Paper

Paper is a thin mat of plant fibers bonded together. It is light and cheap, soaks up liquids and can be made in almost any thickness, which is why it turns up in surprising places, including inside electronics.

The fibers are cellulose, usually from wood. Logs are chipped and cooked in chemicals that dissolve lignin, the natural glue holding wood together, leaving loose fibers called pulp. The pulp is beaten and mixed with lots of water into a thin slurry, then sprayed onto a moving wire mesh. Water drains away, rollers press the wet mat, and heated cylinders dry it. As it dries, the fibers grip each other through hydrogen bonds, so no added glue is needed.

In a TV, a very pure, thin grade of paper sits between the foils of each electrolytic capacitor, keeping them apart while holding the electrolyte. In a speaker, pulp is formed on a cone-shaped mesh instead of a flat one, making a cone that is stiff and light enough to push air quickly. Papermaking is traditionally credited to Cai Lun in China around 105 CE, though earlier forms existed.