- #1
mcandrewsr
- 9
- 0
I had to do an experiment in which I built examples of hexagonal closest packing, face-centered closest packing and a body-centered space lattice. I had to find the volume of a box that would fit tightly around them, and then calculate the density in units/cm3 (assuming a mass of 1 unit per sphere).
I know the packing efficiencies are 74%, 74%, and 68% respectively (based on online research).
However, my results do not remotely reflect those numbers. There are 13 units for both hexagonal and face-centered, but the size of my "imaginary box" around them is different (and there is no possible way they can be the same). I assume I'm supposed to get the same density for those, but that is not possible when you have the same number of units but a different size of box. (Body-centered has 9 units...and according to my measurements has a greater density than hexagonal- and I measured REPEATEDLY to check).
I have spent 2 days trying to figure this out and it is getting frustrating. Any guidance would be greatly appreciated!
I know the packing efficiencies are 74%, 74%, and 68% respectively (based on online research).
However, my results do not remotely reflect those numbers. There are 13 units for both hexagonal and face-centered, but the size of my "imaginary box" around them is different (and there is no possible way they can be the same). I assume I'm supposed to get the same density for those, but that is not possible when you have the same number of units but a different size of box. (Body-centered has 9 units...and according to my measurements has a greater density than hexagonal- and I measured REPEATEDLY to check).
I have spent 2 days trying to figure this out and it is getting frustrating. Any guidance would be greatly appreciated!