Ever wondered how far a party balloon can fly if you let it go, and how long it stays in the air? Turns out they can fly for over a hundred miles and for at least 8 hours or so. I discovered this when I released an aluminized party balloon from the UNC Chapel Hill Campus with my email address attached. This afternoon, I got an email from a resident of Pantego, North Carolina – a sleepy town of 200 people located right near the seashore, about 135 miles from Chapel Hill as the crow flies. She found it in her front yard at about 10 AM today.
I released it at about 8 AM yesterday morning, so it probably arrived sometime last night. I’m actually surprised it travelled such a short distance given that it was in the air all day – but it could be that it did not take a direct flight path, stayed low to the ground (where winds are milder) or landed yesterday and she just didn’t see it.
She said that there were no rips in the balloon, so it must have lost its helium in transit. This is rather surprising, since it sat in my lab for about 2 weeks and only lost about half its volume. I assume that the increase in internal pressure compared to external pressure as the balloon rises increases the rate of helium loss.
The reason I had this balloon is because I recently passed an exam, so my mom sent me a floral arrangement with a balloon that said “Congratulations! You did it!” Initially I was curious to see how long it would take to lose its buoyancy. Once it was clear that the end was near, I figured it was a pity to waste a perfectly good balloon, so I attached a message and let it go.
Launch: 8 AM, March 11th, at 35.908101 North, -79.052106 West
Landing: Sometime before 10 AM, March 12, at 35.589202 North, -76.662261 West