Previous: The Massive Flood That Triggered an Ice Age (w/ PBS Eons!)
Next: New 8-Letter DNA Rewrites the Genetic Code | SciShow News



View count:104,922
Last sync:2022-11-13 03:45
This week, Dr. Shini Somara goes toe to toe with Hank in a battle of wits about fluid dynamics and life in space.

Hosted by: Michael Aranda

Check out Shini on Crash Course Engineering or Physics:

SciShow has a spinoff podcast! It's called SciShow Tangents. Check it out at
Support SciShow by becoming a patron on Patreon:
Huge thanks go to the following Patreon supporters for helping us keep SciShow free for everyone forever:

Greg, Alex Schuerch, Alex Hackman, Andrew Finley Brenan, Sam Lutfi, D.A. Noe, الخليفي سلطان, Piya Shedden, KatieMarie Magnone, Scott Satovsky Jr, Charles Southerland, Patrick D. Ashmore, charles george, Kevin Bealer, Chris Peters
Looking for SciShow elsewhere on the internet?
Boxfish Cars:

Coffee Spillage:

Projectile Penguin Poop

Life on Mars:

Flies on Titan

Flies in Wine:


 (00:00) to (02:00)


Michael: Hello and welcome to SciShow Quiz Show, the best quiz show on SciShow.  I'm your host, Michael Aranda.  Today's contestants are Hank Green, Missoula's most famous author with the last name 'Green'. 

Hank: Thanks.

M: And battling Hank in this elite competition is Dr. Shini Somara, host of Crash Course Engineering and Physics and engineer extraordinaire.  Welcome, Shini.

Shini: Hi.  

H: How are you feeling?  Are you ready for this?

S: Scared.  

H: Yeah?

S: Yeah.  

H: The good news is that I never know the answers.

S: Oh good, so I'm gonna win.

H: I just--it's all about deducing what's probably wrong and then picking between the other two.  

S: Okay.

H: Yeah.  

S: Thanks for the tip.

M: As a thank you to our amazing supporters on Patreon, we've chosen two of you at random to win some prizes that Hank and Shini are going to compete for.  Hank, you're competing on behalf of Erin Mills.  

H: Hi, Erin.

M: Shini, you're playing on behalf of Evan deFilippo.  

S: Hi Evan deFilippo.  

M: Stefan, show our players what they can go home with today!

Stefan: Alrighty, let me tell you something about what's at stake here today in the Prize Zone.  Erin and Evan, both of you are going to get elegantly autographed cards from today's final round, but the winner will receive the delightful 'I Won SciShow Quiz Show' pin and some secret SciShow swag from, and the person who comes in second place will get a pin commemorating their placement, and that pin says 'I Lost SciShow Quiz Show', but of course, everyone's a winner here today, because we made this video.  Just for you!

M: You both start off with 1,000 points.  If you get a question right, you'll earn some more.  If you get a question wrong, you lose some.  This is largely arbitrary.  Okay, let's dive into our first round, fluid dynamics.  

H: Ohhhh.  What!  Wait, is it like, tongue-in-cheek fluid dynamics?  We'll find out.

S: Actually, I feel pressure.

H: Yeah, that's the thing.

M: Ahhh, is that a pun?

H: When you don't know something you should know that's--oh, is that a pun?  

 (02:00) to (04:00)

Was it a good--was that a good fluid dynamics pun?  I feel pressure now.

S: It was a good one.  I miss that.  It's been a while.  

M: In the mid-1990s, scientists from Mercedes-Benz were looking to nature for inspiration about their next car design.  Their goal was to find a design that was super safe and fuel efficient by basing their vehicle on animals known for their sleekness.

H: On fish.

M: Specifically, a quirky reef creature called the boxfish.  The car that resulted, the Bionic, was really hyped up, but it never made it to market, probably because Mercedes completely misunderstood the benefit this fish gets from its boxy shape.  So the question is, which of the following is actually true about their cubic bodies: they self stabilize so they don't get knocked around by waves, they're incredibly maneuverable, they have exceptionally low drag, the angled edges are hard for predators to grip onto?

S: The last one.

H: Angled edges?  That's the one I was gonna guess.

M: Unfortunately, that is incorrect.

H: See, that's why you gotta go second.  I'm gonna go with it's like, weird for waves to hit them.  Like, they don't get--oh, I got it wrong as well.

M: That is also incorrect.  

S: Was that--which one was that?  The first one?

H: Which one was it?

M: The answer was they're incredibly maneuverable.  

H: Okay.

S: The box?

H: The box.  A maneuverable box.  

Olivia: The answer is B, they're incredibly maneuverable.  Despite that clunky appearance, researchers used to think that this fish's boxiness reduced drag and also stabilized itself.  The idea was that the boxiness would create little vortices of water that righted the fish if it was pushed from any direction, a concept called fortex lift, but as a study in 2015 explained, none of that was true.  Boxfish have 2-5 times the drag of other fish species, and their boxes are actually incredibly unstable.  Basically, their bodies constantly try to roll, the exact opposite of what you would want in car, but it works for the boxfish because it makes them super maneuerable.  Their tiny fins, which act like rudders, give them surprising control over the rolling their bodies want to do.

 (04:00) to (06:00)

So all that instability just makes it easier for them to change course quickly, and that's especially helpful if you're a little reef fish that's constantly having to dart back into the coral.

M: Speaking of stability and fluids, it seems like it's almost impossible to fill a mug of coffee at work, then bring it back to your desk without spiling it.  Thankfully, an engineer decided to tackle this problem with science in 2016.  They found that a mug's shape is perfectly designed to spill when you walk while holding the cup by its handle.  The good news is, there are ways to counteract this phenomenon.   So if you don't want to spill your cup of joe, you should do which of the following: walk faster, tilt the cup 35 degrees--

H: Just pour out your coffee!  That's good.  That will prevent it from spilling.  You pour out some of it and then you walk.  Okay, good.

S: Drink tea.

H: Drink tea.  That's good.

M: --walk backwards, or hold the mug farther away from you?

H: I'm gonna--I love walk backwards.  Just like--it's good.  I'm more smooth now. I'm gonna go with hold your arm out, 'cause at least that way it doesn't get on you.  

M: That is not correct.

S: Yes!  The first one.

M: You're also incorrect.

H: Wow, we're so bad at this.  

M: Hank, you were really close there.  It was walk backwards.

H: Was it walk backwards?

M: Yeah.  

S: Why?

H: Nugget.

O: The answer is C, walk backwards.  Usually, people hold their coffee mugs by the handle and walk with them held out in front of their bodies, but that's pretty much the worst way you could do it, because it turns out your wrists' natural wobbliness is probably what puts the coffee over the top.  Coffee in a standard mug has the resonance frequency between 3 and 4 Hertz.  When it's jiggled at that frequency, slower sloshes build to create bigger and bigger waves.  Your natural body movement alone isn't enough to create that frequency, but your hand doesn't move in tune with the rest of your body.  

 (06:00) to (08:00)

It ends up going forward and backward at a faster rate, probably because your wrist isn't super rigid, and that means the front-to-back sloshes do resonate, quickly building until the coffee flies out of your mug, but if you could strap your coffee to your waist, that would likely solve things, but a simpler method is walking backwards.  For some reason, maybe because you're less coordinated in reverse, walking backwards dampens the oscillation frequency below that 3 Hz threshold.  Of course, walking backwards might increase your risk of collision in a more general sense, which would lead to more spilled coffee, so the researcher proposed a few other ways to dampen the oscillations.  You can hold the cup from above like a claw, add a layer of foam, or use a differently shaped container.  Whatever works, right?

H: Well, this is going badly.

S: Yeah.

H: For every--for both of us.

M: Okay.

H: Let's get some right.

M: As birds who live on the ground, pooping poses a bit of a problem for adelie penguins.  Fecal matter in the nest smells and could damage their feathers and they can't just waddle away to poop far from the nest, because that would mean exposing their eggs to the extreme Antarctic cold and leaving their turf unguarded.

H: This is a great point.

S: Is this still fluid dynamics?

H: Yeah, we'll see how the fluid gets--

M: Asking the important questions.

H: The fluid is going to get dynamic in just a second.

M: Luckily, the penguins have a solution.  They can projectile poop.  

S: Whoa, okay.

H: See, dynamic.

M: But which of the following is not true about their defecation?  They generate some 60 kilopascals of pressure to expel their feces?

H: Who hasn't been there?

M: They can shoot their poop up to half a meter away?

H: Okay.

M: They focus their fecal squirts in one direction or the color of their poop depends on their diet?

H: I'm gonna say they don't focus their poop in one direction.  They surround their nest with a circle of poop.  Yes!

O: The answer is C.

 (08:00) to (10:00)

They focus their squirts in one direction.  Adelie penguin nests are often decorated by a ring of poop streaks which range in color from white to pink, depending on the animal's diet.  These streaks have apparently fascinated some scientists who may have spent a little too long on cold and isolated Antarctica, and we've actually explained the basics of them in another SciShow episode, but it just so happens that with a few key variables, like the height and angle from which the poop emerges, you can calculate how much pressure a penguin has to produce to projectile poop and that's exactly what real scientists did for a 2003 paper in the journal Polar Biology.  They estimated that the penguins produce between 10 and 60 kilopascals of pressure when pooping, which allows them to shoot their liquidy fecal matter a surprising 50 centimeters from their nest, but learning all that raised more questions than it answered.  It's not clear how or why the streaks radiate so evenly from the nest, for example.  You'd think they'd aim with the wind, but wind direction isn't that random.  The researchers even wondered if they choose the spacing deliberately, because it certainly is the more aesthetic choice.  

M: And with that, we're ready for our second round, life in space.  This round is all about aliens, kind of.  It's actually about types of life that could potentially survive elsewhere in the universe.  

H: Okay.

M: If we ever find life on another world, it will probably be something super tough like bacteria.  In fact, NASA scientists have already done experiments investigating how resilient bacteria can be to otherworldly conditions.  In 2015, they took an especially hardy strain and launched it into the stratosphere about 38 kilometers above the Earth's surface for around eight hours.  Up there, conditions are a lot like the surface of Mars, so this was essentially a test of whether they could make it on the red planet and amazingly, some of the spores did survive.  Roughly how many made it?  Was it less than 1 in 1000, 1 in 10,000, 1 in 100,000, or 1 in 1,000,000?

 (10:00) to (12:00)

H: Oh.  So it was--all of those are fairly uncommon.  Yeah, you go ahead.  (?~10:07)

S: Million?

M: Unfortunately, that is incorrect.

H: This is pure--I have to answer this question.  One in 10,000?  

M: That is also incorrect.

H: Alright, what is it?

M: It was 1 in 100,000.  Duh.

H: Of course.

M: Of course.  

O: It's C, less than 1 in 100,000.  The rod-shaped bacteria that scientists tested are one of the most UV-resistant species they've ever found, but even they couldn't make it 8 hours in the stratosphere, and that was actually kind of a relief.  See, earlier, various bacteria had managed to survive the harsh chemicals used to sterilize spacecraft parts, and as a result, it's thought that some 56,000 spores made it to Mars on the Curiosity Rover, which isn't great if you're trying not to contaminate a planet.  At the time, it was unclear if this was a big problem, since we didn't know if these bacteria could survive an intense, DNA-disrupting radiation they'd experience there, but based on this 2015 experiment and others, it looks like they generally can't.  Phew.  Of course, the limited bacteria that did survive also had unique genetic mutations which suggests bacteria could evolve and adapt to Mars, and the researchers also found that the shaded undersides of the bacteria-covered plates they launched into the stratosphere fared pretty well.  So any bacteria that managed to get into shady crevices or inside Curiosity could have survived and that means there may indeed by life on Mars.  Let's just hope it stays on the Rover.

H: That was not set up for us to do well.  That question.

S: Okay.  Or the entire quiz.  

M: Bacteria aren't the only species that might survive on other planets.  At least one researcher has also experimented with breeding fruit flies to live on other worlds.

H: What?

M: Specifically, Saturn's largest moon, Titan.  

H: What?

M: In 2011, a bioartist created special chambers to mimic the conditions on Titan and started breeding colonies of flies to adapt to them.

