How does soap work?

Summary

Podcast Summary: Brains On! — “How does soap work?”

Episode Date: April 28, 2026
Host: Molly Bloom
Kid Co-Hosts: Hope & Heaven (sisters from Raleigh, NC)

---

Episode Overview

This episode dives into the surprisingly dramatic science behind how soap cleans our hands and kills germs. Host Molly Bloom, along with her kid co-hosts, Hope and Heaven, zoom in (literally!) on the microscopic world of soap molecules, dirt, and germs, explaining soap’s power with fun analogies, songs, and playful side characters (including viruses hoping to survive your handwashing routine). Plus, the show celebrates two key historical figures in hand hygiene and explores how soap was first invented.

---

Key Discussion Points & Insights

1. Soap vs. Germs: The Microscopic Battle

• Scene Setting (03:09–05:10):
  Molly, Hope, and Heaven set the stage by discussing handwashing habits and soap preferences (bar vs. liquid, fruity vs. flowery scents).

• Zooming In On Soap (05:19–10:05):
  Using a make-believe “zoom ray,” listeners see how soap works at the microscopic level.

• How Soap Works:

  • Soap molecules look like lollipops:
    • The round “head” loves water (hydrophilic).
    • The long “tail” hates water (hydrophobic) and seeks out dirt and oils.
  • These tails burrow into grime and germ membranes, especially viruses, pulling them apart and surrounding dirt.
  • When you rinse, the hydrophilic ends follow the water, pulling germs and dirt away from your hands, down the drain.

Memorable Explanation:

“Those water hating soap tails are also burying themselves in the viruses on my hands.” — Molly (08:35)

• Practical Tip:
  Twenty seconds of scrubbing allows soap to do its job (sing the birthday song twice!).

2. The Science Song (10:21)

A fun, short song sums up soap’s “cool trick”:

“Soap, it has a cool trick / To gunk it will stick / Stabbing viruses and exploding them / Cleaning you up real quick.”

3. The History of Soap (17:24–19:34)

• Origins:

  • Soap has existed for at least 5,000 years.
  • Early soap may have been a happy accident: animal fat and ashes from a fire mixing with water created slippery cleaning sludge.
  • Soap is made by combining fatty acids (animal or plant) with a base (like ash or lye) in a process called saponification.

• Fun Fact:

  “For hundreds of years, washing your hands with soap was not very common. Soap was mostly used for washing fabrics or in religious ceremonies.” — Molly (19:21)

4. Soap, Germs & Hygiene: Pioneers Who Changed the Game (25:05–28:37)

Ignaz Semmelweis (mid-1800s Hungary)

• Noticed doctors were getting patients sick after working with cadavers.
• Had doctors wash hands before treating healthy patients; patient illness dropped.
• Was ignored by peers because nobody knew germs existed at the time.

Florence Nightingale (Crimean War, Istanbul)

• A statistician and nurse who cleaned up hospital conditions and pushed for hand and face washing.
• Her efforts reduced deaths from infection among soldiers, even before “germs” were proven real.

Memorable Quote:

“It goes to show that sometimes smart people can come up with great solutions, even when they don’t fully understand the problem.” — Molly (27:57)

5. Fun Character Segments

Viruses Take the Mic ("Going Viral with Kara and Gilly") — (14:06–17:03, 21:31–24:44)

• Comical viruses "complain" about how soap ruins their plans:
  • “We get on your hands, we’re ready to get the party started. But then you go and wash your hands with soap…it stops the whole party before it even starts.” — Gilly (16:12)
• Salmonello (Salmonella bacteria) brags he’s “immune” to soap because his cell wall is different – only to be rinsed away:
  • “The soap molecules didn’t break me apart, I win!…Oh no…Now I’m being carried off by the water.” — Salmonello (23:28–24:03)

---

Notable Quotes & Memorable Moments

• On Soap Molecules:

  "Like a dog and a cat sharing the same body.” — Hope, describing soap’s two-sided structure (07:37)

• On the importance of handwashing:

