Deep Dive
Shownotes Transcript
Do you want to spend another summer stuck at home? Hey, Jim. How's your back? Uh, you know. I hear ya. Leave the small talk behind because Disney and Pixar invite you on an out-of-this-world adventure. Engaging hyperspeed. This is them! On June 20th. Welcome to the community. Prepare to be conquered! But I just got here! Follow me. What is this place? These are the lava tunnels. I am not
Disney and Pixar's Elio in theaters June 20th. Tickets available now. Rated PG. Parental guidance suggested. Hi, friends. If you love Brains on Universe, you'll love the latest season of Million Bazillion, Marketplace's award-winning kids podcast about money. Hosts Ryan and Bridget answer the funny, tricky, and just really good questions from kid listeners to help dollars make more sense.
Million Bazillion is presented in partnership with Greenlight, the debit card and money app for kids and teens. With Greenlight, kids and teens learn to earn, save, spend wisely, and invest. Learn all about Greenlight at greenlight.com slash million. And tune into Million Bazillion wherever you find your favorite podcasts. From the brains behind Brains On, this is Moment of Um. Um, um, um, um, um.
Moment of Um comes to you from APM Studios. I'm Sandon Totten. Ugh, this stoplight won't change. And I'm running late for my nose haircut. Come on, turn green. Green, green. I feel like I've been stuck at this intersection forever. Look at all those other cars driving along so smug with their green lights. When will it be my turn? Hmm.
What if I try flattery? Hey Stoplight, you know red is so out right now, ew. But, say, have you tried wearing green? I bet green is totally your color! Oh my gosh, you'd be such a trendsetter, so just turn green now. Ugh, nothing! Time to change tactics.
Using the awesome powers of my mind, I will you to change your light to green! Still red? Ugh, come on! What am I not getting here? Why won't the light change? I bet Lucy and Margaret are also running late for their nose hair trimming appointments because they asked us this: What makes a stoplight change colors anyway? Better phone an expert for this one.
I'm Jerry Kotsmacher. I work for MnDOT or the Minnesota Department of Transportation. MnDOT operates 1,300 signals. There's probably about 5,000 signals throughout the state of Minnesota.
So stoplights know when or how to change by loop detectors in our roadway. What is a loop detector? Under the roadway there's loop wires that are built into the road system. They detect the vehicle mass or steel in the vehicle.
and change the light to green. A lot of people think that weight is what will detect a vehicle, but it's more of the vehicle mass, the steel in the vehicle, changing the inductance of that particular loop, which then puts a call into the controller. A call is a message that gets sent to the controller, which then changes the signal to green.
If a car doesn't get a green right away, it could mean that there's just heavier traffic on an opposing approach.
which means that grain gets extended by the detector. We also use cameras for detection. So the camera will typically be on the arm of the traffic signal where the traffic signal heads are. There are some stoplights that are just on a timer and we call that a fixed time signal. So there's no loop detectors on any of the broaches.
So for a fixed time signal, we'll give 30 seconds of time for one approach and perhaps 45 seconds for another, depending upon the number of vehicles on that certain approach. Um, uh,
Huh. So under my car right now, there are wires running underneath the road. They detect my car, not by how much it weighs, but thanks to the material in my car. You see, those wires, they have tiny electrical currents in them. And the metal in my car messes with that current. When that happens, it sends a signal to the stoplight to let it know to change. Smaller vehicles, like bicycles, can have trouble triggering that change because they have less metal in them.
But sometimes, even if your car sends a signal to the light, it can take a while for the green to come on. Because there might be a lot of traffic going the other way. Oh, and speaking of which, it's finally green! Better get a move on it. Don't want to miss my appointment at Schnauz Snips. My nose hair is so long. I can't wait to get a fresh trim. It's going to feel so good.
If you like this episode, take a second to subscribe to Moment of Um wherever you listen to podcasts. And if you like cars, check out the Brains On podcast where we have a whole series about the science of automobiles. Want to see our shows come to life? Head to YouTube where we have awesome animated Brains On episodes. Just search Brains On Universe on YouTube and subscribe.
Oh, and if you have a question, we'd love to help you answer it. Drop us a line by going to brainson.org slash contact. See you next time and the next day and every weekday. Until then, om. Ah, finally at the nose hair salon. I'll just take a booger buzz cut, please.