Why does a towel feel different from a smooth bedsheet?

After a bath, a fluffy towel feels soft and a little bumpy against your skin. In bed, your hand slides across a smooth sheet. Why does a towel feel different from a smooth bedsheet?

The answer starts with how people make the cloth. A towel and a bedsheet can both contain cotton, which comes from a plant. Even with the same cotton, fabric makers can give them different surfaces.

First, workers use machines to twist tiny pieces of cotton together into threads. Threads are long, thin strands that people use to make cloth. Twisting holds those little pieces together, making a strand that workers can use.

Next, fabric makers use a machine to cross threads over and under other threads. The crossing threads hold together to make a wide piece of cloth. Workers choose how to arrange them for the cloth they want.

For a smooth bedsheet, fabric makers arrange the threads close together in a fairly flat layer. They leave no fluffy threads sticking up. That gives your hand an even surface to slide across when you snuggle into bed.

Now for the fluffy towel. Can you guess what your fingers would feel if some threads curved up above that flat layer? Your hand would meet lots of tiny raised curves instead of one even surface.

Fabric makers create those curves with extra threads as they make the towel. The curves are loops, little arches of thread that rise up and bend back down. Makers keep the loops attached to the cloth so they stay in place.

Lots of loops stand close together across the towel. When your hand presses them, the loops bend and squash a little. Those raised, bendy threads make the towel feel thicker, fluffier, and bumpier than the smooth sheet.

The loops also help the towel do its drying job. Cotton takes in water, and the extra cotton in those loops gives water more places to go. That helps the towel soak up drops from your wet skin.

A bedsheet has a different job: giving you a comfortable layer to rest against. Its flat surface feels smooth as you move beneath it. Fabric makers arrange the threads differently because sheets and towels have different jobs.

Cotton, threads, crossing threads, then flat threads for a sheet or raised loops for a towel. A fluffy towel feels different from a smooth bedsheet because its loops stick up, while the sheet's threads lie flatter.

Tonight, you can settle against your smooth sheet knowing the tiny thread secret beneath your hand.