How do paper towels soak up water so quickly?
asks a reader. We’ve all seen water rush into a paper towel, as if toward a long-lost friend. And in fact, it is the sweet nature of paper towels that leads to the instant attraction. Paper towels are really perforated sheets of sugar molecules. But if you’re tempted to take a bite out of your Bounty, stop right there. The sugar molecules are linked up into giant cellulose molecules. The average cow or goat can digest cellulose, releasing the carb-y goodness. But we humans can’t. To us, cellulose is fiber, good for making us feel fuller and moving things through the intestinal tract. (And now you know why goats happily chew random bits of paper. To Bill the Goat, it’s a delightful snack.) Cellulose is the carbohydrate that most plants are made of, and most paper towels are made from trees. Cellulose fibers are composed of giant molecules called polymers. The individual sugar (glucose) molecules in the polymer chain are called monomers. And it’s the attraction between sugar molecules an
