Atomic densities and Packing Factors {Texas A&M: Intro to Materials}

Tutorial illustrating how to calculate linear densities, planar densities & atomic packing factors in an example (FCC) lattice.
Video lecture for Introduction to Materials Science & Engineering (MSEN 201/MEEN 222), Texas A&M University, College Station, TX.
engineering.tamu.edu/materials

[@benjamintan90s]

Sir are you creating more material science video?Your videos make material science accessible to the masses! Thank you and you are awesome!

[@Edward-gb8dx]

Thank you Dr Shamberger!!!

[@erickrobles6365]

How do you know the (111) plane cuts the atoms at 1/6? Is that something you must remember?

[@Evancade]

at 5:59 wouldnt that be 1/8 of each atom? or are we acounting for the sliced off area of the atoms on the side facing us?

[@amorfati9861]

6:30 is nt does 1/8 atomes and a half atome ?

[@parkerflop]

The equation at the top is just a bit confusing. There should be a V(cell) underneath V(atom)x(# of atoms) as well.

[@alexminich]

@5:07 pretty sure this isn't right. Need an integral number of lengths of a cell to calculate LD. Otherwise, to calculate LD in can take length = r and #atoms = 1/2 leading to LD = 1/2r which is incorrect.

[@pjshamberger]

As long as the segment of line you select can be repeated (linearly) to make up the pattern on the line of interest, then you are ok. Thus, the shorter segment I point at 5:07 (which consists of a single atom) is also acceptable, but that is the SHORTEST possible line segment one could envision using. In the example you describe, the minimal repeating length is 'a' (which you should be able to convert to an expression in terms of 'r' after watching this video!), and a line segment of 'a' units length contains a single atom (regardless of the starting position of that line segment).

[@alexminich]

Thank you for your response. I see every method as one that must apply universally to every case, so, I would say that to calculate LD one must always take an integral multiple of unit cell lengths (regardless of where you choose to define as the start of one cell length) and count the number of atoms in that interval. If you take a non-integer multiple of cell lengths (say 0.5 or 0.75 or 1.5) then the placement of the interval will affect the calculated LD.

[@KHMakerD]

The audio is not in sync with the video.