Why this lab studies the speed of bug pee and other curiosities

What do the hydrodynamics of insect pee, $1 hearing aids, and squid robots have in common? A lab organized around curiosity, not disciplines.

• 0:02Speaker 00

  Hey, I'm Flora and you're listening to Science Friday. In a lab in the Rocky Mountains, you can find a group of scientists, hard at work, trying to find answers across biology, physics, and engineering, from the hydrodynamics of insect pee, to the physics of sheepdog herding, to designing robots that resemble squid and hearing aids that only cost a dollar. These questions may seem unrelated, but they're glued together by one scientist's philosophy about how science should run and how to make the most of the lab's time. Bioengineer Dr. Saad Bamla runs the Bamla Lab at the University of Colorado Boulder. Saad, welcome to the show.

• 0:44Speaker 01

  Thank you, Flora. Happy to be here.

• 0:46Speaker 00

  I want to give people a flavor of your work, so let's start with insect pee. Why did this particular question whet your appetite?

• 0:54Speaker 01

  Um, where do I start? I was initially interested in how the sharpshooters actually suck the fluid out from the trees, the xylem fluid, and I thought it was a great fluid dynamics problem. And as I was watching this bug, I quickly realized it was constantly peeing, like these most perfect spherical droplets. It's like the most beautiful pee in the world. And I was like, all right, what goes in must come out and let's see what's on.

• 1:30Speaker 00

  I guess it's on an all-liquid diet, right?

• 1:32Speaker 01

  It is. Yeah, it's basically feeding on water, so it has to constantly feed and then constantly pee. I think as with most of the questions that we kind of go on these rabbit holes and adventures on, it wasn't clear to us. We were just kind of poking around and we made some high-speed videos and I wanted to understand how it was flicking these droplets. And the initial thought would be that it would be kind of the simple study. And this is where it got interesting because one of the PhD students, one of my first PhD students in the lab, Elio Celita, when he was analyzing the data, he kept telling

• 2:13Speaker 01

  me that the droplet was moving in air faster than the stylus, which is the kind of object that was kicking the droplet. And I just didn't believe it because it didn't make sense. If you threw a baseball and in air you measured the speed of the baseball as 100 miles an hour, but if your finger that was flinging this baseball moved only at 50 miles an hour, it just wouldn't make sense. Where would that extra speed come from? And that was the puzzle.

• 2:38Speaker 00

  What'd you find out?

• 2:40Speaker 01

  We, after figuring out that we were indeed recording everything correctly and there was no mistakes in our MATLAB scripts as we were analyzing any factors missing, we realized that unlike a baseball, which is rigid, the droplet is squishy and the surface tension was acting like a spring and storing energy. And this bug was timing it such that additional energy was stored in the deformation of the drops and it was giving it a boost and we called it super propulsion. And I think that made it even more interesting because it gave us a principle out of it that we could now use in engineering systems.

• 3:22Speaker 01

  And that was so satisfying, but it wasn't planned at all.

• 3:26Speaker 00

  But why do insects need superpropulsive pee?

• 3:29Speaker 01

  So it's because it's feeding on xylem sap, so after photosynthesis, it's rich in sugars. And so these bugs, the sharpshooters, are feeding on the xylem, which is a very frugal diet. It's as if you and I would just survive on diet soda all the time. We would have to drink a lot and we'd have to conserve our energy to do all the other things a living system does, mating, moving around, flying. And so if they can save energy in any aspect, especially one that they're doing over and over and over again, so if you watch this bug, it's constantly peeing like this, it's going on. So during super propulsion, what it allows it to do is save a little bit of energy because it's storing energy in the surface tension, the droplets, so it gets some kick for free and it can fling it away farther.

• 4:14Speaker 01

  Otherwise, those droplets, if they don't go as fast and as far, will contaminate either the organism itself or its friends, which are all feeding together and collect in a pool. And biologists and ecologists hypothesize that it could attract predators.

• 4:30Speaker 00

  Fascinating. I mean, so this is one example of one study, but you study so many things. When we met recently, you were telling me about research about music, which feels, you know, completely unrelated, and I know that's in early stages, but what's the question you're tackling?

• 4:48Speaker 01

  Um, I think with all of these things, it's, sometimes I feel like Alice in Wonderland. We're basically taking kind of this meandering walk and, you know, smelling a flower here, observing a patch of moss somewhere else. And the goal always is we're keen, kind of, I feel like I have the superpower with my glasses. I can look at a system and try to uncover some of nature's secrets, some principles. In any case, so the music is one stop in this journey, where a phenomenal postdoctoral researcher in the group, Dr. Luis Gonzalez, basically asked this question, is if you

• 5:32Speaker 01

  listen to Mozart's Symphony or any piece of music and you listen to it as it's intended, it sounds melodious, harmonious, but what if you played it backward? It just sounds off. And so why does it sound off when you play it backward? And so encoded in there is the arrow of time. And so we're starting to ask, from the laws of thermodynamics, can we ask, how is time encoded in pieces of this music?

