From veteran to janitor to physicist: how Josh Carroll changed his life with YouTube

Could you learn trigonometry in 3 weeks if your life depended on it?

In this episode of TechFirst with John Koetsier we chat with Josh Carroll, who volunteered with the US Army after 9/11 before he finished high school, did 3 tours of duty in Afghanistan, then came back and worked, among other jobs, as a high school janitor.

In the library of the high school he was cleaning he found A Brief History of Time, by Dr. Stephen Hawking, and rediscovered his love of science. Then he taught himself advanced math via YouTube on his path to becoming a physicist …

Here’s the story on Forbes …

And scroll down to get full audio (subscribe to the podcast), video, and transcript of our conversation.

Listen: from veteran to janitor to physicist


Watch: how YouTube changed this veteran’s life

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Read: Josh Carroll learned trigonometry, calculus, and algebra from YouTube to kickstart his path from janitor to physicist

(This transcript has been lightly edited for length and clarity.)

John Koetsier: Could you learn trigonometry in three weeks if your life depended on it? Welcome to TechFirst with John Koetsier.

So, Josh Carroll volunteered with the U.S. Army after 9/11; he did three tours of duty. He came back and worked, among other jobs, as a high school janitor. Then he rediscovered his love of science and taught himself advanced math — via YouTube — on his path to becoming a physicist. And we’re going to get into all of it. Welcome, Josh! 

Josh Carroll: Hi. 

John Koetsier: Great to have you here. Usually this podcast is about tech news and I’m interviewing tech executives … but I was so inspired by your story I wanted to talk to you. And it really is a tech story, right? It’s kind of self-directed education via YouTube. 

Josh Carroll: Yeah, absolutely. 

John Koetsier: Talk to me a little bit about how you jumped into the reality that you found yourself in. Let’s start around 9/11. You signed up, you did three tours. You signed up right out of high school — before you finished school, correct? 

Josh Carroll: Yes. I technically enlisted in my junior year of high school. I went to basic training over the summer between my junior and senior year, and then dropped out in my senior year, and just went military. 

John Koetsier: I did not have any idea. Now I’m Canadian. I’m in Vancouver, Canada right now. I did not have any idea that that was possible, that you could sign up for the U.S. Army, do basic training and not be finished high school. 

Josh Carroll: Mm-hmm. Yep. 

John Koetsier: That’s shocking to me. That’s … wow. What was your thinking there? Why did you do that? 

Josh Carroll: Well, I had been toying with the idea of joining the military probably for three or four years prior to that. I had an uncle that had served and I looked upon the military fondly. But, and like I said, ninth grade … I watched 9/11 occur live on TV, and that kind of was the nail in the coffin for me. I was like, ‘Alright, I’m going to do this.’

And so, right when I could — right when I got old enough to enlist, right in my junior year — I went ahead and signed up, and the rest is history. I joined the Virginia Army National Guard, knowing that that unit was going to be activated and going overseas on repeated tours, so…

John Koetsier: Wow. Well, thank you for that. And that took some bravery, and I’m sure you went through a lot there. You came back and you hadn’t finished your high school education, you bounced around in a few different jobs, you had basically a 10th grade education … as you looked forward and as you looked, what’s my life going to be like after this, what was your thinking before you kind of rededicated to education?

Where did you think your life was going to go?

Josh Carroll: Well, when I first started, like my first deployment in 2007, I wasn’t really focused too much on anything beyond that. It was more or less get through the next year, get home alive, and then see what happens.

And then after my first tour is when I ended up working as a janitor, and that was sort of where I discovered my passion — or rediscovered my passion — for learning, for science. But I was still in the military and I actually got called up again for two more subsequent tours.

So, prior to being able to commit fully to school, I was just sort of deployment to deployment … trying to think about what I wanted to do and make sure I could get home in one piece, and then figure it out from there.

John Koetsier: And it’s not like you can make long-term plans if you’re in the military, right? I mean, like you’re going to go on a deployment, your life is going to be at risk, and it’s about doing that job and coming back, right? 

