Ever wanted to know how an Etch-a-Sketch works? I always assumed that I was drawing with iron filings, or something else that would be attracted to magnets (sort of like those little things where you use a magnetic wand to draw “hair” on the bald guy). Apparently it isn’t drawing, but actually scraping off, which would explain the “etch” in the name. Here is the explanation of how it works from Mental Floss.
When you turn the Etch A Sketch upside down and shake it, the inside surface of the screen gets coated with aluminum powder, which will stick to almost anything (mixed in with the powder are small polystyrene beads, which help it flow evenly and keep it from caking).
Also inside are horizontal and vertical bars connected by thin steel wires to the knobs on the face of the toy. A stylus is mounted where the two bars cross, so when you turn a knob, it moves its bar and the bar moves the stylus. As the stylus moves across the inside surface of the screen, it scrapes off the aluminum powder and creates a dark line on the light gray screen, which is just the darkness of the toy’s interior set against the lighter aluminum powder.
To erase their picture, an artist only needs to flip the toy and shake, redistributing the powder over the screen.
The blogger in me wants to make a deep point about how this is like God scraping off the parts of your life that don’t glorify Him, but it is really just the opposite of that so I will just say that it is cool to know how the magic happens sometimes.
You can read the complete article at http://www.mentalfloss.com/blogs/archives/77624