• 6:01Speaker 00

  How is time encoded? It's such a deep question and it's an astrophysicist, right, who's taking this on?

• 6:08Speaker 01

  That's right. And so we're so well-suited in 2026 to attack a problem like this, just because we have access to tens of thousands of pieces of music going back almost six centuries, from Gregorian chants to classical pieces, to Beatles and Star Wars theme music and, you know, more contemporary pieces of music, including jazz. And we can ask, why do different composers, why do different Western music genres have different tonalities? And analyze it through kind of this lens of statistical physics or thermodynamics. And we're asking if we can kind of extract a law of this cultural artifact, which is music.

• 6:52Speaker 01

  Is Western music similar, like Indian music or Iranian music or, you know, Chinese music? And how did we all come to share? How do we all figure out that we can all listen to certain types of beats and certain intervals? And there is something in our neurons that helps us appreciate music in a certain way? What is that basis? What is that neural thing? And is it different if I'm trained in Western music versus if I'm trained in Persian music? And so the problem is these things are so subjective and we're trying to quantify it and find some variables that give us an imperfect, yet a hook and a grip onto this problem that satisfies us a little bit.

• 7:36Speaker 00

  This Alice in Wonderland approach to science, you know, working across many disciplines, stopping to smell the flowers when you feel like it, isn't the norm. It's not exactly the traditional path, or maybe even so encouraged. Do you ever get side-eye?

• 7:55Speaker 01

  I get a lot of side-eye and I don't know whether it's, I think somebody, I think jokingly asked, well, who gives you permission to do whatever the heck you want? I said, well, nobody, you don't need permission. I give myself permission. And often I find as humans, as scientists, it's not as if there are rules to tell us how we should be. I think some of it is self-inflicted, self-imposed. I remember a mentor, I think a well-meaning mentor, because I'm trained as a chemical engineer, they said, Saad, you should study these classical chemical engineering topics

• 8:37Speaker 01

  of fluid mechanics and colloidal matter and soft matter, so then you can get tenure over five years. If you go and study in the Amazon these spiders, you're not going to get tenure. And I, even though I was young, I kind of knew that taking risks and kind of finding your taste of science and finding kind of what smells right to you, it's a muscle. It's not, it cannot be dormant for five years. It's like going to the gym and even though if you go to the gym and the next day, it's not as if you can see yourself stronger, but you nonetheless keep going to the gym and you have to do it repeatedly, over and over again. And it's a muscle, risk-taking, and finding new ways of looking at things. You can't just wait for tenure to do it.

• 9:22Speaker 01

  And I observed, I think, some of these well-meaning mentors, after they got tenure, I think they continued doing what they were doing. And I, I think it's a little bit of loss for science and the next generation because they perhaps censored themselves and, yeah. Anyways, my, I feel that we have a short life and I'm very fortunate to have been given the gift to kind of explore and it's a shame if I don't.

• 9:52Speaker 00

  Where did that philosophy come from in you?

• 9:58Speaker 01

  I think maybe there are two strands. One is more of a humanist strand is I never thought I'd be a scientist and I I didn't know what I wanted to be. And so I feel very fortunate that I can do this as an adult because I didn't have this opportunity to play as a as a child. And so I want to make the most of it because I never dreamed I could do this. So I feel so lucky to be able to derive joy from observing these kind of simple things. And and so I just have to do it just because I feel so grateful to be alive every day. And I can't believe my luck.

• 10:42Speaker 01

  And I think the second thing is that because I'm an engineer, I naively thought when I did my PhD, that if I built technology and I would earn money, that would bring me happiness. And I had the opportunity to translate my technology. And I remember sitting in a parking lot with a check after I had sold and installed this instrument to a Fortune 500 company. I felt so empty and hollow. And I realized that zeros on a check did not inspire me. Like, I thought money was great, but it's actually, we just need to have enough of it. After that, this is, this is such a gift. It's just such a, I think it's priceless to be able to uncover kind of the secrets of the universe. And I feel like I have a superpower and I don't know what else to say.

• 11:28Speaker 00

  Yeah, I mean, you know, I think people sometimes describe this mentality as childlike wonder. And as you just said, you didn't have that opportunity as a child. And I know that from watching a talk that you gave. Would you feel comfortable talking about that and how it relates to what you do now?

• 11:46Speaker 01

  Yeah. So I, I lost my mom very earlier on. And I think with anyone who's lost a parent or a close family member at a very, very young age, I think I was 12 or 13, my mind kind of blocked out a lot of things just to protect this young mind from this trauma, from this grief. And it took me a while to kind of find myself and came in young adulthood when I found myself in Madagascar for field work. And I kind of felt like, you know, the cloud lifted and the darkness kind of, my eyes opened up and I could see things clearly.

• 12:31Speaker 01

  And so, I don't know. I, I know for a long time I used to feel like life was unfair because I had to go through this trauma and grief. But I'm a big believer that I think whatever happens, it shapes us. And so, in any case, I get to, I get to see the world with new eyes. And yes, oftentimes I get to do childlike things as an adult, get paid, get paid to do it. And I'm obviously much smarter, have better skills. I can lead my team and hopefully make it into useful things that others enjoy or uncommunicate that, so.

• 13:10Speaker 00

  And you have the courage, you've, you've found the courage to give yourself permission to do that.

• 13:14Speaker 01

  Yeah.

• 13:15Speaker 00

  Which I don't think is trivial. Okay, we have to take a break, but don't go away because when we come back, I want to know how you know if a question is good.

• 13:24Speaker 01

  Of course.

• 13:25Speaker 00

  Stick around.

• 13:34Speaker 02

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• 14:09Speaker 03

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• 14:44Speaker 00

  Okay, Saad, how can you tell if a question's a good question to tackle scientifically?

• 14:50Speaker 01

  I think it's like piece of art if somebody writes a poem or somebody paints a painting or even, you know, composes a piece of music. How do you know it? Of course, just like, you know, filmmakers can take classical pieces and make it palatable to modern tastes and make it a blockbuster such that maybe that inspires people to go read classical literature, there is a way to think about science that we know can be made palatable to everybody. And, you know, we're scientists, we're pretty smart. We know what can be catchy and what can be attractive and package it, just like all artists, you know?

• 15:29Speaker 00

  Insect pee, obvious, grand slam.

• 15:34Speaker 01

  But I think you also know there are some things that are your own taste. It just gives you so much joy. Sometimes I feel it in my, deep in my stomach. I feel this giddiness and I, I just know it feels so good. And what is it? It feels like, for a brief second, it feels like you know something that nobody on the planet knows and nobody ever who lived ever knew it the way you did. You kind of uncovered a secret. It was there. You just, you know, made the final brushstrokes and you uncovered this fossil, new interesting tidbit, a new way of thinking. And then, yeah, how do you know? I don't know. It just comes and it smells good and it feels good.

• 16:18Speaker 01

  It's just so great. And then sometimes people appreciate it, sometimes don't. But I think I tell my team members, it just takes two to think. And if them and I care about it, that's enough. We don't need the world right now to care, but we'll polish it and we'll make it pretty and we'll share it with the world. But for a long time, for a year, three years, five years, it's just a journey that me and a team member, one or two people will go on and we are exploring. And it's just the most amazing thing. And what else? I don't know. You'd have to, I'd pay a million dollars to be able to do this. It's just, it's just a delight. I don't know any other way.

• 17:00Speaker 00

  I know you're a parent because we talked about this. Have you noticed anything about how your kid approaches? Kids, maybe, kids.

• 17:09Speaker 01

  Two boys, six and two.

• 17:10Speaker 00

  How your kids approach, you know, science or school or the natural world that stands out compared to your childhood?

• 17:20Speaker 01

  Gosh. So my older one, I took him to the Amazon with me and, you know, he caught snakes, scorpions, bullet ants. And, you know, for a five-year-old to be on the Amazon, there'd be times he'd be sitting on this huge mound of leaf cutter ants and he'd, it'd be 3 AM. And he'd be like, no, no, I just want to be here because he's, you know, poking and prodding these leaf cutter ants that are just going about their business. And it was heaven for him. I couldn't get any research done because I was just worried he'd die. He's constantly telling me that he's an artist scientist because my wife is an artist. And we're in Colorado now and bears are basically terrorizing us every night up in the mountains.

• 18:05Speaker 01

  And he's like, but dad, we need to set up cameras. And then what are they like and what are they not like? And he's like, maybe we can make a trail and leave the honeypot there. And if you give them food, they won't bother into our trash can. It's like coming up with all these experiments. And I just love it. I just love that he can see the same thing I see. Hey, there's an interesting puzzle here. And isn't that amazing to see puzzles everywhere? It just, life just seems like an endless string of puzzles and it's just fun games out in the backyard.

• 18:38Speaker 00

  Saad, thanks for joining us today.

• 18:40Speaker 01

  Thank you, Flora. Thank you so much for having me. I really, really enjoyed our conversation. Yeah.

• 18:45Speaker 00

  Me too. Dr. Saad Baumler, bioengineer at the University of Colorado Boulder. This episode was produced by Dee Peterschmidt. If you liked listening, why not leave us a review? Here's the one we got from bothered2020 on Apple Podcasts. They write, I love the show, the episode on beavers. I'm now obsessed with beavers, lol. You too, bothered, that beaver episode got me too. And if you're out there listening and you feel newly obsessed with glasswing sharpshooters and their super propulsive pee after this interview, why not leave us a review? Thank you for listening. I'm Flora Lichtman.