  “Don’t rush it. Give soap around 20 seconds to do its thing. That’s like singing the birthday song twice.” — Molly (10:16–10:19)

• On ancient discoveries:

  “Maybe it rained…and that sludge was washed down in a nearby river. When people went to wash clothes in that river...a very early version of soap was born.” — Molly (18:11–18:22)

• On science pioneers:

  “The hands are key. Clean them and you will save more patients.” — as Dr. Semmelweis (26:20)

---

Timestamps for Important Segments

• Handwashing Habits & Soap Preferences: 03:11–04:44
• How Soap Works in Detail: 05:19–10:05
• Soap Science Song: 10:21–10:54
• History of Soap & Saponification: 17:24–19:34
• Semmelweis & Nightingale Stories: 25:05–28:37
• Virus Comedy Segment: 14:06–17:03, 21:31–24:44

---

Useful Takeaways

• Soap doesn’t just “wash” germs away — it actively destroys certain germs (especially viruses) by breaking them apart.
• Both sides of a soap molecule (water-loving and water-fearing) work together to grab dirt and germs and flush them away.
• Handwashing for 20 seconds is key for thorough cleaning.
• Soap has a long history but only became a hygiene staple for handwashing in the late 1800s, thanks to people like Ignaz Semmelweis and Florence Nightingale.
• Most bacteria are physically removed by soap rather than killed, but viruses with certain membranes are burst open by soap.

---

Episode in a Nutshell

This lively, kid-friendly episode makes the science of soap come alive, showing why handwashing is so powerful and how tiny molecules win the war against dirt and germs. It combines playful sound effects, informative explanations, musical mnemonics, and quirky characters to help listeners visualize (and remember!) the chemical magic happening every time they scrub up.

---

For Further Listening

Stay tuned for next week’s episode about…the Earth spinning!

Transcript

[A]

Lemonada. Today's episode is sponsored by Great Wolf Lodge. At Great Wolf Lodge, there's adventure for the whole family. You and your pack can splash away in the indoor water park where it's always 84 degrees. There's a massive wave pool, a lazy river, and tons of water slides for your pack to enjoy together. And the fun doesn't stop there. Get ready to explore and play at Adventure packed attractions, from Magiquest, a live action game that takes place throughout the lodge, to the Northern Lights Arcade. There's also a bunch of great dining options and complimentary daily events like nightly dance parties all under one roof. And the best part, with 22 lodges across the country, you're always only a short drive away from adventure. So bring your pack together at a lodge near you. Book your stay [e-mail] and strengthen the pack.

[B]

Brains On Universe. You're listening to Brainzon, where we're serious about being curious.

[A]

When you wash your hands, there's a battle going on.

[C]

One between the soap and the dirt and germs on your skin.

[B]

It's a nasty fight with brutal attacks and no mercy.

[A]

The soap wins and the dirt and germs lose. Big time.

[C]

But how?

[B]

Yeah, what exactly does soap do to Crystal's filthy foes?

[A]

Turns out soap has a special design that makes it the perfect thing to kill germs and clean dirt. To see how it works, you have to zoom in super close.

[B]

Which is exactly what we're going to do.

[C]

Keep listening.

[D]

Hi, I'm Mark Sanchez, here to talk about an important issue. Do you have questionitis? It's a common condition that afflicts curious kids and sometimes adults, too. Symptoms include wondering what octopuses dream of, contemplating how Jello wiggles, asking why penguins can't fly, and questioning the existence of time itself. If you or somebody you love is dealing with questionitis, there is help. By joining Smartypass, you can get access to hundreds of episodes of Brains on that answer your questions, all without ad breaks. You also get forever ago smashboom Best and Moment of AD Free. And if that's not cool enough, you get invited to online hangs with me, Molly and Sandin. And you support the work we do helping other people with Questionitis because you have a gazillion questions and we have a gazillion answers. Join [e-mail] smartypass thanks.

[A]

Brains On. You're listening to Brains on, part of the Brainzn Universe. I'm Molly Bloom and my co hosts today are sisters Hope and Heaven. From Raleigh, North Carolina. Hi, guys.

[E]

Hi.

[A]

Today we're scrubbing and bubbling and tackling this listener question.

[B]

How does soap work?

[A]

So, Hope in heaven. Are you both pretty good at remembering to wash your hands?

[B]

Yeah.

[C]

Yes.

[A]

Do you prefer. Let's start with you, Hope. Do you prefer bar soap or liquid soap?

[C]

I prefer liquid soap because it's less slippery than bar soap. Cause usually when you're in the shower or bath, when you're holding the bar soap, the water's on your hands and sometimes it just slips in the water. Mm.

[A]

How about you, Heaven?

[B]

Liquid soap is, I just find more helpful because if it does fall off your hand, it just falls on the ground and it's in a bottle so it won't get dirty. So. And also if the bar soap falls down, it will get dirty.

[A]

Are you guys shower people or bath people?

[B]

Shower people.

[A]

And how about fruity smelling soap or flowery smelling soap? How about start with Heaven?

[B]

I prefer fruit smells.

[C]

I prefer flower smells because it makes me feel like I'm in like a garden of flowers while I'm taking a shower or a bath.

[A]

Oh, yes, very nice. I mean, you can't go wrong either way. You know, I kind of like a cucumber smelling soap, which is a little bit odd, but I really find it refreshing. Okay, so I have a question. I'm gonna start with Heaven. Who takes longer in the morning to get ready in the bathroom? Would you say you or Hope?

[B]

Hope.

[C]

Yeah, it's definitely me. I take like the longest in the bathroom in the morning.

[B]

Of course she does.

[A]

So Heaven, do you have any tips for how to go quicker in the morning?

[B]

Yeah, of course. In the morning she gets ready slower because she's usually sleeping when I'm awake. And also with her shower, she takes like long. And sometimes I hear her singing in the shower, but she takes like forever.

[A]

Yeah. Braaaaaaaaaa. Well, let's get to it. The science of soap.

[C]

We know it's important when we wash

[B]

our hands, but what exactly does it do besides, you know, smelling good and

[C]

making those fun foamy bubbles?

[A]

One way to find out. Zoom in real close and see what's going on. Luckily, we have a zoom ray for that.

[C]

Ooh, the zoom ray.

[B]

I've always wanted to see it in action.

[A]

Well, here we go. This device lets us look super close at something so we can see stuff on a microscopic level. Ready to zoom Hope in, Heaven?

[B]

Super ready.

[C]

Zoom us in, Molly.

[A]

Okay, I'm gonna wash my hands. Heaven, you aim the ray at the sink and Hope, please push that red button right there.

[C]

Got it.

[A]

Whoa.

[B]

We're so close, we can see stuff that's normally too small to see.

[C]

Super cool.

[A]

I know. Now, as you can see, there's some dirt on my hands. The water is washing over it. And some of it's coming off, but not all of it.

[B]

Yeah, some of it looks stuck on there. And what are those spiky looking balls?

[A]

Oh, those are viruses. Maybe some cold germs must have picked them up somewhere. You can also see some bacteria and even tiny fungi on my hands.

[C]

Gross. No offense, Molly.

[A]

No, I get it. Same. We are covered in tiny micro things. Most are harmless, but it's good to wash up and get rid of the bad ones. Those are the ones that can make us sick. So let's vanquish those viruses. Watch as I add some soap into the mix.

[D]

Whoa.

[C]

Look at those tiny lollipops.

[A]

Those are soap molecules. Molecules are tiny pieces of something. Up super close. Tiny pieces of soap do look like lollipops. You can see each molecule of soap has a round ball on one end and a long tail on the other. Now, the thing about soap is that those two ends are very different. One side, the side that looks like a ball. It loves being in water. Like, look at that soap molecule there.

[B]

Oh, a bath. Yay. Let's go for a swim.

[A]

But the other side, the long thin tail, it hates water. It wants to get as far away from wet things as possible.

[F]

Water. Yuck.

