Sweet Science

If you’ve ever been to a baseball game, a fair, or an amusement park, then you’ve probably snacked on cotton candy—a classic summertime treat. But what exactly is this yummy concoction on a stick? The answer: It’s almost pure sugar. Yet cotton candy looks nothing like the grainy white stuff you’d find in a sugar bowl. That’s because it undergoes a transformation while being heated and spun to achieve its cloudlike texture.

Have you ever been to a baseball game, a fair, or an amusement park? Then you’ve probably snacked on a classic summertime treat. It’s cotton candy! What exactly is this yummy creation on a stick? The answer: It’s almost pure sugar. But cotton candy looks nothing like the white grains in a sugar bowl. That’s because it’s been transformed into a cloudlike form. This happens as it’s heated and spun.

Making cotton candy requires a special machine invented more than 120 years ago. The device consists of a metal cup with tiny holes that sits in the center of a large metal bowl. A person fills the cup with granulated sugar and turns on the machine. A heating element warms the sugar until it melts. “It goes through a change in its state of matter, from a solid state to a liquid state,” says Tami Lasseter, a chemistry professor at Portland State University. “Chemists call this a phase change.”

Next, the cup begins to rotate super-fast, spinning the molten sugar inside. This circular motion pushes the hot liquid out through the cup’s holes. The liquid sugar sprays out in thin streams and instantly cools upon contact with the surrounding air, solidifying into thousands of wispy strands. The fine threads accumulate in the machine’s bowl. Then a person swirls a paper cone or stick through the sugar strands. Once they’ve gathered a huge pouf, it’s ready to be served up to kids eagerly waiting for the tasty treat.

To make cotton candy, you need a special machine. It was invented more than 120 years ago. The device has a metal cup with tiny holes. This cup sits in the center of a large metal bowl. You fill the cup with grains of sugar and turn on the machine. A heating element warms the sugar until it melts. “It goes through a change in its state of matter, from a solid state to a liquid state,” says Tami Lasseter, a chemistry professor at Portland State University. “Chemists call this a phase change.”

Next, the cup begins to spin really fast. It spins the liquid sugar inside. This circular motion pushes the hot liquid out through the cup’s holes. The liquid sugar sprays out in thin streams. When it touches the surrounding air, it cools instantly. The sugar changes into thousands of solid, thin strands. The fine threads collect in the machine’s bowl. Then you turn a paper cone or stick through the sugar strands. When you have a huge puff, it’s ready to serve to kids waiting for a treat!