2006-12-22 01:39:33 · 3 answers · asked by sunny p 1 in Science & Mathematics ➔ Chemistry
Due to lighter weight of Helium.
Helium is the second lightest element.
Its molecular weight is 4 amu
Average molecular weight of air is 28.9 amu
Thus He is definitely lighter than air.
Thus Helium gas has a tendency to move upwards through the atmosphere.
Hence when you let go of helium-filled ballon,it rises.
Whereas an air filled balloon following the principle of buoyancy has the same weight as that of the outside medium and hence sinks.
2006-12-22 01:41:42 · answer #1 · answered by Som™ 6 · 1⤊ 0⤋
Buoyancy is caused by the following:
The weight of the balloon and the air inside is a certain amount.
The weight of the balloon and helium is much less. It is the weight difference between the two that gives it the upward buoyancy. In fact the measurement of the buoyancy is the difference in the two weights.
2006-12-22 01:45:24 · answer #2 · answered by eric l 6 · 0⤊ 0⤋
Because helium gas is lighter than air so it floats up, taking the balloon with it....The air filled balloon has air which is, of course, the same as the air on the outside of the balloon plus the weight of the balloon itself....so it sinks.
2006-12-22 01:46:50 · answer #3 · answered by Tallulah 4 · 0⤊ 0⤋