2006-11-17 12:08:06 · 5 answers · asked by kainia1 1 in Science & Mathematics ➔ Engineering
An balloon has positive buoyancy (floats) if the volume of air it displaces weighs more than the balloon. This is the same as saying the balloon is less dense than the air it is in.
In air, which is mostly nitrogen and only about twenty percent oxygen, a balloon will not float if its overall density is greater than air. That is, if the balloon and the gas it contains weighs more than the volume of air that it occupies the balloon will sink. So you can't fill the ball on with air and expect it to float because the balloon fabric is denser than air.
However, there are three (and only three) gases whose densities are less than air: hydrogen, helium, and hot air. If the volume of the balloon is large enough, the weight of the hydrogen or helium or hot air when added to the weight of the fabric will be less than the weight of the air the balloon displaces. The balloon rises.
All of this is commonly referred to as manifestations of Archimedes' Principle.
2006-11-17 12:42:44 · answer #1 · answered by hevans1944 5 · 0⤊ 0⤋
What type of balloon?
The general principle is buoyancy. When something is less dense than the air around it, it will float upwards. Really it is pushed or forced upwards by the air. The same principle holds true in water.
Hot air ballons that people can ride in work because hot air is less dense than cold air. Hot air ballons have a sort of stove that burns a fuel and heats the air inside the balloon. Once the air gets hot enough the balloon will float!
The other sort of balloon that you see at a birthday party is filled with helium. Helium is much less dense than the air we breath so a balloon filled with helium floats very well.
2006-11-17 20:12:24 · answer #2 · answered by Louis G 6 · 0⤊ 0⤋
using PV=nRT the air inside the balloon has the same pressure and volume so what changes when u rise T is n which goes smaller with smaller number of moles u get less mass so u have something less dense than the air at regular temperature, sum the forces m*g*h down way and Volume*air density*g upper direction which is greater than m*g*h.
2006-11-19 19:11:52 · answer #3 · answered by sergioqcostas 1 · 0⤊ 0⤋
well, what kind of balloon do you mean? Helium filled or air filled?
Helium balloons float because helium is actually lighter than oxygen.
2006-11-17 20:10:16 · answer #4 · answered by Denise 2 · 0⤊ 0⤋
Relative densities
2006-11-17 20:09:40 · answer #5 · answered by Up your Maslow 4 · 0⤊ 0⤋