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Mark Sanchez
Lemonade.
Maya
Brains on Universe. You're listening to Brains on. Where we're serious about being curious.
Molly Bloom
Some things are simple and complex at the same time.
Maya
Like getting dressed in the morning.
Molly Bloom
Yeah, you just need to put on clothes. Simple.
Maya
But wait, do I want to look bright and peppy or cool and dark? Is it shorts weather or jeans weather? What will my friends be wearing? Do these socks go good with these shoes? Is my favorite hoodie clean enough to re wear?
Molly Bloom
Yikes. See? Complicated.
Maya
Another example is the light bulb.
Molly Bloom
You flick a switch and bada bing, you got light. Simple.
Maya
But what's going on inside the bulb to make the light turns out? That part is complicated.
Molly Bloom
Don't worry, we're gonna explain it right after this. We've gotten a lot of feedback on our new show, Brains on Universe presents Pubert Podcast. People have written us things like, as a parent of a seven year old, thank you. And I find all of this super uncomfortable to talk about. So a podcast through my headphones only I can hear is helpful. The full series is in its own feed. We are so glad it's helpful. That was the goal and something we couldn't have done without our Smarty Pass pals. When you join SmartyPass and you should, you help us serve families with things like the puberty podcast, which is full of scientific explanations and helpful advice and also lesson plans, special events and. And of course, our shows, which are fact checked and help fuel a love of learning. So join today@smartypasts.org Every member lets us do more to help kids understand their world and themselves. Do your part@smartypasts.org thanks.
Mark (Mailroom)
Brains on.
Molly Bloom
You're listening to Brains on, part of the Brainz on Universe. I'm Molly Bloom and here in the studio with me is Maya from Durham, North Carolina. Hi, Maya.
Maya
Hi, Molly.
Molly Bloom
Today we're answering a question that you sent in.
Maya
Yeah, I wanted to know how a light bulb works.
Molly Bloom
So, Maya, how did you come up with that question?
Maya
Actually, my sister helped me come up with the question. We were in the car and we passed a streetlight and she was like, how does this work? And I asked the question too. And my mom was like, oh, this is a good one for Brains On.
Molly Bloom
Do you have a favorite light or lamp in your house?
Maya
Well, yeah, I think in our bathroom there's a connection with three light bulbs and it's facing up. It's really cool. Colors you can change. You can turn it darker or brighter.
Molly Bloom
Oh, it's dim or bright. Oh, very cool. Do you have a nightlight?
Maya
Yes, I do. But I also have this jellyfish lamp, too.
Molly Bloom
Oh, cool. That sounds amazing. Well, the light bulb is a fantastic thing to explore because there's a lot of cool science behind it.
Maya
But before we tackle that, we need to start with something even more important.
Molly Bloom
Light itself. Where exactly does light come from?
Maya
Light is basically a kind of energy.
Molly Bloom
There are lots of kinds of energy, but light is a special one because we can see it.
Maya
But hold up, Molly. There are all types of light we can't see, right?
Molly Bloom
Like infrared light or ultraviolet light.
Maya
Yeah, those.
Molly Bloom
True. Yeah, we can't see either of those kinds of light. The type of light we can see, we call visible light, because it's visible.
Maya
So visible.
Molly Bloom
All the light we see from fires to screens to the sun, comes from atoms.
Maya
Whoa.
Mark Sanchez
Atoms.
Maya
Those teeny, tiny, smaller than a germ, building blocks of everything.
Molly Bloom
Yeah, those atoms are like the Legos that all the stuff in the universe is made of. And when an atom gets hit with extra energy, part of that atom gets super excited.
Maya
That part that gets all jazzed up is called an electron.
Molly Bloom
So imagine a little electron floating around its atom, minding its own business when
Maya
it gets hit by a jolt of energy. Wowza. What was that? Oh, boy, howdy. I feel hyped up. Let's party for a little while.
Molly Bloom
That jolt of energy makes the electron super excited,
Maya
but soon enough, the electron calms down. Well, that was fun. But let's simmer down now. Let it all out.
Molly Bloom
When the electron in that atom goes back to normal, it lets go of that energy. It sort of shoots it out.
