A lot of people don’t believe me when I tell them this, but I truly don’t understand how water crawls up a paper towel or string or piece of cloth. How does it get the energy to do this when it’s just sitting there; and the towel is also seemingly passive in the whole affair?

I’m a physicist and I work with many like-minded scientists. When I ask them about this phenomenon, they realize that it’s not all that simple, but probably it has something to do with electric forces in the towel and interactions with the water. I’m sure that this is part of the answer. But even so, I’m happy to admit that I don’t really understand it.

So, I assign the problem to my students and ask them to start to investigate different features of liquid absorption. They think of much better investigations than I would, and when we share these we start to come up with more ideas. To get them started, I’ve created this timelapse video of water moving up a cloth:

I thought my idea to speed up the video and include a clock in the frame was clever. I’m proud of that old-school technique.

What do you notice? What wonders strike you? What investigations could this spur? This is just the beginning.

Here’s what the scene looked like the following morning:

And then, later that morning, I detached the cloth and set the loose end on the table. It was originally dry, but then this puddle started to form:

Epilogue

In my classes, I see lots of really great examples of how this phenomenon can be turned into a research project with lots of different variables. Researchers create all sorts of different investigation designs with interesting variables and creative methods. This time-lapse video that Micah created gives a good impression of one of the hundreds of ways the climbing fluids can be studied, and it’s fun to see the process overviewed in just a couple minutes: