[wxgesr]

1000 gram weather balloon, took 3/4 bottle of helium to inflate properly IIRC for upper air soundings BITD underway, roughly 1000 ft per minute ascension rate with met package.

[Daffynition]

As a family activity, we've enjoyed those *solar balloons*...fun 'n cheap and they can really get *up* there...with the ideal conditions. :)