Inside an Etch-a-Sketch, a thin layer of aluminum dust coats the inside of the screen. Turning the knobs moves a stylus that scrapes off the powder to draw lines, and shaking the toy scatters the aluminum powder again to erase the picture.
Aluminum is a lightweight metallic element that resists rust and spreads easily when ground into powder. Its fine, silvery particles help create the erasable drawings inside Etch-a-Sketch toys.