[A]

No.

[F]

Get it away from me. Get it away.

[C]

Yikes. Seems tough for those two sides to be paired together.

[B]

Yeah, they're opposites. Like a dog and a cat sharing the same body.

[A]

Exactly. And this is what makes soap such a great cleaner. Because that long stem that hates water, it's going to look for any way it can to get away from the wetness.

[B]

Splish, splash. So fun in the bath. Am I right, Tail?

[A]

Ah.

[F]

Are you out of your mind? Water is the worst. Get me out of here. Wait, is that some dirt?

[A]

Oh, yay.

[F]

That's not water. Let me bury myself in that. Ah, safe at last.

[B]

Huh?

[C]

The tail end of the soap just buried itself in that grime on your hands. Like sticking a pin in in a pincushion.

[B]

Look, lots of soap molecules are doing the same thing.

[C]

The dirt on your hands is now covered in soap molecules and they're lifting the dirt off your skin.

[A]

Yeah, and look, those water hating soap tails are also burying themselves in the viruses on my hands.

[F]

Oh, this germ looks like a safe place to hide. Let me just wiggle in here. Ah, that's better.

[B]

Whoa. Lots of soap molecules are burying themselves in that.

[E]

They're prying the virus open.

[C]

The soap broke the germ apart. All the viruses on your hands, they're being utterly destroyed.

[B]

Viruses are bursting all over the place. Cool.

[A]

Yeah. Now that I'm done lathering my hands with all this soap, watch me rinse it off. The side of the soap that loves water is going to follow the water as it washes off of me, and it's going to take its tail that's buried in viruses and dirt with it.

[F]

More water.

[A]

Yay.

[B]

Let's surf this wave. Come on, tail. Woo hoo. What a ride. Whee.

[F]

I'm holding onto this germ and I won't let go. I hate water.

[G]

Wow.

[C]

The soap took all that grime and all those dead viruses with it.

[B]

Your hands aren't gross anymore.

[A]

Thank you. Now hit that button there and we'll zoom back out.

[B]

That was action packed.

[G]

Yeah.

[C]

The soap Molly Cools went to town sticking into that dirt and busting up those germs.

[A]

Like I said, soap is powerful stuff. So next time you wash your hands, picture that wild battle between soap and grime. And remember, don't rush it. Yeah.

[C]

Give soap around 20 seconds to do its thing.

[B]

That's like singing the birthday song twice.

[A]

Or singing this soap song we wrote twice. Happy Washington.

[D]

Soap, it has a cool trick to gunk. It will stick, stabbing viruses and exploding them, cleaning you up real quick. Soap, it has a cool trick to gunk. It will stick, stabbing viruses and exploding them, cleaning you up real quick.

[A]

Coming up, we're going to learn when humans started making soap. But first, let's take a break for the

[B]

mystery sound.

[A]

Okay, are you guys ready to guess the mystery sound?

[B]

Yes.

[A]

Awesome. Here it is.

[C]

I know what it is.

[B]

Yeah, I have a guess too.

[H]

Yeah.

[A]

Okay, let's hear. Who wants to guess first?

[C]

Yeah, you can go.

[B]

Heaven. Okay, so I have heard this song before in my own home. So I believe it's a wash. It's in a washroom and it's a washer. Like when you put clothes in and then pour the thing and then start it.

[C]

Yeah, it sounds like a washing machine. Like, yeah, a washing machine. Like you pressing the buttons and then letting it turn closed in the inside.

[A]

Feels like you two heard that and you were like, I know this sound.

[B]

Yeah.

[A]

Awesome. Okay, well, we're gonna hear it again at the end of the show, get another chance to guess and hear the answer.

[C]

So stay tuned.

[A]

Right now, we're working on an episode all about light bulbs. Light bulbs are often used to symbolize getting an idea. When you get a good idea, you might imagine a light bulb turning on over your head.

[B]

Ding.

[A]

Or maybe when you get a good idea, you shout eureka. Well, we want to hear from you. We would love for you to invent a new word to say for when you get a good idea. So, hope in heaven, what's your new word or phrase to announce a good idea?

[C]

Mine is, I think, like, happy or like, happy face.

[A]

Yeah, maybe like, instead of a light bulb symbol, we'll use a happy face symbol.

[B]

Yeah, I think I'd say brains on, probably.

[A]

Oh, I'm honored. I'm so honored. That's amazing. Well, listeners, we want to hear from you two. Send your answers to [e-mail] contact. We'll play some of them on an upcoming episode. Today's episode is sponsored by Great Wolf Lodge. At Great Wolf Lodge, there's adventure for the whole family. You and your pack can splash away in the indoor water park where it's always 84 degrees. There's a massive wave pool, a lazy river, and tons of water slides for your pack to enjoy together. And the fun doesn't stop there. Get ready to explore and play at adventure packed attractions, from Magiquest, a live action game that takes place throughout the lodge, to the Northern Lights arcade. Also, a bunch of great dining options and complimentary daily events like nightly dance parties, all under one roof. And the best part, with 22 lodges across the country, you're always only a short drive away from adventure. So bring your pack together at a lodge near you. Book your stay [e-mail] and strengthen the pack.

[G]

Hey, friends.

[H]

It's your two favorite viruses.

[G]

Meet Gilly and meet Kara.

[H]

And this is going viral with Kara and Gilly.

[G]

Oh, yeah.

[A]

Oh, yeah.

[H]

Hey, viralinos. Long time no see.

[G]

We missed you. We hope you've been staying infecty, making people sick, living your best life, riding on a sneeze.

[H]

For sure. For sure. So we just wanted to interrupt this episode of Brains on real quick to talk about something.

[E]

Soap.

[B]

I hate it.

[G]

Oh, the worst un.

[H]

Fun soap is highly effective at killing viruses.

[A]

Yeah.

[G]

For those who don't know, viruses like us are just microscopic little things that want to get in your body and make you super sick. Fun, right?

[A]

I think so.

[H]

And we love hanging out on, like,

[G]

doorknobs, railings, phones, pencils your friend lent you during math.

[H]

Anywhere we can get to your hands, because we don't actually move by ourselves. You have to touch something to pick us up. Or maybe if we're lucky, we'll be sneezed onto you.

[G]

The achoo choo choo. Like traveling on a sneeze. Get it?

[E]

Maybe.

[H]

Keep workshopping that one.

[G]

But however it happens, once we're on your hands, there's a good chance you'll put us in your mouth or your nose.

[H]

Maybe when you're eating. Maybe when you're picking your nose, we're

[G]

the bostrals of your nostrils.

[A]

Yeah, sure.

[H]

And once we get in, the virus party starts.

[G]

Hey, don't party like a virus party, because the viruses don't stop. Like, literally. We start multiplying, taking over the place. We have a blast. And you'll get sticky, sick real quick. Quickie quick.

[H]

But so many of you humans really know how to ruin a party.

[G]

Party poopers.

[H]

We get on your hands, we're ready to get the party started. But then you go and wash your hands with soap.

[G]

It stops the whole party before it even starts. We get washed away, down the drain. And you stay healthy. Bummer town, bummer city, bummer nation.

[H]

So remember, if you love being sick

[G]

with viruses, and honestly, who doesn't?

[H]

Then say nope to soap.

[E]

Thanks.

[A]

We are back. I'm Molly.

[C]

I'm Hope.

[B]

And I'm Heaven.

[A]

And we're exploring the sudsy world of soap.

[B]

We learned soap molecules have one side

[C]

that loves water and one side that really doesn't.

[B]

And that side sticks to the dirt and germs to get away from water. That helps get that grime off your

[C]

skin so water can rinse it all away.

[A]

Humans have been making soap for a long time, at least 5,000 years.

[C]

Historians found recipes for it from cultures in ancient Mesopotamia, Egypt, Greece, and Rome.

[B]

No one knows how it was invented, but one pretty good guess is that it was a happy accident.

[A]

Maybe something like this. Long ago, a group of people had a cookout.

[B]

They ate some meat roasted over a fire.

[C]

Fat from the meat dripped into the flames and mixed with the burnt wood.

[A]

The fat mixing with ashes created a chemical reaction, creating a slippery sludge.

[B]

Maybe it rained the next day and

[C]

that sludge was washed down in a nearby river.

[A]

When the people went to wash clothes in that river or clean up their bodies, they noticed that sludge from the fire made the water super good at taking off dirt and grime, and a

[C]

very early version of soap was born.

[A]

That's one theory of how soap was discovered. But probably lots of cultures figured this out in lots of ways over many years because, thankfully, soap is fairly easy

[C]

to make the ingredients are pretty common.

[A]

It's made by mixing fatty acids with a certain kind of substance called a base.

[B]

In the example above, the fatty acid came from the fat in the cooked meat.

[C]

But you can use fatty acids from plants, too, like avocados or coconuts.

[A]

And the base, in our example, came from the burnt ashes of the wood.

[B]

More modern soap makers often use something called lye, which is made from ash.

[A]

Once you combine the fatty acids and the base, they make a reaction called

[B]

saponification, which makes, you guessed it, soap.

[C]

Like magic, but actually, it's chemistry.

[A]

Over many, many years, humans got better at making soaps. But get this. For hundreds of years, washing your hands with soap was not very common.

[B]

Soap was mostly used for washing fabrics

[C]

or in religious ceremonies.

[A]

Coming up, we'll tell you about two people who helped change that. Stick around. But first, let's check the mailbag.

[D]

Hey, friends, it's me, Mark. Checking the mail. Checking the mail. Ooh, it looks like we got a note from two people who recently listened to the smashboom Best debate. Soy sauce versus maple syrup. In that one, Team Soy sauce talks about a food hack where you can mix soy sauce with vanilla ice cream.

[A]

Check it out.

[D]

And if you put some in softened

[A]

vanilla ice cream, then refreeze it, it'll

[D]

make a butterscotch flavor. It's one of those viral food hacks. Well, these two listeners tried it, and here's what they thought.

[C]

I'm Baird.

[B]

I'm 10. I'm Craig.

[G]

I'm 8.

[B]

And we live here in Anchorage, Alaska. The vanilla ice cream with soy sauce in it with soy sauce in it is actually pretty good butterscotch. It's delicious.

[D]

Ooh, very interesting. Who knew a debate show like smashboom Best would have such a great dessert tip? More like smashboom Digest. Am I right? Thanks for sending us your food review, Barrett and Craig. And if you tried something inspired by an episode, let us know. Send it to [e-mail] contact.

[E]

Thanks.

[D]

See you later.

[A]

Brains on exists because of you. If you've been inspired, awed, or just had fun listening, help keep the show going. Join SmartyPass. You get all our stuff ad free and a bunch of other cool things. [e-mail] Thanks.

[G]

What's up, Viralinos? Us again, Cara and Gilly. Two viruses with a microphone and a dream.

[H]

A dream of infecting you so your nose fills with boogies.

[A]

Ah, boogies.

[G]

Little green gobs of joy.

[H]

But sadly, soap ruins our plans. Like, all the time.

[G]

All the time.

[H]

Lucky for us, today we have a guest who says he can beat soap.

[G]

He's a germfluencer, popular in the grimosphere.

[H]

Let's welcome Salmonello.

[G]

Hey, Sal.

[E]

What up, Kara and Gillette?

[G]

So tell us, Sal. You're a germ, right?

[E]

Yep. I'm a bacteria, not a virus like you two. I'm a single celled organism. And my thing is, I like to make people poop a lot. Like, if I get inside a human, I'm gonna make them sick, and I'm gonna make them poop a ton.

[H]

Right, and so you say you aren't afraid of soap?

[E]

No way. I'm not afraid of anything. I mean, look how jacked I am.

[G]

Are you jacked? Can germs even be jacked? You just look like a regular bacteria.

[E]

Look, bacteria like me aren't like you viruses. We don't get pried apart and exploded by soap because our cell walls are different from how you viruses are made up. Soap can't hurt me, bro. Watch this.

[G]

What are you. Yeah. Wait.

[A]

Whoa.

[H]

What's going on?

[E]

I'm covering myself in soap.

[A]

Ew.

[D]

Why?

[E]

To prove how tough I am.

[G]

Okay, but I don't think you should.

[E]

See, the soap molecules didn't break me apart. I win. I am the best.

[H]

Yeah, but you're still covered in soap. Dude, that's not a good idea.

[E]

Now watch me rinse it off.

[A]

Wee hoo.

[G]

Uh, you might not want to do that.

[E]

Oh, no. The soap has me surrounded, and it's making me float in the water. No. Dang. I'm being carried off by the water. Now. I severely overestimated my ability to beat soap. Wow.

[H]

Who could have seen this coming?

[A]

Only us a little bit.

[E]

Okay, I may have let my many insecurities manifest as an outsized need to look super tough. And now I'm being washed down the drain because of it. I should have talked about my feelings instead.

[G]

Well, we tried to help him.

[H]

Viruses and bacteria, no match for soap.

[G]

That reminds me of the time I got stuck talking to E. Coli hanging out on that kitchen faucet. He truly wouldn't stop talking about poop.

[H]

But we can. And we will. Until next time, stay infecty and don't get sanitized.

[A]

Brains. Brains.

[D]

Brains.

[A]

We are back on our soap box,

[B]

talking about soap stuff that cleans like a dream.

[A]

But get this. For centuries, people didn't use soap to get germs off hands.

[C]

Which sounds weird, but there's a good reason.

[A]

For centuries, people didn't know germs existed. They knew people Got sick. But they weren't really sure why. We didn't have microscopes powerful enough to see things as small as germs.

[B]

But eventually that changed.

[C]

Cut to the country of hungary in the mid-1800s.

[B]

Still, before we knew about germs, there

[A]

was a doctor named Ignaz Semmelweis.

[D]

Ack.

[I]

My patients keep getting sick. What could be the reason?

[A]

He noticed something at his hospital, doctors would spend a lot of time inspecting dead cadavers. It was part of their work. Then they'd go straight from that to treating patients.

[C]

Those patients got sick pretty often.

[B]

So Ignaz wondered, could the doctors be

[I]

picking up something by touching the dead? And then they transferred to otherwise healthy patients? Could that be making people sick?

[A]

It was a theory. So to test it, he tried something weird and new.

[C]

He asked the doctors to clean their hands before seeing healthy patients.

[B]

And guess what? It totally worked.

[C]

Way fewer patients got sick.

[I]

Bravo. The hands are the key. Clean them and you will save more patients.

[A]

Even though he had really strong evidence that washing hands helped save lives, he couldn't really explain why this worked so well.

[B]

He just knew that it did.

[C]

So most doctors ignored him. They kept not washing their hands.

[A]

Jump a few years forward and over to a city then called Constantinople. Today it's called Istanbul, in the country of Turkey. Back then, England had a hospital there to treat soldiers who got sick during an ongoing.

[B]

And working at that hospital was a woman named Florence Nightingale.

[A]

She was a statistician, which means she was really good at using numbers and patterns to understand how the world works.

[C]

But at this hospital, she was also helping treat patients.

[A]

And Florence noticed that a lot of soldiers died from illness, not wounds from the war. And she had a hunch that the filthy and crowded hospitals might be to blame.

[C]

She didn't know about germs either, but she thought keeping things clean could make a difference.

[B]

So she made a bunch of changes, like making sure the patients got fresh air.

[C]

And she had nurses regularly wash their faces and hands.

[A]

And once again, this saved a lot of lives. Florence Nightingale became a hero in England, and her methods soon spread to many other hospitals. Not too long after this, the idea that tiny things called germs were making people sick caught on.

[B]

And suddenly washing hands made a lot more sense.

[A]

But it goes to show that sometimes smart people can come up with great solutions, even when they don't fully understand the problem.

