## burhan101 3 years ago Fermi Problem: How many paper clips in a jar with the following ? The Jar: 6.5 litre capacity Length and width of 1 paper clip: 2 x 0.5 inches

Since there is no dimension given for the paper clip thickness, there could be a whole lot, an infinite amount.

2. CliffSedge

^ has a point there.

convert the 6.5 liter to cubic centimeters. convert the dimensions of the paper clips (when you have all 3) length, width, and depth) to centimeters. Convert to cubic centimeters and divide into the cubic centimeters of the jar. That would be one method, but in this case, I would borrow a whole bunch of paper clips and fill the jar, then count them.

I don't know how to calculate the space used up by a paperclip. Maybe find its displacement in water...????

5. CliffSedge

I know the Fermi Problem method is to make an 'order of magnitude estimate.' 6500cc's by (I'd estimate 1.25cc's per paper clip) I'd get around 5000, but given the margins of error (which are large), I'd put the orders of magnitude between 1,000 and 10,000

6. CliffSedge

@radar, I don't think the exact volume of the paperclip would help since their negative space contributes as well (stacking problem). There is also the issue of unperfect (random) stacking from the assumed 'just-pour-a-bunch-of-paperclips-in-there' method of filling the container.

Oh, I was completely off base, as I wasn't even considering Fermi, is this the same Fermi that did work in quantum mechanics and in semiconductors?

8. CliffSedge

^ Yeah, Richard Feynman talked about him a lot and spoke of this method.

Yes I agree, the geography of a paper clip would preclude an orderly calculation.

10. CliffSedge

I think he used 'back-of-the-envelope estimate' as a descriptor as well.

Thanks, I learn a lot from this Open Study.

12. CliffSedge

Me too!

Nice chatting with you CliffSedge.

14. CliffSedge

Same, Mr. radar. What do you think, @burhan101 ?

15. burhan101

this is a really complex question, i have like a white board with stuff on it haha :\$ still in the process of finding a reasonable way to approach this

16. CliffSedge

The reasonable approach is to guess and not be too outlandish about it.