> > I saw this: > > 10. "When shipping a package, add helium filled air pillows to reduce > its weight - thereby saving on postage, helping the plane fly and > reducing emissions." - Beekman, Chicago > > here: > http://www.labnol.org/home/best-money-saving-tips-from-google-tipjar/7978/ > > And it seems wrong. While helium might possibly be less dense and > lighter than what you're shipping, will it reduce the weight of the > package? <http://blog.prathambooks.org> >
This is a common misunderstanding, and to some extent the root of it lies in physical terms in english also have meanings in the common language. One of the most confused terms is "Work". In physical terms a porter who carries your luggage over a distance over his head (after lifting it onto his head and not including putting the luggage down from his head) does no "Work", but in terms of common language, there is work done. Its interesting that the Japanese use seperate terms for physics than common language and remember reading somewhere that this makes it easier for them to understand concepts in physics. On to the problem at hand. Weight should not be confused with "Mass". Mass is a property of all bodies and no packing of helium baloons is going to reduce it. "Mass" when acted on by gravity, is "Weight". And therefore, while the weight of the package may be reduced (if the package is suspended in air due to the helium baloons around it), its mass remains the same, and therefore energy is expended in transporting it from A to B. There are other concepts applicable here - I think that of physical systems. Even if the package is suspended in air, it is still moving at the same speed as the airplane and the load of this is on the the airplane engines. Hope this helps, this as good as my memory of 11th grade Physics serves me :) Kiran
