shrinking, the wheel would spin to the other direction

[cardcutter]

what law does this demonstrate and how cant find too much on it

[ballsniff13]

thats cool hows it work

[ballsniff13]

holy fuck you dick lick you can at least be nice

[gonitronow]

higher heat will help...not too high as to melt the rubber bands

[Pudersepp]

Hm... stuff does not contract that well when heated. I rather think that the opposite side of the wheel, opposite to the side being heated, is allowed to pull the center of mass towards it. The rubber bands coming from the light source contract after chilling out in air.

Regards

[osterianio]

rubber is one of several materials that contracts whens heated

[SmiertSpionem]

That is bonkers! Talk about inefficient.

inspiring nonetheless :)

[nxc42]

haha genius!

[smartstuff2buy]

need supplies for your experiments?

contact me

[GAMBITBZ]

If you put independent axis for the whell and the rubber and diferent position this may work faster.

And the rubbers paint in black.

[smartstuff2buy]

you will be arrested for hacking the free energy out of the earth, i'm petitioning you now to the game managers

[Bonznumber1]

your an idiot

[NerdPuppet]

I think you mean "you're"

[Bonznumber1]

OMG nitpick much?

[NerdPuppet]

There's a kind of irony in what you did, too bad you can't see that.

[Bonznumber1]

you see the irony comment is a comment that has been posted on many free energy vids i called him an idiot cause this is nothing like that and you point about something cause i wasn't paying attention i doubt that was typed by mistake

[NerdPuppet]

yoo, caynt .. spyll ; and yur gramur and and and pungchew aye) shun suks(.,/';

[Bukuzoid]

Enormous effeciency :-)))

[lollnessxD]

ISNT IT L A M P NOT L U M P???? O_0

[rguerzo]

I'm sure it will work outdoors too. On sunny days, cover half of it with a cut-out box to shade the other half.

[1crazyfocker]

that realy cool well need to try to make one of those my self

[frezzy11]

Are the rubberbands regular ones??

and where do you aim with the lamp

[checkmatedeepblue]

The rubber bands are quite regular ones in my country.

The aim of the lump is to heat rubber bands to contract them.

[hoser4]

Careful; frezzy11 asked _where to_ aim the lamp, not _what is_ the aim. I've already provided the correct answer for the question. Hope this clears up any confusion.

[elie5252]

lol im guessing in ur country lamps r called lumps?

[fishkeeping123]

@checkmatedeepblue y u say lump? its lamp

[hoser4]

You aim the lamp so that only 1/2 of the exposed rubber bands are lit, so that only 1/2 of the bands are heated. The other 1/2 are allowed to cool, thus completing the cycle.

[westcaos]

What do you use to keep the rubberband in balance?

And how many Watt is the lamp?

[checkmatedeepblue]

I put some small metal wire on the side of the wheel to keep it in balance. The lamp is about 20 Watt.

[rocketcane]

cool, you had a stirling engine, i love those

[idontlikeyousomuch]

wouldn't the rubber bands be expanding? it would have the same effect obviously...

[pacogoatboy]

rubber is one of those strange materials that contracts when it is heated, at least near room temperature.

[jakegreenjake]

I'm also trying to make one using a bike wheel, but it was unbalanced. I'm going to try the video's method of Polystyrene. Any more tips would help! I'm trying to get this to spin a tad faster. Also, what type of rubberbands did you use and what is the wheel thickness?

[checkmatedeepblue]

I'm glad to hear that you are also trying to make the engine. I used several rubber loops which have 45mm diameter. You do not need to use pants rubber bands, its too thick and too strong in this case. Thickness of the wheel is 5mm.

[checkmatedeepblue]

Hi everyone, I'll show you how to make the engine as follows.

The outside and inside diameters of the wheel are 16 and 12 centimeters, respectively. Note that 1 inch is equivalent to 2.54 centimeters (cm).

[checkmatedeepblue]

In order to make the wheel you must write two circles on a polystiren board and put 16 marks dividing equally the circles. This is a geometrical problem. You may find how to divide a circle into 16 arcs by using a compass in your mathmatics or geometry books. If you can't find it, you can also use a protractor.

[checkmatedeepblue]

You need 8 rubber band loops and their diameter is apploximately 4 cm. You should hook the rubber bands carefully otherwise the wheel will be broken because of a weakness of the polystiren board. You must put all of the rubber bands symmetrically.

