# Helium filled school bag .. **URL:** \ **Category:** Factual Questions\ **Created:** [April 10, 2008, 11:58am UTC](https://boards.straightdope.com/t/helium-filled-school-bag/444751 "2008-04-10T11:58:07Z")\ **Posts on this page:** 10\ **Page:** 2
**Author:** ![bannerrefugee](https://avatars.discourse-cdn.com/v4/letter/b/c68b51/32.png) [@bannerrefugee](https://boards.straightdope.com/u/bannerrefugee)\ **Post date:** [April 10, 2008, 4:14pm UTC](https://boards.straightdope.com/t/helium-filled-school-bag/444751/21 "2008-04-10T16:14:17Z")
Doesn’t hydrogen produce more lift? What could go wrong? ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [April 10, 2008, 4:19pm UTC](https://boards.straightdope.com/t/helium-filled-school-bag/444751/22 "2008-04-10T16:19:47Z")
[QUOTE=bannerrefugee] Doesn’t hydrogen produce more lift? What could go wrong? [/QUOTE] Oh, the humanity! ---
**Author:** ![Declan](https://avatars.discourse-cdn.com/v4/letter/d/ecae2f/32.png) [@Declan](https://boards.straightdope.com/u/Declan)\ **Post date:** [April 10, 2008, 4:23pm UTC](https://boards.straightdope.com/t/helium-filled-school-bag/444751/23 "2008-04-10T16:23:47Z")
[QUOTE=indian] Anyone got any practical suggestions to reduce the weight of the bag ??( apart from carrying lesser books 😃 ) [/QUOTE] Keep the weight the same and hire a sherpa for the haulage. Declan ---
**Author:** ![mwbrooks](https://avatars.discourse-cdn.com/v4/letter/m/ba9def/32.png) [@mwbrooks](https://boards.straightdope.com/u/mwbrooks)\ **Post date:** [April 11, 2008, 9:51pm UTC](https://boards.straightdope.com/t/helium-filled-school-bag/444751/24 "2008-04-11T21:51:24Z")
Get the kid interested in weightlifting. Then the bag will _seem_ lighter. Your post reminded me of a kid’s book I read once in which someone invented a sort of negative-weight metal, with all sorts of interesting consequences. The book was _Peter Graves_, by [William Pène du Bois](http://en.wikipedia.org/wiki/William_P%C3%A8ne_du_Bois), and you can bet it’s hard to look up on the web! ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [April 11, 2008, 9:55pm UTC](https://boards.straightdope.com/t/helium-filled-school-bag/444751/25 "2008-04-11T21:55:08Z")
[QUOTE=Qadgop the Mercotan] Wait! I know! Let’s compress the helium, so we can get more into the bag! That’s sure to work. Compress it enough, and we’ll get liquid helium, which is known to flow uphill! It’ll be great! [sub]yeah, that’s the ticket![/sub] [/QUOTE] The discussion is helium; not hot air. Although in sufficient quantities, both should work. 😃 ---
**Author:** ![Can\_Handle\_the\_Truth](https://avatars.discourse-cdn.com/v4/letter/c/6a8cbe/32.png) [@Can\_Handle\_the\_Truth](https://boards.straightdope.com/u/Can_Handle_the_Truth)\ **Post date:** [April 11, 2008, 11:52pm UTC](https://boards.straightdope.com/t/helium-filled-school-bag/444751/26 "2008-04-11T23:52:28Z")
[QUOTE=indian] Anyone got any practical suggestions to reduce the weight of the bag ??( apart from carrying lesser books 😃 ) [/QUOTE] Photocopy the chapters that the kid is working in currently and have him carry only those. Keep the actual books in his locker so he can get to them in the event of any surprises. ---
**Author:** ![mwbrooks](https://avatars.discourse-cdn.com/v4/letter/m/ba9def/32.png) [@mwbrooks](https://boards.straightdope.com/u/mwbrooks)\ **Post date:** [April 12, 2008, 12:20am UTC](https://boards.straightdope.com/t/helium-filled-school-bag/444751/27 "2008-04-12T00:20:19Z")
[QUOTE=Can Handle the Truth] Photocopy the chapters that the kid is working in currently and have him carry only those. Keep the actual books in his locker so he can get to them in the event of any surprises. [/QUOTE] Hey, that’s a good one! Here’s another idea: see if any of the books he has to carry are available as E-books. If he carries a laptop, he can keep them in there. Otherwise you might consider getting him something like an old Palm or a Kindle (although Kindles are really expensive for a kid to carry around). Of course, E-books won’t help much if he’s expected to have a particular edition, with page numbers that match everyone else’s. ---
**Author:** ![DSYoungEsq](https://avatars.discourse-cdn.com/v4/letter/d/c6cbf5/32.png) [@DSYoungEsq](https://boards.straightdope.com/u/DSYoungEsq)\ **Post date:** [April 12, 2008, 12:25am UTC](https://boards.straightdope.com/t/helium-filled-school-bag/444751/28 "2008-04-12T00:25:31Z")
[QUOTE=Rhythmdvl] Put the kid on a treadmill? It _will_ “reduce the net weight the child has to carry.” 😃 ETA: I hope this wasn’t taken with offence… I wasn’t calling your kid roly-poly, I was referring to a long-standing (treading?) reference. [/QUOTE] Nah, he’ll never get there because the treadmill or his shoes will fall apart from the stress of the acceleration… :eek: ---
**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\ **Post date:** [April 12, 2008, 9:36am UTC](https://boards.straightdope.com/t/helium-filled-school-bag/444751/29 "2008-04-12T09:36:36Z")
OK, now what if the OP fills the child with helium… 😃 ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [April 12, 2008, 5:07pm UTC](https://boards.straightdope.com/t/helium-filled-school-bag/444751/30 "2008-04-12T17:07:11Z")
On a railroad-oriented board there was an argument over whether a helium tank car was lighter full or empty. I pointed out that there’s nothing magical about helium, helium balloons float because the helium in the balloon is less dense than the air it displaces. If you compress the helium, as you undoubtedly would do in loading a tank car, at some point the helium will be denser than air, and the car would weigh more. My quick calculations put that point at about three atmospheres, a mere 45 psi. Then I pointed out that an ‘empty’ helium tank almost certainly was not flushed out with the helium replaced by air, but rather just trundling around with one atmosphere’s worth if helium still in it. The lightest car of all would be one that was emptied by sucking out the helium and corked shut with a good, hard vacuum inside. [Previous page](https://boards.straightdope.com/t/helium-filled-school-bag/444751.md?page=1)