A (3:40)

Quick question, smarty pants. When do you think the invention of the submarine happened? In the 20s? The 30s, or the 40s? If you said the 20s, you're right, kind of, because you're probably thinking of the 1920s, but it's really the 1620s.

B (3:59)

That's right. Trusty inventors were testing primitive versions of submarines for over 400 years.

A (4:07)

Another quick question, Smarties. Which was the first war where a submarine was used? Was it the American Revolutionary war, the American Civil War, or World War I? Believe it or not, it was the American Revolutionary War. In 1776, a man named David Bushnell built a small, round wooden submarine that could only hold one person, and he called it the Turtle. It was designed to secretly place explosives on the outside of British ships, causing them to sink. Naturally, General George Washington loved this idea. Unfortunately, the ship carrying the Turtle out to sea sank to the bottom of the ocean before the Turtle could ever be used. Whoops. But they did give submarines another try. In the Civil War, a Confederate army sub called the Hunley was made out of bulletproof iron and could hold up to eight soldiers. It was powered by a hand crank. However, the Hunley didn't fare much better. While its crew did manage to sink one Union ship with a torpedo, they wound up sinking themselves in the process. And the Hunley joined the Turtle at the bottom of the se. Okay, so submarines clearly got off to a less than stellar start. But let's back up, Professor. How are things supposed to work? For starters, how do submarines make themselves sink intentionally?

B (5:47)

The secret is something called buoyancy. The more buoyant something is, the more likely it is to float. A submarine is able to control its level of buoyancy by using its ballast tanks.

A (6:02)

I see. And ballast tanks are.

B (6:05)

A ballast tank is a compartment in a boat, ship, or floating device that's designed to hold water. When you want a submarine to float on the surface, you fill its ballast tanks with air. That makes the sub less dense than the water around it, so it floats. But when you want it to go up underwater, you need to push the air out of the tanks and fill them with water instead. That makes the submarine more dense than the surrounding water, so it sinks. The submersible we're in right now works the same way, but uses heavy weights instead of water.

A (6:51)

Ah, just like me at the gym. Okay, so let's say a submarine does go underwater. How long can it stay under before it needs to surface again? What do you think, smarty pants? Is it A, one day, B, three months, or C, 25 years?

B (7:15)

Well, that's kind of a tricky question, Trusty. You see, America's submarines used to run on diesel power. And diesel engines need oxygen, so those subs have to surface nearly every day to get air. But in 1954, they launched the first nuclear powered sub called the Nautilus. And today, all of our submarines are nuclear powered. Nuclear engines don't need oxygen. So theoretically, those subs could stay underwater for 25 years.

A (7:57)

Whoa. Ah. So do most submarines stay down for that long?

B (8:02)

No, because submarines also run on a different kind of fuel. It's a special combination of Twinkies, hot dogs, chicken, chips, a fruit or vegetable veg, maybe even.

A (8:13)

Oh, you mean food for the crew.

B (8:16)

Exactly. Submarines only have so much room to store food. Usually enough to last about 90 days or three months.

A (8:25)

Aha. So, smarty pants, if your answer to my previous question was three months, congrats. But technically, the other two answers were also kind of right. Professor, did you just.

B (8:38)

No, that wasn't me.

C (8:40)

Sorry. That was me. Trusty. I thought you might get hungry, so I brought you some meat cake. I sampled a little. Okay, a lot, but it's delicious.

A (8:50)

Thanks. I'll have some later. But now it smells pretty bad in here. I'd open a window, but I don't think that's a good idea.

B (9:00)

No, that's a very bad idea.

A (9:03)

Why do we have just one tiny window? Care to guess, smarty pants? Is it because, A, there's nothing to see, B, a window might break, or C, windows are annoying to clean?

B (9:17)

The answer, of course, is B, they might break. As we go deeper and deeper under the ocean's surface, our submersible, just like a submarine, is under more and more pressure. In fact, when we get to the bottom, the pressure on the outside of our craft will be 1,000 times more than we started. If something went wrong, all that pressure could instantly crush our submersible. Like an aluminium can, or do you say aluminum? An aluminum can.

A (9:52)

I wish you hadn't told me that.

B (9:54)

It's okay. You're safe. Underwater vehicles are made from super strong materials like titanium and steel.

A (10:02)

Not much glass, but meatcake lady brought up an interesting point I did. Spending three months in a confined space with a hundred other crew members could get pretty stinky.

C (10:14)

Oh, I get it.

A (10:16)

Not to mention, wouldn't they run out of oxygen? Where do submarine crews get fresh air to breathe?

B (10:21)

Well, one thing people on a submarine have plenty of access to is water. As in seawater. And water is a combination of hydrogen.

A (10:36)

And oxygen, which is why we call water H2O.

B (10:41)

Exactly. The H stands for hydrogen and the O for oxygen. So the trick is figuring out how to get the oxygen out of the water so the crew on the submarine can breathe it.

C (10:52)

That I don't know.

A (10:53)

Me neither. Luckily, there's a professor on board.

B (10:58)

They're actually able to separate the hydrogen and oxygen molecules by passing electrical current through purified seawater. This process is called electrolysis.

C (11:09)

Oh, sounds complicated. Unlike my recipe for meat cake, which is just meat and cake.

B (11:16)

But wait, there's more. Submarines also have devices on board called CO2 scrubbers. These scrubbers use chemicals to remove carbon dioxide the crew members exhale. By adding oxygen and removing carbon dioxide, you now have a breathable underwater environment.

A (11:43)

Wow, what a marvel of science. Okay, so we've talked about the food and air on submarines, but what about drinking water? Everyone knows you can't drink ocean water because of all the salt.

B (11:54)

You're right. But luckily we know how to take the salt out of it.

A (11:59)

What do you think, smarty pants? Do they remove the salt by freezing the salt water, boiling the salt water, or politely asking the salt to scram? The answer is boiling.

B (12:14)

Or what we call desalination. On board every submarine is a distillation plant where seawater is heated until it becomes steam that removes all the salt. That steam is then cooled, which turns it back into water. Only now it's fresh water you can drink. They can churn out 40,000 gallons of fresh water a day on a submarine.

A (12:44)

Wow. Submarines definitely have come a long way since the turtle.

B (12:49)

Speaking of a long way, we're now around 34,000ft deep.

A (12:55)

Speaking of, we're in a special submersible submarine which allows us to go this deep. But a regular nuclear submarine can't go this deep, right?

B (13:04)

Oh, no, not even close if it tried.

A (13:09)

So, smarty pants, how deep can a submarine go? Normally, I'd do a Multiple choice answer. But for this, there's actually multiple answers. Right, Professor?

B (13:18)

Yes, with most nuclear subs, you don't want to go any further than 200 meters or 600ft down. But subs have been known to go 300 meters or over 900ft down, and some have gone even further down. But it's certainly not advisable.

A (13:37)

Um, what's that?

B (13:38)

Our sonar.

A (13:40)

Oh, good. Um, what's sonar?

B (13:43)

Sonar, spelled S O N A R stands for sound navigation and ranging.

A (13:50)

Oh, is that how a submarine knows where it's going?

B (13:53)

It can definitely help, but that's not the main reason submarines use sonar.

A (13:58)

Yikes. Sounds like the sonar is trying to tell us something. We'll find out what it is and what sonar does right after this quick break.

D (14:09)

October 10th is World Mental Health Day, and this year, we're saying thank you to therapists. Behind every person who takes a step forward on their mental health journey is a therapist who showed up, asked the right question, or created a moment that changed everything. BetterHelp therapists have supported more than 5 million people worldwide. That's millions of stories and millions of small wins that add up to big change. Personally, I'll never forget the first time in therapy when my therapist really helped me see a challenge from a new angle. It was like a light bulb went on. That's why I'm so grateful for the therapists who help people every day. BetterHelp makes it easier to begin your own journey by matching you with a license Therapist online. With 12 plus years of experience and thousands of therapists, chances are they'll find the right match for you this World Mental Health Day. Celebrate the therapists making a difference. Our listeners get 10% off the first month@betterhelp.com WhoSmarted that's BetterHelp. H E L P.com WhoSmarted.

A (15:15)

Now back to whosmarted. Professor, what's going on? What is the sonar telling us? Smarty pants? Do you know?

B (15:23)

Well, sonar tells us two important things. Number one, whether we're going to run into something. And two, if you're in a combat situation, how far away your target is.

A (15:38)

What is it saying now?

B (15:40)

It's nothing to worry about. Just some sea cucumbers ahead.

A (15:44)

Phew. So how does sonar work?

B (15:47)

You hear those pings? That's our sonar emitting a pulse of sound into the water and listening for it to echo back. Because we know how fast sound travels through water, we can use the amount of time it takes to rebound to calculate how far away an object is.

A (16:12)

Smarty pants Any idea how fast sound travels through water? Is it 1,000 miles per hour, 2,000 miles per hour, or 3,000 miles per hour?

B (16:22)

The answer is roughly 3,000 miles per hour, or about 1 mile per second.

A (16:30)

Aha. So sound travels through water at one mile per second, and it takes five seconds to hear the echo. Then that object is. Did you say about five miles away, Smarty pants. Great job. If you got that.

B (16:44)

Some animals, like bats, whales, and dolphins use a version of animal sonar called echolocation.

A (16:52)

Um, professor, more cucumbers?

B (16:55)

No, we're getting close to something near the ocean floor. Ah, I see it. It's a hydrothermal vent.

A (17:03)

Is that good?

B (17:04)

No. Hydrothermal vents on the openings of underwater volcanoes. The superheated water coming out is 700 degrees. It could melt the window of our submersible, and then we'd be.

A (17:19)

Oh, boy. What do we do?

B (17:22)

Surface. Quick, release the weights. The natural buoyancy of the submersible's foam body will lift us back to the surface. It'll take a while, but we're safe.

A (17:36)

Phew. That was close. Well, thank you, Professor. We sure learned a lot of cool stuff about submarines.

B (17:42)

My pleasure, Trusty.

A (17:45)

Oh, no, not again.

C (17:47)

Sorry. Volcanoes give me gas.

A (17:52)

A special shout out to CC In New Hampshire. You told us who Smarted is your.

D (17:57)

Go to podcast that we help you learn so much. Well, Cici, that makes you a top.

A (18:02)

Tier smarty pants in our book. Thanks for listening. This episode Submarines was written by Steve Submariner Melcher and voiced by Emma Wilson, Adam Das Boot Davis and Jerry Colbert. Technical direction and sound design by Josh Hunt for Red October Khan who Sparted is recorded and mixed at the Relic Room Studios. Our associate producer is Max Crimson Tide Kamasky. The theme song is by Brian Upscope Suarez with lyrics written and performed by Adam Tex Davis. Who Smarted was created and produced by Adam Tex Davis and Jerry Colbert. This has been an Atomic Entertainment production.