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Surface volume-density
m2/m3
Scale of some things
 Area Volume
How much surface-area can you pack in a volume?
 Rough Draft
How much per .

m2/m3
grain size ...
... ...
104 m 10-3
103 m 10-2
102 m 10-1
101 m 100
1 m 101 1 m sphere, cube | ~ human (skin only)
10-1 m 102
10-2 m 103 ~ human
10-3 m 104 ~ lungssand
10-4 m 105 ~ capilariesfine sand
10-5 m 106 ~ mayonnaise (oil droplets)silt | suspension
10-6 m 107 colloid | suspension
10-7 m 108 colloid
10-8 m 109 ~ sorbent / molecular sievecolloid
10-9 m 1010 moleculessolution | colloid
10-10 m 1011 atomssolution
10-11 m 1012
...

## Landmarks

1 m3 cube's area - 6 m2 (101 × 0.6, exact (6 sides))

1 m3 sphere's area - 5 m2 (101 × 0.5, +3%, ±<1%)
 101 × 0.4836 ±<1% 4pir2 for r = 0.6204 m so that 4/3 pi r3 = 1 m3 101 × 0.5 +3%, ±<1% 101 +×2, ±2%

Surface-area volume-density (m2/m3) for grains is about 6 × grain width-1
 So 1 m grains give 6 m2/m3, 10-1 m grains give 101 × 6 m2/m3, and 10-2 m give 102 × 6. 6× assumes grains are smooth cubes. Its 5× for smooth spheres. And any roughness would increase this by introducing additional (smaller) "grain" sizes. The 6 (or 5 or whatever) is dimentionless (m3/m3).

 A View from the Back of the Envelope Comments encouraged. - Mitchell N Charity

```Doables:
lawn example, charcoal/sorbent filtering example
molecular slices.  oil on water.
charcoal
clay silt soil etc.  Films and wilting point.
clarify grains.  droplets etc.  simple closed volume of m^-1 10.
clean up landmarks
link to sphere when that gets cleaned up
I am unsure what to call this
area volume-density
surface-area volume-density
surface volume-density
```
```Notes:
sorbent 103 m2 / gram [SciAm 96oct p115]
lungs 10^2 m^2 over 10^-2 m^3 lung
skin  10^0 m^2 over 10^-1 m^3 human
capilaries 10^4 m^2 over 10^-1 m^3 human

"sorbent to sphere" (this concept bogus, left as a reminder)

Names&more names: <1 nm = solution; 1 nm to 1 um = colloid; >1 um = suspension
```History: