After hearing several hours of lecture from Dr. C.Y. Chien on “Order of Magnitude Estimation Problems,” we felt we owed him one. We invited Dr. Chien and the physics department at large to make their own estimate: how many balloons does it take to fill the foyer in the main office?
(Team First-Year: I put everyone’s pictures and movie clips together in this zip file.)
- Numbers:
- Total balloons inflated, filling foyer & mailroom: 2500
- Balloons filling foyer only: 1670 +/- 20 (some popped)
- Our initial estimate for foyer only: 1400 (based filling a 3-meter cube with 30-cm balloons at 72% packing efficiency)
- Time to fill foyer: 3 1/2 hours with 6-8 people working at any given time
9 responses so far ↓
1 whitbeck // Apr 3, 2009 at 2:40 pm
Nice. This looks awesome. I have one question though, how is your homework going : )
2 KT Foster // Apr 3, 2009 at 4:37 pm
AWESOME!!!!!
I am impressed
3 Miles // Apr 4, 2009 at 11:08 am
It sure beats stuffing human bodies into phone booths. But why assume such a low packing fraction, considering the deformability of ballons?
4 Ivan Kirov // Apr 4, 2009 at 1:41 pm
Greetings from a fellow graduate student in New York.
You guys did an awesome job!! From what I read it seems that the real number of baloons was exactly halfway from yours and your professor’s estimate. The moral? You should’ve inflated them some more:)
5 Dan Allan // Apr 4, 2009 at 1:47 pm
We happened to know that best possible sphere packing is about 0.74, and we didn’t think that a fully inflated balloon would compress very much under the weight of other balloons. It seems, unsurprisingly, that the oblong balloon shape packs more efficiently than spheres. This and some deformation are probably the most important sources of error. (Also, we did not account for the exact dimensions of the room or the furniture in it; that wouldn’t be in the spirit of a “Fermi estimate.”)
6 Caylynn // Apr 4, 2009 at 6:13 pm
Wow.
7 Theresa // Apr 4, 2009 at 8:19 pm
Excellent work. Speaking from my own personal experience of filling a Phase dorm room with balloons, I hope everyone enjoyed this educational endeavor :)
8 David // Apr 6, 2009 at 8:47 am
If you’re not quite as ambitious as the physics students at JHU, then you might try this technique, which gives the *appearance* of a completely filled office:
http://www.instructables.com/id/How-to-Fill-an-Office-with-Packing-Peanuts/
(I have no estimate of how many packing peanuts it takes to fill an office.)
9 Sveta Z. // Apr 6, 2009 at 9:44 am
Do I assume that order of magnitude guesstimates do not work? Neither you guys not the professor got the number close enough…I guess you would NOT be getting that Chrysler on the “Price is Right”:-) Love the idea…
Leave a Comment