The PhD Student's Knitted Sweater Visualizes Research on Freezing Drops

Erik Fagerström, a PhD student at Luleå University of Technology, has taken an unusual and creative approach to explain his research on freezing water droplets. By knitting a sweater that visualizes his scientific experiments, he aims to make his work more accessible – while also challenging his own craft skills.

"I’ve done some work visualizing my droplets for posters and articles, and the idea of a sweater came up as a fun thought. I figured I could take images from my experiments and translate them into a knitting pattern," Erik explains.

Erik’s research focuses on understanding the internal flows that occur in a water droplet as it freezes.

"When a droplet falls onto a cold surface, it starts freezing from the bottom up. During the freezing process, two different flows occur inside the droplet: first, the liquid moves down along the surface and up in the center, then the flow reverses. I want to understand why this reversal happens and what thermodynamic mechanisms drive the flow."

Making a Complex Process More Understandable

On the sweater, Erik has visualized the different phases of the experiment.

"The first row shows a droplet that has just been released. Then you see how it lands, spreads out, and starts freezing. With each section of the sweater, the freezing front moves upward until the droplet is fully frozen with a characteristic pointed tip," he says, explaining that the sweater helps make the complicated process more comprehensible.

Colleagues at the university have been impressed with Erik’s creative interpretation.

"I’ve received many great comments about the sweater – that it’s a fun and nerdy idea. Some have also pointed out that I might have a hard time letting go of work even in my free time since I knitted the sweater during a vacation."

Erik, who already had a solid foundation in knitting, wanted to challenge his abilities by creating his first original pattern.

"It was a challenge to convert scientific concepts into yarn and needles. The hardest part was probably planning how the details would come through with the right yarn and colors."

Combining scientific knowledge with craftsmanship

Although knitting hasn’t directly helped Erik in his research, it has given him new ideas for presenting his work in a different way.

"It’s been a great way to explain to friends and family what I do. The sweater makes it easier to show step by step what happens to the droplet."

For Erik, knitting is not only a creative outlet but also a way to relax from the intense life of a researcher. He enjoys combining his scientific knowledge with a hands-on craft and is already thinking about future projects.

"Right now, I’m working on a sweater with different animal patterns to get better at creating designs with more colors. But who knows – maybe there will be a second version of the droplet sweater with more details this fall," he says with a smile.

• Fluid mechanics