By Published: March 1, 2019

colorful soapImage by Devin Sakamoto and Isis Peguero

In Flow Visualization, students reveal the beauty of fluids.

Flickering campfire flames, milk swirling in coffee, shape-shifting clouds: For Jean Hertzberg, they’re stunning visual manifestations of the physical forces governing our world.

Since 2003, the CU Boulder mechanical engineering professor has been sharing her enthusiasm for nature’s beauty by teaching students to reveal the hidden splendors of mingling gases and liquids — and make art of it.

“I wanted to bring that to students so that they could find something uniquely pleasurable,” Hertzberg said of “Flow Visualization,” a fall class she offers that has produced a rich and growing body of artworks, more than 900 and counting.

Some engineers might scoff at making art, but she thinks it’s important.

“[Flow visualization] is fascinating and enriches us,” she said. “It’s a turning of our perceptions outward, and that makes us, I believe, better humans.”

Hertzberg’s own research involves creating 3D models of blood moving through the heart to see tiny changes in flow that can signal health issues. It could help improve medical diagnoses, she said — and “it’s awesome to look at!”

The flow visualization class is wildly popular, and there’s a long waitlist each year. It’s capped at 35 students to leave plenty of time for critiquing art. Students learn to use camera settings, play with light and add dyes to illuminate otherwise invisible fluid flows.

Many of these flows can be created at home — soap bubbles, food dye dropped in milk, water spattering off a spoon. Some students also use laboratory equipment to mix fluids with magnets, mirrors and membranes. In class reports, they describe the dynamics at play in their photos and videos.

Engineering courses tend to have firm instructions and test questions with clear right or wrong answers. But in Hertzberg’s class, which is usually about three-quarters engineering students, she encourages them to follow their interests. “I don’t tell them what to do — I give them resources,” she said.

Owen Brown (MMechEngr’19) used mirrors to highlight the flow of heat rising off a lit match. At the same time, he was taking a course on combustion. “I was able to visualize what I was learning [in my other class],” he said, adding that flow visualization “takes those equations and brings them into the real world.”

Brown said he’s benefited by learning to communicate engineering ideas in an interdisciplinary setting through class presentations and critiques.

For art student Rayna Tedford (MArt’03) the class “fostered a deeper interest in science.” Her work improved her photography, because she learned new ways to create abstract images, she said.

Working in teams with engineers, she added, felt like “we were functioning as a whole brain. … It made me learn to value those types of teams.”

Brown is now captivated by his morning coffee, marveling at the way the dense, cold cream runs down in clear lines through the hot liquid. The ritual drink has become a new kind of experience, a moment of immersion, he said, in “the beauty of the natural world.”

See more flow visualization images online at

In our print edition, this story appears under the title "Blowing the Doors Off." Comment on this story? Email

flowing gas image

 Alex Unger

spiky metallic flowing object

Christopher O'Brien, William Olson, Gamal Elbialy, and Ian Macfarlane

tennis ball galaxy

William Derryberry, Kristopher Tierney

high contrast liquid flow

 Thomas Pohlman, Hans Loewenheath and Grant Boerhave

glue drop flow

Philip Latiff, Adam Sokol, Michael McCormack, Ryan Coyle

rainbow fire

Joseph Hall

spiky metallic flow

Katie Yarnell

cylinder in water flowing

Samuel Ballard

blue smoke flow

Tianzhu Fan

rainbow water crown

Lindsey Yarnell

florescent dye in water

William Vennard

rainbow soap and sugar flows

Dennis Can, Alisen Bol, Fiona Wohlfarth