The students all received their ping pong satellites back and wrote their conclusions. You can check out all of the student experiments and their hypotheses and conclusions on our Balloon Experiment Tracker page. A lot of the conclusions were not returned because our launch was so close to the end of the year :-(
So what did we find in the data??
Well, here's the gist:
TEMPERATURE RANGE: 36 degrees C (after landing sitting in the hot sun) to -57.5 degrees C at about 50,000 ft.
PRESSURE RANGE: About 82,000 Pa on the ground before launch to 50 Pa at the highest height about 65,000 ft (there's a reason I don't know the exact altitude that I will discuss later).
ALTITUDE RANGE: 5260 ft on the ground up to what we estimate was a burst altitude of about 65,000 ft, maybe up to 70,000 ft.
So what happened??
We launched at 9:14 am MST (15:14 GMT) and from what we can tell from the data, the balloon was rising at about 6 m/s, which is DOUBLE what we wanted to rise. So we definitely put too much helium in the balloon. High Altitude Science, the manufacturer of the balloon and rig we purchased, had great directions on how to fill up the balloon, but the scale that came with the kit was a bit finicky and I couldn't tell if I was at the right positive lift. Based on my calculations, we needed a total lift of 2000g for the balloon, but once the scale hit about 1800g it didn't move easily to the 2000, so we put too much helium in the balloon (which also explains the premature burst).
We watched the balloon rise straight up for about 15 minutes (seriously, straight up), and then we came back into the school to setup at our Balloon Tracking Command Center where we logged into the site where we could track our SPOT Tracker. The students that were part of the recovery team were glued to the screen waiting for the GPS ping every 5 minutes. We were also frantically trying to update the school, the blog, and social media.
But why don't we know the exact altitude?
Unfortunately, when you check out the data, our flight computer stopped giving GPS and altitude data at about 46,000 ft (14,216 m). Therefore, we have had to piece together temperature and pressure data (because thankfully those were working!) to conclude where our max altitude was. We think that the max altitude was above 60,000 ft since we lost contact with the SPOT, but that it didn't go a lot higher in that time period, at most another 10,000 ft based on ascent rate before we lost track of the altitude on the computer. But here's an awesome shot of that altitude!
We sent up roughly 50 student experiments packed into ping pong balls to see what would happen to certain materials at high altitude. We packed the ping pong balls into a mesh sack and tied the sack to the bottom of the rig.
Six days after the launch, the students came back down to look through the data, videos and open their experiments. Overall, mostly nothing happened to the experiments. But a few students sent materials up that changed composition or color such as putty, seeds, etc. The most interesting was that silly putty turned hard and gray. Also some homemade slime became very sticky and loose. The students wrote conclusions based on the data and their observations and were awarded with a nifty certificate of completion.
The launch was a success even though we didn't get to the height that we had hoped for (100,000+ ft) and we learned a TON about what it takes to launch a balloon, recovering a balloon, proper balloon launch safety and regulations, the science of weather, the science of the atmosphere, and the importance of teamwork!
We will definitely do this next year too! Just with some adjustments this time! Can't wait!
And we got some awesome videos of launch and ascent! The GoPro turned upward a little on the bouncy launch, but it's still a cool angle. Go to 4:00 on the launch video to skip right to the take off. You can see just how fast it was going!