Maya
And for some atoms, that energy is shot out as a beam of light.
Molly Bloom
So to recap, light comes from atoms. When energy hits an atom, the electrons in that atom get all excited.
Maya
Then when those electrons calm down, they shoot that energy back out.
Molly Bloom
Sometimes the energy leaves the atoms as a beam of light. So this idea that you take one form of energy, zap atoms with it, and. And the atoms turn it into light. That's the big idea behind how light bulbs work. Now let's light up your ears with a challenge, shall we? It's time for the mystery sound. All right, Maya, turn up your ears. Here it is. Do you want to hear it again?
Maya
Yes.
Molly Bloom
Okay, here it is. All right. What guess do you have?
Maya
It sounds like a little shaking, maybe. This is hard.
Molly Bloom
It is a tough one. Yeah. What could possibly be shaking?
Maya
Maybe, like, Legos or like, maybe Magnatiles.
Molly Bloom
Could be Magna tiles, could be Legos. Well, we're gonna hear it again. Get another chance to guess and hear the answer at the end of the show.
Maya
So keep listening.
Molly Bloom
Everything at Brainzonn is powered by you.
Maya
Yeah. Your ideas, art, mystery, sounds and questions.
Molly Bloom
So send us stuff. You can do that@brainzon.org contact we read everything that comes through there and if
Maya
we pick your question you might get to co host an episode. That's how I got here.
Molly Bloom
So again send questions, ideas, reactions or whatever to our team@brainson.org contact can't wait
Maya
to hear from ya.
Molly Bloom
Today's episode is sponsored by Shopify. When we went independent here at Brainzon, there was a lot to figure out and it was pretty overwhelming. And when you're starting something new, it just feels like the to do list keeps growing, growing and growing and growing. But that's why finding the right tool that not only helps you out but simplifies everything can be a game changer for us. One of those tools is Shopify. Shopify is the commerce platform behind millions of businesses around the world and 10% of all e commerce in the US Shopify is your commerce expert with world class expertise in everything from managing inventory to international shipping to processing returns and beyond. And if you get stuck, Shopify is always around to share advice with their award winning 24. 7 customer support. Start your business today with the industry's best business partner, Shopify and start hearing. Sign up for your $1 per month trial at shopify.combrainson go to shopify.combrainson that's shopify.combrainson.
Sandin Totten
Do you love light? Like really love light? Like love light so much you took all your savings and bought hundreds of lamps, sconces, chandeliers and light fixtures, then moved them all into an abandoned shoe store that's probably haunted and opened your own light themed store that sells nothing but lights. Well then you must be me because that's exactly what I did. Hi. I'm sorry. Sandin and I just opened Sandin's Bright Idea, a store for light lovers. We've got night lights, bright lights, white lights, fright lights, kite lights. Those are lights on kites. Afraid of height lights. They hate being on kites. We sell lamps. Clamps for lamps, lamps for champs. Those are lamps shaped like trophies. Damp lamps. They're wet. Actually, don't touch those. We've got chandeliers that bling. Lanterns that swing a bulb on a string. Give me a ring, hear me, I'll sing. I love light. So come on down to Sandin's Bright Idea, located at the abandoned shoe store that's probably haunted near some Roads and a tree maybe. I don't know, I forget. But you know where I'm talking about, right? Come on, it's light. You know you need it. Sandin's bright idea will light up your life and house.
Molly Bloom
Welcome back to our look at light bulbs. I'm Molly.
Maya
And I'm Maya.
Molly Bloom
And aside from lighting our homes, light bulbs are also used in cartoons and comics to show when someone has a good idea.
Maya
Yeah. A cartoon character thinks and thinks, then, aha. A light bulb appears above their head. An idea.
Molly Bloom
Sometimes they also shout I've got it. Or eureka.
Maya
We wanted to know what you would shout out when you have a light bulb moment.
Molly Bloom
And boy, do you have some bright ideas.
Kids/Listeners
Here's what I think you should shout
Maya
when you have an idea. Brightness. Like your light bulb is brighting up.
Kids/Listeners
I would shout brain nuggies. And the thing I would say is shrug bomba. I will say ding dong. And when I have a light bulb moment, I would probably shout, my brains are on for a light bulb moment. I'd say
Maya
if I had a light
Kids/Listeners
bulb moment, I would shout anuka. And that means I got an idea.
Molly Bloom
That was Teddy, Zsaza, Elsie, Mana, William, Amy and Evan. Maya, what would you say?
Maya
Um, I would probably say banana. Like a peeling banana.
Molly Bloom
Like, oh, oh.
Maya
Like I'm opening a banana.
Kids/Listeners
Oh, yeah.
Molly Bloom
It's like there's the idea. It's the banana. Yeah, I like that. I like that a lot. Alright, back to the bulbs themselves. How exactly do they make light?
Maya
We know you can get visible light by taking one form of energy and zapping an atom with it.
Molly Bloom
That atom will then release that energy, sometimes as light. So how does that work with light bulbs? Let's find out.
Maya
Let's start with the old fashioned light bulbs.
Mark Sanchez
Yeah.
Molly Bloom
If you've seen a rounded bulb with a little squiggly line in the middle, that's what we're talking about.
Maya
Oh, like the light bulb on the Brain's on logo.
Molly Bloom
Exactly. That squiggly line is actually a coil of thin metal wire. It's called a filament. And the type of bulb that uses a filament is called an incandescent bulb.
Maya
Incandescent. Incandescent.
Molly Bloom
Incandescent. That metal filament is the key to the light. It works like this. When you flick the light switch in
Maya
your house, it sends electricity through some wires.
Molly Bloom
In an instant, the electricity reaches the bulb and it is sent through that metal wire.
Maya
As it flows through the wire, the electricity bumps and smashes into the atoms that make up the wire. Excuse me. Oops, sorry. Coming through.
Mark Sanchez
Ouch.
Sandin Totten
Ooh.
Maya
Pardon me.
Molly Bloom
With every bump, the electricity transfers energy to the atoms, specifically to the electrons in those atoms. Now, remember before how we said when certain atoms get hit with energy, the electrons absorb it and then release it as light?
Maya
Well, the metal in the filament is made up of those kinds of atoms.
Molly Bloom
The filament is made of a metal called tungsten.
Maya
When you run electricity through tungsten, it heats up. The metal gets hotter and hotter.
Molly Bloom
Then the electrons in the atoms absorb energy from that heat and get excited. And when they calm down, then they release that energy as light. So basically, the electricity heats up the metal until it's so hot it glows and gives off light. Kind of like how the metal coils on an electric stove light up when they get hot. Or how if you left a fire poker in the fire too long, it might glow too.
Mark Sanchez
Brain spun
Molly Bloom
a couple more things about these incandescent bulbs. Why are they made of glass? Why not just have a wire that glows?
Maya
Well, when some things get very bright and hot, they burn up tungsten.
Molly Bloom
The metal in light bulbs is usually like that.
Maya
Make it hot and burns away.
Mark Sanchez
Poof.
Molly Bloom
No more light. But it needs oxygen to burn out like that. If you keep it away from oxygen, it won't burn.
Maya
That's why these little metal wires are in glass bulbs. There's no oxygen in there.
Molly Bloom
Instead, the glass bulbs are filled with a gas that won't burn them out. Usually it's a gas called argon.
Maya
Also, notice how we said the metal wire thingy gets very hot?
Molly Bloom
That's because the atoms in tungsten don't just make light, they make heat too. The heat and the light are both coming from these excited atoms.
Maya
Yeah, you might have noticed that these bulbs can get pretty toasty after they've been left on for a while.
Molly Bloom
But we only want the light. It's wasting energy to make all that heat we don't need.
Maya
Which is why humans have invented other kinds of light bulbs that don't make so much heat.
Molly Bloom
We'll explain those in just a bit. But first, let's check the mailbag.
Mark (Mailroom)
Hey, Mark here in the Brainzon mail room. Has anyone seen my can opener? Here it is. It's in my hand. It's always the first place you should look, you know? Anyway, time to open some cans of mail from you. Oh, yeah. We got some new ideas for empty rooms in our headquarters. Like this one from Miles.
Kids/Listeners
An idea for a room in the new Brainsland headquarters is a Big chocolate
Maya
fountain with animals running around such as
Kids/Listeners
dogs, cats, butterflies, horses and cows.
Mark (Mailroom)
Amazing. Messy, but amazing. Ooh, and check out this idea from Theo.
Kids/Listeners
I want to make a room for the new headquarters. Dance on. Anti gravity room. And it's really hot with popcorn, so you can see like the popcorn pop. Because I've always wanted to see that
Mark (Mailroom)
popcorn popping in zero G. Oh yeah, I definitely want to see that. And lastly, here's an idea from Avery. He thinks we should have a room full of tigers.
Kids/Listeners
Fun fact. Tiger cub depend on entirely on their parents for food until they are 18 months old and ready to hunt prey. Another fun fact is tigers fur helps of camouflage because when the sun shines off of their fur, it looks green to other animals. Finally, tigers are endangered, which means there are only around 5,500 left in the wild. And that is why I think you should have a room full of tigers.
Mark (Mailroom)
Thanks so much for all these ideas. If you want to add a room to the BrainZN headquarters, just send us an idea by going to brainson.org contact that's brainson.org contact thanks and see you in the mailbag.
Molly Bloom
Brains on is supported by listeners, which means it's supported by you. Join Smartypass to help out and get ad free versions of this and all of our other shows. Visit smartypass.org thank you. Thank you.
Sandin Totten
Hey, it's Sandin from the one and only Sandin's Bright Idea, the light store for light lovers. Come visit us at the abandoned shoe store that's probably haunted. We've got desktop lamps, track lighting, spotlights.
Mark Sanchez
Hey, how'd you get in here?
Sandin Totten
Oh, wow, a ghost. This abandoned shoe store is haunted.
Mark Sanchez
I'm not a ghost. I work here. And this shoe store isn't abandoned. We were just closed.
Sandin Totten
Oh, that explains why there's still so many shoes.
Mark Sanchez
Where did all these lights come from? You need to get them out of here.
Sandin Totten
Breaking news. We're having a flash sale. All lights 50% off. Come get them now.
Mark Sanchez
Seriously, you gotta leave before my manager gets here. Ouch. I stubbed my toe on this floor lamp.
Sandin Totten
New sale. Buy one light, get the rest free. Just come grab what you can before we get thrown out.
Mark Sanchez
Shoo, shoo, shoo.
Molly Bloom
Get out of here.
Mark Sanchez
Good day. Be gone. I said good day.
Sandin Totten
Actually, it's an all you can carry sale. Give me five bucks and you can supermarket sweep this place. Hurry, hurry.
Mark Sanchez
I'm gonna call security.
Sandin Totten
Wait. You know what this shoe store really needs? 15 giant chandeliers.
Mark Sanchez
Get out.
Sandin Totten
Okay, bye.
Molly Bloom
We're Back. And we just learned that incandescent light bulbs work by sending electricity through a metal wire.
Maya
That wire absorbs that energy and releases it back out as heat and light.
Molly Bloom
But as we said, that's pretty wasteful. It wastes a lot of energy making heat when all we really want it to do is make light.
Maya
That's where LED lights come in.
Molly Bloom
LED stands for light emitting diodes.
Maya
Light emitting diodes.
Molly Bloom
LEDs. These are pretty different from incandescent bulbs. Instead of having a filament, LEDs have a special material called a semiconductor.
Maya
A semiconductor is not a conductor of a train who only works part time.
Mark (Mailroom)
Who's driving this train?
Maya
Not me. I'm off duty for the rest of the ride. I'm just a semiconductor.
Molly Bloom
Yeah, not that. A semiconductor is a material that electricity can flow through, but electricity doesn't flow through it as easily as it does through metal, like aluminum.
Maya
But it's not a material that electricity can't move through at all.
Molly Bloom
Like rubber, it's somewhere in between. It conducts or carries electricity. Sorta. Okay. It's semi good at it.
Maya
The semiconductors in LEDs are made of two layers.
Molly Bloom
One layer has extra electrons, and one
Maya
layer doesn't have enough electrons.
Molly Bloom
Remember, electrons are the parts of atoms that get all excited when they get hit with energy.
Mark Sanchez
Wow.
Maya
And they can release light when they calm down, let it all out.
