For particular personal reasons (not terribly unfathomable), I am particularly grateful to coffee this week. Not for coffee, but to coffee (and yes, to my coffee supplier, who has spoiled me such that I dread coffee shops, and can’t wait for my own home brew). I’ve written a few coffee verses over the years, and have long wanted an excuse to re-post the following verse, on the physics of the coffee ring. The full explanation is at the original posting.
In science labs and coffee shops
It can’t be helped; some liquid drops
On floor or table.
And as these spills evaporate
On table, napkin, floor or plate
The stuff’s unstable
When coffee dries, it forms a ring
Around its edge—but here’s the thing
We didn’t know—
See, other liquids just dry flat,
Without a ring. But why is that?
And off we go.
The scientists at U. of Penn
Perhaps were drinking coffee, when
They first surmised,
A detail that, before, escaped—
It’s how the particles were shaped
As well as sized.
And coffee’s little, tiny spheres
Flow edge-ward, while a rod adheres
And keeps to center
The little rods deform the drop
And should they try to move, it’s “stop!”
And “do not enter!”
So, anyway, it’s cool. They think
It might be used in paint or ink
For better printing.
With smoother drying, now each letter
Holds its shape and color better—
No more squinting!
The other thing is, through these studies
The particles are seen as buddies,
Fun little critters
We play each morning, our little game
I drink them down; they get the blame
For morning jitters.
Oooh, forgot about this one–still more coffee verse.