weather balloons are only partially inflated before they're released into the atmosphere. Whyis that?

Answer 1

in higher altitudes the pressure is lower, thus they leave room for expansion

Answer 2

The atmospheric pressure decreases with height.So, when a gas-filled balloon ascends,it is going on expanding till it finally bursts.Usually data is collected upto a considerable height(20 Kms atleast) with the help of the balloon.The balloon would have expanded many times before it bursts at that much height.
So,room is given for further expansion when it is filled so that we get enough data.
Further,the rate of ascent of a balloon also plays an important part in getting a correct data.The instrument that is attached with the balloon carries sensors for measuring temperature, humidity etc., and these sensors require some few seconds to record the data .If the balloon is ascending very fast,the level at which the data was recorded and the position of the balloon shown by the tracking radar may not coincide.Because,by the time the sensors record the data and pass it on to ground, the balloon would have ascended a cosiderable height and the data may not repesent the true height.To ensure the availability of correct data,an ideal rate of ascent shoud be calculated.
So, taking the above two factors into consideration,the size of the balloon,the amount of gas to be given are determined and accordingly,it is partially inflated and sent up.
In India, 20 Kms per hour is taken as the ideal rate of ascent and accordingly they are inflated.
When there is heavy rain, the balloon will start floating when it reaches the freezing level(the height at which the temperature becomes zero).This is due to the icing precipitation which presses the balloon downwards against bouyancy.So, when there is heavy rain,the balloon is inflated slightly more with additional gas to overcome the above problem.In such case , the balloon will burst a few minutes earlier which is not avoidable.

Answer 3

To allow for expansion. Since they lift the instrument package (called a radiosonde) to great heights (the average height of the balloon when it does burst is above 90,000 feet) they have to expand considerably. In fact, when released at the surface, most of the balloon average less than 8 feet in diameter. At bursting height, which can be as much as 115,000 feet, they are larger than house and nearly 100 feet in diameter.
If there was no allowance for expansion, the balloon would surely burst within a few hundred feet off of the surface which would limit the data. Minimum data from the balloon for a flight to be called successful is nearly 20,000 feet. The data is used for the mathematical models that run on the computers that are used by meteorologists to forecast the weather.

And most weather balloons use hydrogen rather than helium. (It costs less.) Helium is used when there is high risk of fire or with the portable systems.

Answer 4

PV=nRT
When the balloon rises, the atmospheric pressure and temperature would be reduced. As the pressure changes more than the temperature, the volume would be increased. If the balloon were too inflated, it could burst. The higher has to go the balloon, the less inflated has to be at the beginning

Answer 5

At higher altitudes, the atmospheric pressure declines, and the balloon expands. Room must be left for the helium or other gas in the balloon to expand without bursting the balloon.

At a higher altitude, the balloon will be full and spherical.

Answer 6

As they rise the density of the atmosphere is less. Then they will expand because the density inside will be greater in relation to the atmosphere. I hope I used the correct terms.

Answer 7

because of the fact the air larger interior the air is thinner and the air interior the balloon would have much less stress on it so it might stretch out extra. Its so while it stretches out extra it has room to and not pop.

Answer 8

Because as they rise the air expands, if they filled them too much they would burst.