 (12:00) to (14:00)

He hoped to create a whole lineage that could survive there, which he planned to call (?~12:11).  

H: Good name.

M: Obviously, living on Titan would require all kinds of adaptations, but which one of the following is not a condition the bioartist had to worry about: methane rain, lower gravity, orange light, or decreased atmospheric pressure?

H: I have no idea.

S: Orange light?

M: That is incorrect.

H: Oh man.  Decreased atmospheric pressure?

M: That is correct.

S: Wow

H: Weird.

S: You got it right.  

O: In some ways, Titan seems like the perfect place to live, if you have to leave Earth, at least.  Its surface looks more Earth-like than pretty much anywhere else in our solar system because it has lots of liquid flowing about, creating rivers, lakes, and other familiar features.  It's just that the fluid is natural gas, not water, but still, it looks a lot like Earth and there's likely some water flowing underground, which could help sustain the Earth-borne flies.  But there were a few other challenges that flies on Titan would have to face.  For one, it only has 14% of the gravity that Earth's surface does and it's always very cold.  Its atmosphere is also made mostly of nitrogen and methane, which isn't great for breathing, but if nothing else, that atmosphere is much thicker than Earth's.  That means the air pressure at the surface is much greater, so the flies would actually have to withstand higher pressure than they do here.

M: And that brings us to the end of round two.  Let's see where our contestants stand heading into our final round.  Shini, you've got 600 points.  Hank, you're at 1100.  

H: Uh-huh.

M: Uh-huh.  Well, it all comes down to this.  Make your bets based on your knowledge of spoilers.  

H: Ooh, spoilers.

M: While you guys place your bets, we're gonna go to commercial break.

 (14:00) to (16:00)

Welcome back, probably.  You guys ready?

H&S: Yeah.

M: Let's say you're sitting on a porch having a nice glass of iced tea when a fly lands in your drink.  Some people would fish it out and continue on, but many say that the entire glass is ruined.  Well, in 2018, science sided with the latter.  It turns out that a single fruit fly landed in a drink can spoil the entire glass.

H: Oh no!

M: But only if it's a female one.

S: What?

H: (?~14:27)

S: Why do you always blame us?

M: Is it because the flies carry their eggs externally, the flies release a gross-smelling pheremone, the flies are coated in a super sweet tasting compound, or bacteria on the flies can cause severe intestinal disease?

S: Do we write this?

H: Yeah, you write down what you think is the answer.

S: The last one.  The--oh, I shouldn't tell you.  

M: Spoilers!  

H: Well, I'm gonna guess a different one.

M: Reveal your answers.  I think you're both incorrect.

H: Oh my God, of course we are!

S: Yes!

O: It's B.  The flies release a gross-smelling pheromone.  The life of a common fruit fly is dominated by smells.  They use them to track down their meals and to find mates, so it's not surprising that female flies produce specific scents that male flies find irresistible.  What might be a bit more surprising, though, is how well we can smell those odors.  Researchers have found that people can tell male and female fruit flies apart by scent alone.  When researchers put just a single female fly in a glass of wine, sommeliers could sniff it out and said the wine smelled off, and when the researchers used the purified compound, the participants' noses could detect a mere nanogram of the stuff, roughly 10 times less than the amount on a single fly, but males don't produce the stuff and the participants couldn't reliably detect them.  

 (16:00) to (17:00)

M: That makes Hank Green our winner with 1100 points to Shini's 0 points.  Congratulations.  

H: Oh man.  What was it?

M: The answer was gross-smelling hormone, er, pheromone.

H: I can't smell a fly!  

M: Science said it in 2018, Hank.  

H: Somebody put a fly in my cup.  I'll drink it every time.

S: Someone was doing a lot of research.

H: Yeah.  

S: Can you imagine, it's like, no, that (?~16:32)

H: This is, yeah, what is the research that is being done?  Just drinking?  Sounds good to me.

S: No, that was good.  That was good, too. 

M: Well, thanks for watching this episode of SciShow Quiz Show.  If you want to see more of Shini, you can check out Crash Course Engineering or Crash Course Physics at