December 12, 2003

 
What's inside an Etch-A-Sketch?

Sometimes our curiosity is challenged by a question that only the most patient, methodical and painstaking approach can hope to answer. If the question is compelling enough, the necessary discipline and resolve can be found in the youngest scientist.

Or, to put it another way...please, oh please, oh please god tell me that I'm not the only pathetic little monkey who burned several days of precious childhood obsessively drawing away the entire silver surface of an Etch-A-Sketch to get a look at its innards.

An Etch-A-Sketch®, for foreigners and other ignorant people, is a plastic box filled with aluminum powder and bits of plastic. When you shake it, the powder sticks to the underside of a glass viewing panel, forming a silvery gray coating. Knobs on either side of the box scrape the powder away from the glass(side-to-side or uppy-downy, depending on the knob) in one continuous transparent line, which looks dark against the lighter gray.

Elaborate, if ephemeral, drawings have been executed in this way by dedicated aficionados who clearly have something very seriously wrong with them.

But...how does it work? If you make drawings with large dark areas (which are made by drawing lines very close together), you get tantalizing glimpses of the machinery inside, until your brother grabs it and shakes it just like he always ruins everything and it's not like your parents are ever going to do anything about it but thank goodness you're all grownups now and you don't have to spend any more time together than absolutely necessary and, geez, that last time he looked like he was one Ding-Dong shy of a massive coronary, like he's never heard of blood pressure or something?

Anyhoo.

 

 

The best way to get a good look at the works is to scrape away all the aluminum powder, which is accomplished by drawing a line across the screen, moving the stylus down ever so slightly, and draw the line back across. Repeat, as necessary. For several days, at least. This is the part where it's helpful to be mentally ill, or at least clinically obsessive.

The result, roughly, is what you see at right. The knobs turn a complex pulley system (which I couldn't make out very well). These wire pulleys (I wonder if they're nylon or something now?) move two rigid metal rods, one for the vertical and one for the horizontal. Poised in the middle is the stylus (wot does the scraping). The rods run through the stylus, one above the other. As the rods move back and forth, the stylus slides along them. Why it slides along so smoothly is beyond me — perhaps the aluminum dust acts as a lubricant.

Then the result of so much painstaking labor sits on a table in your room, well away from brother, mocking you with its fragility and impermanence, daring you to snatch it up and give it a good shake and wipe away all those painful hours of concentration and effort with one wild gesture, much the way standing on a rooftop near the edge makes you want to launch yourself straight over the side and into oblivion like a great reckless doomed pink arrow. Only, obviously, not so dangerous.

A note to British readers:

aluminum = aluminimnium
 

It has come to my attention that some bad, wicked monkeys have discovered the secrets of an Etch-A-Sketch by taking one apart. What kind of clumsy, inelegant, lazy, effortless, stupid pretend science is that, anyway? Such antics bring shame and dishonor to pretend scientists everywhere!

 

    < alley oop!

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