Molly Bloom
So you have one layer with too
Maya
many electrons and one layer that has room for more electrons.
Molly Bloom
Seems like they should work together and share electrons, right?
Maya
Yep. And that's what they do.
Molly Bloom
When you send electricity through these two materials, it moves the electrons from the part that has extra electrons to the part that wants more. Oh, boy.
Maya
I love sharing. There's enough of us electrons for everyone. But here's the thing. For the electrons to join the new material, the part that wants more electrons, they have to release some energy. Oh, this seems like a good spot to rest. But I have too much juice for this place. I'll just let out some energy so I can settle down over here.
Molly Bloom
And like we said before, when electrons calm down and give off energy, it can shoot out as light, which is exactly what happens here. The electrons move from one material to the other, and as they do that, they drop their energy and shoot off light.
Maya
And as long as the electricity keeps flowing through the semiconductor, electrons keep moving from one material to the other, releasing a steady flow of electronic light along the way. So LEDs are basically little machines that move electrons from one place to another.
Molly Bloom
But as they move, they're forced to lose energy, which makes light. And by changing the materials in the semiconductor, we can change how much energy the electrons lose. Losing different amounts makes for different colors,
Maya
and that's how we make different color LED lights.
Molly Bloom
Most new bulbs these days are LED bulbs because they make very little heat and a lot of light, which means
Maya
they can use less energy to make light.
Molly Bloom
Plus, LEDs can last much longer than older incandescent bulbs. It's a win win. Now you know how light bulbs work.
Maya
You can say, aha. I get it now.
Molly Bloom
Speaking of aha, let's hear more of your ideas for what to shout when you have a light bulb. Mom,
Maya
here is what I think we should say when we get a lightbulb moment. Kick the Coke. I've got an idea.
Kids/Listeners
If I had to make a word to say when I had an idea, it would be ooblee success Bean. My new word whenever something good happens is horsetastic, because I ride horses. And whenever my horse does something really good or I do something really nicely, that's what I would say.
Maya
The phrase I think we should say is melting popsicles. And what I think we should say when we have a light bulb moment is Liberty Giblet.
Kids/Listeners
See you soon, Brainzon.
Molly Bloom
Thanks to Robin, Marla, Aurora, Ruby, Moon and Indigo, Grace, Phaedra and Elliot.
Maya
You all rock.
Molly Bloom
When someone asks you how a light bulb works, you can give them the simple answer or the compliment.
Maya
The simple answer is that when you turn on a light, electricity is sent through a bulb where it is turned into light.
Molly Bloom
The complicated answer is that when you turn on a light, that electricity zaps
Maya
a bunch of atoms, and those atoms absorb the energy with their electrons.
Molly Bloom
The electrons then shoot that energy back out. In incandescent bulbs, the energy comes out as heat and visible light.
Maya
In LED lights, electrons move from one material to the other, and as they move, they have to lose energy, and
Molly Bloom
that energy is released as light for us to see. That's it for this episode of Brains On. This episode was produced by me, Molly Bloom, Marc Sanchez, and Sandon Totten. It was sound designed by Mark Sanchez, who also wrote our theme music. We had engineering help from Jenny Lawson. Special thanks to Ken Taborski at Code of the north for all of their website help. Also, special special thanks to Lena Neil, Margaret Teich and Suchin Shukla. Maya, are you ready for that mystery sound again?
Maya
Yeah.
Molly Bloom
Okay, here it is.
Mark Sanchez
Hmm.
Molly Bloom
What do you think?
Maya
I'm gonna go with Legos.
Molly Bloom
Okay. I like that. Shaking Legos up. Maybe you're looking for a piece.
Kids/Listeners
You Need.
Molly Bloom
Excellent guess. Okay, here is the answer.
Maya
Hi, I'm Lena from Durham, North Carolina. And that was the sound of me shaking ice in a plastic cup. And I dedicate this to my sister, and she's just the best. Aww.
Molly Bloom
That was from your sister and she fooled you?
Maya
Yes, darn it, Lena. And Lena really likes ice. So.
Molly Bloom
So you should have known she was shaking ice. That's a good one. Nice job, Lena.
Maya
Good job, Lena.
