Can one person really do it?

In an introductory engineering class I took several years ago, a lecturer made the assertion that no single person could make something as simple as a pencil, any more. All of the specialized steps - from logging to processing graphite to finishing, etc. - are far too complex to be mastered by a single person. He was making a point about the interdependence of everyone in our current industrial world, and the important of stakeholders at each step of the way.

For some inane reason I recalled this assertion a few days ago, and realized that the lecturer had overlooked (or omitted) the hardest part of a pencil to make by oneself: the eraser.

Now, I know you are all thinking, "What on earth is he talking about? Erasers are incredibly simple! Is this going to be another annoying and trite post?" Have no fear, my intrepid readers! I actually have a small point.

Think about it: what goes into the design of a good pencil eraser? Well, erasers seem to work on two principles: smudging and graphite removal. The action of the eraser smudges the pencil marks (much like you could do with a finger, albeit much more efficiently), but also the little bits of eraser that come off 'pick up' the pieces of graphite and can be blown off (note how they turn black with graphite).

This makes extremely demanding requirements for a good pencil eraser. First, it has to attach well to itself and graphite. Second, the mechanical properties (particularly, but not exclusively, the Young's modulus) need to be optimized to allow the flexibility and "give" so that the eraser doesn't rip the paper - yet the eraser also must hold together strongly enough to not develop defects from erasing. Next, pieces of the eraser material need to be able to flake off as they are rubbed on paper. Add on requirements of being nontoxic, easily disposed of, inexpensive, reliable over a range of pencil and paper types, longevity concerns, etc... it becomes a very sticky problem relating to materials science, mechanical engineering, industrial and manufacturing engineering, and more.

Theoretically, one could just fool around and find something that works (which is how I suspect erasers were first developed), but to truly optimize the design, this requires extremely careful thought and a team of specialists.

So, to sum up, erasers are quite impressive and cool. Next time you need to fix a math problem (or a crossword puzzle, for those of you poor souls no longer taking math), appreciate the sheer genius of the simple things around you.

Obscure joke of the week

Courtesy of HaRav HaGaon HaNichbad Dune Shlita, I bring you a joke that half of you won't get and the other half will think is hilarious:

What do you get when you cross a Yekka and a Lubavitcher?





Someone who is always exactly twenty minutes late.

(Now's your cue to laugh.)

That's replaced my old favorite, the muffin joke. (Two muffins are sitting in an oven. One muffin says, "Boy, it's hot in here!" The other muffin says, "Look! A talking muffin!"

*Bows*