[checkmatedeepblue]

After you put the wheel on the pedestal, try to rotate it using your finger. If the wheel cannot rotate smoothly, it seems that weight balance of the wheel is bad. You can fix it using tiny metal wires for weight balance putting them on outside of the wheel.

[melissaxlove]

what do you use for an axle?

[checkmatedeepblue]

I used a piano wire which has 1mm in diameter for the axle. :-D

[checkmatedeepblue]

You can also change the weight balance by shifting the rubber bands a little by hand.

If the wheel become to rotate smoothly, the engine will also works well.

[checkmatedeepblue]

Remember that a sorce of power of the engine is the moving of the center of mass away from the center of rotation. I hope you can understand my poor English but if you have more questions, ask me anything again! Good Luck!

[melissaxlove]

My brother is doing this science fair project.

what type of light is best for this to work and what wattage does this have to be?

[checkmatedeepblue]

Hi, i used a normal 40W lump.

[melissaxlove]

Thank you, however, my brothers wheel is not moving. He came up with the idea from a book and used different materials than you. He used a wooden hoop that is only 9 inches in diameter and it does not appear to be able to move smoothly around a wooden dowel. Your comment on making sure that the wheel is balanced may be our problem. Could there be something else we are doing wrong?

[checkmatedeepblue]

The point is that weight deviations of the wheel must be eliminated. If you can see pendulum swung of the wheel, you may put counter balance (small metal films or something) on a top of the wheel to offset mass deviation at the bottom of the wheel.

[esserspace]

This is cool. Why does it work?

[challenger159]

Paint it black, it will pick up the heat much more effectively.

[stopglobalswarming]

Interesting. Have you tried large 0 rings, such as would be used in large-scale plumbing?

[checkmatedeepblue]

No i have not tried yet. i like to use a polystyrene sheet to make the engine. its quite easy to cut them.

[melissaxlove]

where do I get a polystyrene sheet?

[checkmatedeepblue]

You might buy it from a online shop on the web.

[tonyhursh]

It looks like the material he's using is what's commonly called "FoamCore" in the United States. You can get it at an art supply store.

[simi112]

pants rubber is thin and round . Its material is

much better. It responds more forceful.

[checkmatedeepblue]

Thank you for your comment. I need much more harder materials for the wheel in order to use a pants rubber bands.

[melissaxlove]

where do I get pants rubber bands

[simi112]

Good job!

I think a pants rubber is much better. Try it!

[mutwa]

I wonder if you could isolate two different sections 180 degrees on the wheel. Line it with two different materials which have a high difference in specific heat temperature, creating 1 area of cool, and one of warm, like copper and wool, just a thought. We know that most materials settle at different temperatures in a room temperature environment.

[checkmatedeepblue]

Thank you for your comment :D

Now I think that your comment is very understandable but the wbeaty's idea is more realistic solution to enhance the weel rotation. I will be very happy if the engine works effectively in spite of a small temperature difference.

[checkmatedeepblue]

Maybe i can use some metal material for the wheel , which have high heat conductivity like copper or alminium. The point is to enhance the heat transfer more effectively from the lump to enviroment through the rubber bands.

[wbeaty]

Or make a heat pump! Turn it with a gearmotor, pump air across it, and rotate an air-valve-hole which routes the air only across the cold bands (or across only the hot bands.)

[wbeaty]

I just discovered something while using a thermal camera to observe rubber bands. When stretching/contracting a rubber band, all the big thermal change occurs very near maximum stretch.

So, motor torque should greatly increase if bands and motor diameter are chosen so bands are nearly at maximum length. Pull HARD and they get hot, let them cool at maximum stretch, then relax a little and the get very cold.

[checkmatedeepblue]

Wow you are quite right. I hope I will make my engine better some day using your nice theoretical advice.

[Kevl3lade]

Hey do you mind telling me how to do this

[checkmatedeepblue]

i used a polystyrene sheet with 5mm in thickness for my heat engine because it is very light and easy to be cut. First a hoop was quarried out from the sheet. A piano wire was used for the shaft. i glued four plastic small beads on the wire using a quick-drying glue. Then i hooked rubber bands between the hoop and the shaft. you must hook them to keep force balance otherwise the hoop will be broken by the strong tension of the rubber bands!

[EinsteinVonRembrandt]

Nice job. To optimize, maybe use sunlight (slightly concentrated if needed) to heat the engine? Black rubber bands. Shield the rest of the rubber bands from light.

[checkmatedeepblue]

Thank you for your comment. That's nice idea. I also think that it is very important to make temperature difference between left-side and right-side of the engine.

[hamsterpoop]

awesome ;)