[C]

So next time you scrub your hands, think of pioneers like Ignaz and Florence.

[A]

Soap molecules have one end that loves being in water and one end that doesn't.

[C]

The side that avoids water will attach to dirt and germs and help lift them off your hands.

[B]

That makes it easier for the water to rinse all that grime away.

[A]

Humans have been making soap for thousands

[B]

of years, but it wasn't until the mid-1800s that we started washing our hands to stay healthy.

[C]

That's it for this episode of Brains On.

[A]

This episode was produced by me, Molly Bloom, Marc Sanchez, and Sandra Totten. It was sound designed by Mark Sanchez, who also wrote our theme music. We had engineering help from Matt Sanders. Special thanks to Joy and Terry, Cesar, Hezekiah, Harmony, Haven and Hart, Avery Aubrey and Anthony and Kent Daborski at Code of the north for all of his website help. Okay, Hope in Heaven. Are you ready to hear the mystery sound again?

[C]

Yes.

[A]

Okay, here it is.

[C]

Okay, my guess was I had two guesses. The washing machine or a microwave. But I'm kind of leaning towards the microwave now after I heard the sound.

[B]

So I like her. I have both the washing machine and the microwave, But I'm kind of leaning to the washing machine because it really sounds like that.

[A]

Okay, I love it. You guys ready to hear the answer?

[B]

Yes.

[A]

Okay, here's the answer.

[B]

Hi, my name's Rosa. I'm from Somerset. And that was the sound of my dad turning on the washing machine.

[A]

Washing machine is correct.

[G]

That's right.

[B]

That's right.

[A]

Yes. Nice. Incredible work. You were both right the first time.

[B]

Yes.

[A]

And then we got distracted by our microwave, which is totally fine because microwaves do kind of sound like that too, so I totally get it.

[C]

Yeah. Like the beeping and then the closing the door.

[A]

Well, great ears, you guys. I'm very impressed.

[C]

Thank you.

[A]

Now it's time for the brains on ear roll. The incredible kids who keep the show going with their questions, ideas, mystery sounds, drawings, and high fives. Elizabeth from calgary, thomas from sao paulo. Leo from lafayette, colorado. Yuritza from la grande, california. Zoe los altos, california. Noah from wellwind, garden city, united kingdom. Jackson from palisade, california. Hannah from danvers, massachusetts. Audrey from seattle, smyya from singapore. Holden from culver city, california. Antonella from waukegan, illinois. Marin from calgary. Mia rose from perth, australia. Tj from boston. Eckham from san francisco. Wren from victoria, british columbia. Noah from seoul. Maya from san diego. Francis from lincoln, nebraska. Kira and luke from marietta, georgia. Clara from edmonton, alberta. Miles from westport, connecticut. Isabel and gia from encino, california. Eleanor from pleasant hill, california. Barrett from winter park, florida. Wade from denver. Judah from munich, germany. Victor from santander, spain. James from nashville. Addison from plainfield, illinois joan from seattle arlo from wellington, new zealand catherine from madison, wisconsin aubrey and noah from grand rapids, michigan flynn from lehigh, utah oliver from santiago de compostela, spain ben from san francisco rhett, cleo and dax from los angeles amelia from denver lucy from saskatoon krish from wellington, new zealand ivy from keiseltown, virginia roan from eagle river, alaska caleb from randolph, new jersey ivy and marcus from st. Louis larry and annie from los angeles ishan from sunnyvale, california ben from chesapeake, virginia eowyn from orangeville, california evie from austin, texas judah from mcdonough, georgia kaimani from london, england odette from el paso, texas coralyn from simsbury, connecticut ezra from portland, maine marley from toronto felix from calgary leonardo from escondido, california edward from ridgefield, connecticut everly from alder grove, british british columbia milo from golden, colorado abby from elm grove, wisconsin asha from torrance, california sebastian from toronto and isaac from gallup, new mexico. We'll be back next week with an episode about the earth spinning.

[C]

Thanks for listening.