Why does a helium weather balloon expands as it rises in the air.? Assume that temperature remains constant?

Question

Why does a helium weather balloon expands as it rises in the air.? Assume that temperature remains constant?

Answer 1

The Helium is added to the balloon at atmospheric pressure.

Helium is much less dense than air.

The balloon therefore rises. (Due to the lower density within it....like a lower density 'Thermal' in the atmosphere).

As the balloon rises, the outside pressure decreases due to the decreasing height of atmosphere acting upon it.

(The temperature can't remain constant but, the effect of the decreasing pressure outside is greater than the effect of the decreasing temperature of the Helium).

The internal pressure tries to get outside and, in so doing, the balloon expands to equalise the internal pressure with that of the outside atmosphere. Eventually, the expansion will cause the balloon to burst and fall back to Earth.

(Notice the balloon is not filled and is very slack when released. This is to allow the expansion to take place).

Answer 2

ITS BECAUSE ON INCREASE IN HEIGHT THE ATMOSPHERIC PRESSURE DEC THUS USING BOYLE'S LAW PV=NRT THUS VOLUME BEING INVERSELY PROPORTIONAL TENDS TO INCREASE WITH DEC IN PRESSURE.

Answer 3

refer boyle's law pressure is inversely proportional to volume

as height increases,  pressure decreases therefore volume of gas present in balloon increases hence balloon expands.

Answer 4

Helium expands in heat, and contracts in cold. Heat rises, so as the weather balloon rises in the air, the heat from the air is making the helium expand, thus making the balloon expand. :)