Josh Carroll: Yep. You devote a hundred percent of yourself to the mission that you’ve been tasked with, with your unit, and that’s your life. You train every day, and you go over and you do it, and then of course you take it day by day.

While I was in Iraq, especially my first tour in 2007, it was Wild West at that point in where we were at. So it was, very much it was just mission to mission, focus on your job at hand, and get everyone home alive.

John Koetsier: Yeah. So, what made you decide at some point that you wanted to go back to school and you wanted to finish maybe high school, go to college, and become a physicist? 

Josh Carroll: So, when I was a kid, I had always loved space. I loved learning about stars, and that was like, really, it was like one of the things that intrigued me the most. Of course, as a kid, I had no idea that the math and physics required to actually do that professionally. I just liked the way Saturn’s rings looked. 

John Koetsier: Sure, me too.

Josh Carroll: So, when I was working as a janitor, part of my duties was, I was cleaning a library, and in the library was a book section on science.

And one book in particular, A Brief History of Time by Dr. Stephen Hawking, I began reading that every night just piece by piece, and it just slowly started to re-sink in, like just, oh my goodness, I’ve really missed this. This is like, I love learning about it.

And that was also where I began learning how much math and physics played a role in our understanding of science. At that point, again, I was still in military. I had another two deployments coming up. So for me, it motivated me to get back into school, but at that point, I wasn’t — I knew that I had 10th grade level math education. There was no way, I thought, at the time, that I would be able to actually get into any sort of physics program. And so I just began going to school sort of focusing on history, law, and a little bit of biology at that time.

John Koetsier: Interesting you mentioned Dr. Stephen Hawking. I actually interviewed the woman at Intel who built the technology that allowed him to transcribe that book—

Josh Carroll: Wow.

John Koetsier: To basically write that book one letter at a time, with some predictive algorithms as well, so that he could autocomplete words and everything like that. Amazing story there as well. So you went through some of those tours, you had made that decision. And you actually got accepted, I think, to go to school, but you had an obstacle, right? It was trigonometry, right? 

Josh Carroll: Yes. I was going to New River Community College in Virginia, and that was where I was sort of — I had kind of accepted my fate, if you would, about … I wasn’t gonna be able to do astronomy or physics because of the math. And I was doing a general studies, and towards the end of my path at New River Community College is when I decided to just take a leap and say, ‘You know what, this is something I want to do.’

And that’s when I began teaching myself the math — like the math required: some basic calculus and a lot of review of algebra that I hadn’t done in 10 years.

And then the obstacle I think you’re referencing is after I had done all of that, I went and applied to go to Radford University to get into their physics program and found out that I was missing the entire field, the entire course of trigonometry, which I didn’t even know … I didn’t know about it. And so when I went to apply, they were like, ‘Oh, you didn’t take trig, you won’t be able to do our physics program.’

And I thought — and this was three to four weeks prior to the semester starting when I was transferring, where I had to declare a major. So yeah, that was quite the obstacle. 

John Koetsier: That is, it’s interesting because those of us who are self-taught in a lot of ways, or learn things ourselves, we’ll often find that there’s a gap that we didn’t know existed, because we just followed what we were interested in and what we knew about, and didn’t even know that that other field existed.

So you found out that you were missing trig … and you needed it. And basically the semester started three weeks from then, you begged in, you said, ‘I’ll learn it.’ How did you do that? 

Josh Carroll: A lot of long nights. It was a combination, I was basically online learning. I was using videos from YouTube. I’d find articles to read on like the different trigonometric functions and what they looked like graphically and stuff like that.

One of the professors at New River Community College had some online video lectures on trig for a course he taught. So I used that to sort of guide myself, and then whenever — I didn’t have access to ask him questions or anything — so when I would hit upon a topic, a trig function or an operation I wasn’t sure of, I’d go to YouTube, find papers or find a video on someone working through it or explaining it, and then I would backtrack from there to where I was and continue forward.

