Another way of saying it that makes Toms argument quite a convincing one is that helium creates a force relative to the environment it is in. Helium by itself doesnt create lift, the difference in density between helium and its surroundings creates the lift. It may not even create lift, put a helium filled ballon in a vacuum and it will sink like a stone.
Monday, June 24, 2002, 1:35:38 PM, you wrote: TR> The point is that helium doesn't create lift. That's saying that helium TR> creates a force on itself - which makes no sense. >>right , if helium doesnt creat lift, then why when i put helium in a >>baloon it rises? if i dont put helium in a baloon it doesnt rise? so how TR> I don't think that a bike frame would hold much more helium than a TR> baloon, and even then it's only lifting a rubber baloon weighing a TR> couple of grams. The lift on a 10kg bike would be negligable. But then TR> again, so would the weight saving of a vacuum in the frame! TR> - Tom TR> PS Good thing we have these pointless debates to mill over or else I'd TR> probably get pretty bored :) TR> mark krawczuk wrote: >>dunno. i pesume that it would stay on the floor because there is helium >>every where. >>of course helium + helium = helium >> >> yes , but wwhat about a ballon full of helium, in earths normal >>atnmosphere? it floats!!! so helim floats. >> i think we where talking about helium filled tyres? who wants to drive with >>helium filled tyres in a helium filled enviroment? >> >> mark k >>----- Original Message ----- >>From: "Tom Richardson" <[EMAIL PROTECTED]> >>To: <[EMAIL PROTECTED]> >>Sent: Monday, June 24, 2002 11:39 AM >>Subject: Re: nitrogen filled tires >> >> >>>Mark, >>> >>>Imagine a room full of helium. Now place a baloon full of helium in it. >>> What happens? >>> >>>- Tom >>> >>>mark krawczuk wrote: >>> >>>>right , if helium doesnt creat lift, then why when i put helium in a >>>>baloon it rises? if i dont put helium in a baloon it doesnt rise? so how >>>> >>i >> >>>>figure it helium creats lift............ >>>> >>>> mark k >>>>----- Original Message ----- >>>>From: "Tom Richardson" <[EMAIL PROTECTED]> >>>>To: <[EMAIL PROTECTED]> >>>>Sent: Sunday, June 23, 2002 11:50 PM >>>>Subject: Re: nitrogen filled tires >>>> >>>> >>>>>Helium does not create lift. Rather, the force on the helium molecules >>>>>(due to gravity) is smaller because it has a lower mass than air. Think >>>>>of holding a ball underwater. >>>>> >>>>>Substitue the mass of a vacuum (zero) into this equation: force = mass * >>>>>acceleration and you'll see what I mean. >>>>> >>>>>- Tom >>>>> >>>>>James Cox wrote: >>>>> >>>>>>Hum.. I don't know about that, sure that may hold true with no >>>>>>athmosphere but helium being lighter than air, creates lift, and thus >>>>>>less weight, even though the mass would be larger. >>>>>> >>>>>>(I got no idea how we got into this discussion on a Datsun forum!) >>>>>> >>>>>>James Cox >>>>>> >>>>>> >>>>>>>Yes. A frame full of helium would have more mass than a frame under >>>>>>>complete vacuum, therefore gravity would exert a larger force on the >>>>>>>helium cos of one of Newton's laws, Force = mass * acceleration (ie >>>>>>> >>>>even >>>> >>>>>>>though helium is lighter than air, it's still heavier than nothing) >>>>>>> >>You >> >>>>>>>can't really use vacuum filled tyres though :) >>>>>>> >>>>>>>Aren't these digressions great? Who'd have thought there was a use for >>>>>>>high school physics >>>>>>> >>>>>>>- Tom >>>>>>> >>>>>>_________________________________________________________________ >>>>>>Join the world's largest e-mail service with MSN Hotmail. >>>>>>http://www.hotmail.com >>>>>> >>>>>>--membersozdat------------------------------------------------------- >>>>>>OZDAT Mailing List Please Note:- >>>>>>Send (un)subscribe requests to [EMAIL PROTECTED] >>>>>>Send submissions to [EMAIL PROTECTED] >>>>>>No unauthorised redistribution of this email >>>>>>http://www.ozdat.com/ozdatonline/index.htm >>>>>>http://www.ozdat.com/ozdatonline/listindex.html >>>>>>http://www.mail-archive.com/[email protected]/ >>>>>>--------------------------------------------------------------------- >>>>>> >>>>> >>>> >>> >>> >> >> -- Best regards, Bob mailto:[EMAIL PROTECTED] --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/[email protected]/ ---------------------------------------------------------------------