Molly Bloom
Now it's time for the brains honor roll. These are the incredible kids who keep the show going with their questions, ideas, mystery, sounds, drawings and high fives. Frances from new york city, vanir from vaughan, ontario. Garrett from writing, massachusetts. Izzy from republic, missouri. Eloise from houston, texas. Eleanor from grand rapids, michigan. Zara from lakewood, colorado. Connor from cherry hill, new jersey. Udai from grand prairie, alberta. Midori and penny from san francisco. Barney from bound brook, nj. Owenfrom jim thorpe, pa. Ellic from henley on thames, england. Vivian and belle from coralville, iowa. Chloe, atlas and oakley from bennington, n.h. clara, june and annie from richmond, virginia. Win from cincinnati, luca from tampa, florida. Logan from cincinnati. Halawi from washington, d.c. lavon from washington, d.c. rita from mississauga, ontario. Aida from montreal amala from belgium, india. Mitra from windsor, california freya from brainerd, minnesota karuna from providence, rhode island. Alex from brooklyn, new york xander from richfield, washington levi and owen from santa clara, california. Ben from crownsville, maryland alice from champaign, illinois quinton from st. Paul, minnesota cassandra from st. Paul, minnesota emma june from edmonton, alberta lucy from baltimore quinn from san pablo, california evelyn from campbell river, british columbia, columbia hudson from charlotte, north carolina huy lee from sydney, australia ethan from flower mound, texas rosie from guelph, ontario. Leo from maitland, australia. Tova from eprot, israel. Lynden from codale, alberta justin from garland, texas hunter from mccrom, ireland cora from anchorage, alaska luca from newtown, pennsylvania lucy and charlie from lakewood, ohio. Faron from birmingham, united kingdom. Reese from chico, california xander from clarksville, tennessee hunter from walpole, massachusetts nora and isaac from amerinik, new york. Leo from from southwater, united kingdom. Lincoln and kelty from gooding, idaho. Ciro from oakland, california catherine from philadelphia and annika, from abington, pennsylvan. We'll be back next week with another visit from the Hoax Hunters.
Maya
Thanks for listening.
Episode: How do lightbulbs work?
Host: Molly Bloom
Kid Co-host: Maya from Durham, North Carolina
Date: June 23, 2026
This fun and enlightening episode explores the science behind lightbulbs—how something so seemingly simple (flip a switch and—bada bing!—you've got light) can actually be quite complex on the inside. Host Molly Bloom and kid co-host Maya tackle the question: How do lightbulbs work? Along the way, they discuss atoms, electrons, energy, classic incandescent bulbs, the rise of LEDs, and more—explaining everything in clear, kid-friendly language with infectious curiosity and playful banter.
| Time | Segment | |--------------|----------------------------------------------| | 03:09–05:08 | What is light? Atoms & electrons explained | | 05:10 | Mystery sound challenge #1 | | 09:47–11:09 | Lightbulbs as a symbol for ideas | | 11:43–14:39 | How incandescent bulbs work | | 19:12–22:10 | What are LEDs and how do they work? | | 23:34–24:12 | Simple vs. complex answer summaries | | 24:43–25:09 | Mystery sound answer & sibling twist |
| Bulb Type | How It Works | Efficiency / Quirks | |-----------------|------------------------------------------------------------------|-----------------------------------------------| | Incandescent | Electricity heats tungsten filament, exciting electrons | Lots of heat; glass filled with argon | | LED | Electricity moves electrons across a semiconductor (two layers) | Very little heat; energy efficient; lasts long |
This episode of Brains On! illuminates the hidden science inside every lightbulb—from atoms and electrons to temperature and color. Incandescent bulbs use heat and glowing metal, while LEDs rely on advanced materials and efficient electron shuffling. The show wraps up with a “you can explain this!” boost for listeners—empowering young scientists to share both the simple and complex answers about how lightbulbs work.
Memorable Listener Participation:
Favorite new “lightbulb moment” exclamations include:
Sibling Moment:
Maya is outsmarted by her sister Lena in the mystery sound segment, creating a funny and sweet ending.
“Now you know how light bulbs work. You can say, aha, I get it now.” — Maya (22:32)