And basically while I was — I was working as a security guard at the time, and so I would pretty much in between my rounds and stuff, I would just sit there with my phone and just go over trig constantly. At home on weekends I was up late, on my days off, just hitting as much trig as I could, and just trying to learn as much of it as I could. 

John Koetsier: What turned you onto YouTube? Did you just do some searches and that came up? Or did you know that there was a lot of educational content there? What triggered that and what kept YouTube going as a key component of your self-education? 

Josh Carroll: Well, it was kind of a Google search thing. I was like, you know what? I need to learn calc. And doing it, putting in trig and stuff, and doing it just from a textbook without an instructor, without an expert there to help guide you through the textbook, show you where to go first and last, kind of like to help structure your learning — textbooks can be kind of abstract.

With YouTube, it’s very much, the topic that you need is right in front of you and they’ll go over things.

And of course for me, it was the same sort of, I guess, methodology where I would follow the video on YouTube or I’d Google something. And a lot of times it would link to YouTube — like Khan Academy and PatrickJMT, just to throw out a couple of YouTube names — it would link to their videos, so that’s kind of where YouTube became a staple in my mathematical diet, if you will. And then whenever I would hit something that was a barrier, something I didn’t remember or I’d never seen, I would then search that in YouTube and it would find video series on that topic, and I would just [go] down the rabbit hole until I figured it out. 

John Koetsier: That’s a good rabbit hole to go down! A lot of people go down some bad rabbit holes on YouTube. But how did that work? You basically, then you went to Radfield — I think I got that name right. 

Josh Carroll: Radford University.

John Koetsier: Thank you. And did you learn trig well enough to go into the first few courses and exceed expectations? 

Josh Carroll: I guess so. I got the degree. I was terrified, because I didn’t have a formal stamped education saying that I knew it. I didn’t have tests or grades or professors that said, ‘Yes, you’re good to go.’ It was just kind of on me.

So when I showed up for my first course in calculus, or my first course in physics, and you see those trig functions appear on a homework, you know, there it is: sine, cosine, tangent sitting there inside of a math equation, and you just kind of have to roll with it. And it was terrifying and exhilarating, but it was, I taught myself — there were still some gaps. There was still some stuff at that time that I just didn’t know the rules, because I never had to apply them before.

So it was also a lot of on-the-job training sort of a thing, where I would answer the question and then I’d ask one of my classmates, ‘Did I do this right?’ And they’d be like, ‘No, you need to do this with the sine function’ or something … I was like, ‘Oh, I didn’t know that.’ [laughter] Probably carry on my own, do my own thing until I figured it out. But it all came together in the end … I’m pretty decent at it now, I guess. 

John Koetsier: Don’t tell anybody, it’s a big secret, but some people who go to school for these things and get the official piece of paper that says they know X, often don’t know X either. So [laughter] they skipped that class or they — whatever happened, they didn’t learn it.

What’s interesting when I hear that, is that we’ve seen over the past couple years, major tech companies like Facebook, like Google, like Twitter, say, ‘Hey, you actually don’t need the degree to apply. We’ll actually take what experience you have and look at that on its own merits.’ I remember that I hired — I believe he was 19 at the time — I hired a 19-year-old developer, literally, obviously hadn’t gone to college or university, but he knew his stuff. I mean, absolute whiz, you know, absolute self-taught genius, right, and did a ton of work for me.

That is something that — I mean, obviously going to school is great — but there was something different in what you did, and yet it was successful. 

Josh Carroll: Oh, absolutely. I’m a big proponent of what I call the “democratization of learning,” the decentralization of certain skill sets that you can learn, especially with computer science and coding, there’s so many things out there. It’s a culture in computer science and coding. There’s GitHub and there’s online resources you can go to and absolutely pick skills up without the degree stamp.

Now, I’m not advocating — if you have the ability to do school and to learn from experts, obviously go that route. But like for me, I didn’t have specific access that other people did, so I took another route. But if it helps promote the idea that you can gain knowledge from different avenues, different ways of doing it, then absolutely go for it. 

John Koetsier: So what’s the result? Where are you now? What are you doing? And where are you going?

