A better weather balloon, safer for sea-snacking seaturtles?
May 4, 2015 10:13 AM   Subscribe

How would we release a weather balloon and get it back without its exploding?

Here in Key West, as a summer project for kids we are looking to release a Go-Pro attached to a balloon to record video of ascent and descent. However, the problem is that when weather balloons get high-enough they explode creating spaghetti-like pieces of latex rubber that sea turtles may eat because of the pieces resemblance to jellyfish. This is dangerous.

How would I release a weather balloon with the intent of recovering it with said explosion? Or can an alternative material be used that does not explode into pieces?
posted by Mike Mongo to Science & Nature (4 answers total) 2 users marked this as a favorite
I've seen it done with a giant mylar sack only slightly filled - as the gas expands the sack fills out. I don't know what would happen when it ruptured, if it did in fact rupture, but it wouldn't turn to mock jellyfish, I don't think.

I bet you could fashion one from emergency blankets.
posted by dirtdirt at 10:35 AM on May 4, 2015

You might see if some extra weight could be added to the balloon base (not your detaching payload), so that when it hit the water, it would sink more rapidly, instead of dwell near the surface where a turtle might mistake it for lunch.
posted by nickggully at 11:53 AM on May 4, 2015

An alternative would be NOT to release the balloon, but to use a lightweight fishing line and reel it in afterwards. My son did this as part of a Boy Scout project. The balloon did not go as high as a free-floating balloon, but it did have the double bonus of him getting the Go-Pro back (not a guarantee with other methods) and having the video right away.

You will NOT get the 15,000 foot video under this method, but it does have it's advantages.

My guess is it only went up about 1,000 feet.

Use helium if you can. Better lifting power.
posted by Colonel Sun at 12:10 PM on May 4, 2015 [1 favorite]

Force the balloon failure before it bursts, and then recover it with the gopro camera.

As the balloon rises, it will expand. It may be possible to contrive a non-stretching girdle, with a shielded point that will pierce the balloon after it fills the girdle.

Another method for destroying a latex balloon before its time is the use of oil or vaseline. A dab of calibrated vaseline or other petroleum distillate will eventually weaken latex. If the latex is under sufficient pressure, the weakened portion will prevent the balloon from bursting. It might be possible to contrive a method of keeping the vaseline off of the balloon until it had inflated to a particular diameter.

If that doesn't work, use a timer, and a small heating element fashioned from a 1.5 volt incandescent flashlight bulb. You can use the gopro battery, perhaps, to provide power to burn through the base of the balloon.

You might also be able to prematurely deflate the balloon with a high-voltage spark. If you use hydrogen as your lifting gas, Dog only knows what collateral damage might result from such a spark. You could use a high voltage capacitor as the energy source, and a simple pressure operated switch (a bladder and a flexible copper strip).

Naturally, there is a lot of engineering and testing that goes with reliable operation of any of these methods.

I live in an area where dead aluminized mylar balloons congregate, and I have never seen one with the strange fingery appearance that latex balloons often manifest when they burst. The mylar balloons retain some lifting gas when they make groundfall but never rise again.

The mylar balloons seem to overcome the adhesives in their filler neck below 2000 feet, but of course these were filled until they were bulging at sea level. Perhaps they would fail the same way if they were underfilled at sea-level so they didn't overpressure until they were very high.
posted by the Real Dan at 3:00 PM on May 4, 2015 [2 favorites]

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