Josh Carroll: So I currently work. I work as an engineer for a consulting firm — that’s my day job. And then I’m also going to grad school at the University of Utah. I’m studying applied mathematics, computational science. 

John Koetsier: Cool.

Josh Carroll: So I’m getting to continue the math education, which is — if you would’ve told me a few years ago, back when I was trying to teach myself trig that I’d be in a graduate program for math, I would have laughed at you. 

John Koetsier: [Laughter

Josh Carroll: Yep. I want to continue with math education. I want to be able to promote being able to take a subject, maybe something as daunting as mathematics appears and you can absolutely break it down. And I mean, I did it … I broke it down for free. I just used YouTube. 

John Koetsier: Yep. Yep. What does that say, we often get worried — those of us who study the future, look at automation that’s happening, self-driving cars, robots, and other things like that — and we think, hey, you know, the jobs that are coming are going to be up-skilled jobs, and if there’s no more need for truck drivers in 10 years or 15 years, or there’s a vastly reduced need, what are those people going to do?

What does your experience say about the ability for people to retrain and relearn and maybe aim for something different? 

 Josh Carroll: Well, it’s going to be a reality we have to face. There’s no slowing it down. I mean, automation, self-driving cars, things like that … it’s not only cheaper in the long run for companies to move to this route, it’s usually safer, it provides better planning for their business, and so the market will go where the market goes.

And it looks very strongly that it’s going to move towards — jobs that typically don’t require a formal education, or technical skills such as computer coding, such as truck driving and things, whereas as vital and essential as these jobs are, they’re going to be lost, they’re just going to go away. So, being able to retrain, or find a new niche, something that you can call your own and be good at is going to be vital for people as we move forward.

And I’m sure many avenues of that conversation …[chuckling & crosstalk]… but yeah, being able to learn something new and devote yourself and do it — something that you’re passionate about — I’d say in the next 20 years or so, that’s going to be vital.

John Koetsier: Absolutely. If only everybody could be doing something that they’re passionate about, that would be a wonderful world.

So TechFirst, this podcast, is about tech that’s changing the world, innovators who are shaping the future. And as I mentioned off the top, usually I’m interviewing tech execs, usually there’s a news component or whatever. This has been a bit of a different story, but what does your story tell us about education? And maybe what’s the message for other people who might feel stuck in a job that they’re not passionate about, that they feel like is not using all their potential? 

Josh Carroll: Well, I mean, given platforms like YouTube and Khan Academy and these resources you have — again, for me, it was math. That’s not everybody, and I’m sure it’s different for different subjects, but for jobs like coding, mathematics, science jobs that require these technical skills, the knowledge is there.

It’s not always easy to digest, but again, for myself, it was just a matter of disciplining myself enough to sit down and devote that time on the internet, looking at these videos, teaching myself, testing myself. It worked out for me, it helped. And I know that not everybody learns the same way. And so I feel the more modes that we offer education to the people in general — again, this decentralization of this authority of information— you know, that is I feel like what’s best for society, especially when it comes to the sciences, the mathematics, things like that. It’s just, it’ll be vital, as we just discussed, it’s going to become very important very — it already is, but, yeah. 

John Koetsier: Yeah. Very, very interesting. Josh, I want to thank you for sharing your story, and I just want to congratulate you. It’s a wonderful story when somebody finds their passion, and not only finds their passion, but then finds the discipline to continue with it. Because we often find, all of us find things that we’re interested in and we always want to do something, but having the discipline to actually make it happen over time … that’s another level yet. Congratulations. 

Josh Carroll: Well, thank you for having me. 

John Koetsier: Well, thank you for joining us on TechFirst. For everybody else as well, thank you for joining us on TechFirst. My name is John Koetsier, I appreciate you being along for the show. You’ll be able to get a full transcript of this podcast in about a week at You’ll see the story at Forbes shortly thereafter. And the full video is always available on my YouTube channel. Thanks again for joining. Until next time … this is John Koetsier with TechFirst.

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