Testing If You Can Blow Your Own Sail

Mark Rober
2 Mar 202417:06

Summary

TLDRThe video explores various physics and engineering puzzles, starting with a test of whether a fan blowing on a sail can move a boat. It continues with a journey to the equator to debunk the myth of water draining in opposite directions due to the Coriolis effect. Other phenomena investigated include the appearance of the moon from different hemispheres, the elliptical room in the US Capitol with exceptional acoustics, the effect of air mass on the movement of objects in a car, and the principles behind sailboats and fan-powered boats. The video also discusses the concept of a floating backpack and the intriguing fact that only a small amount of extra rope is needed to raise a rope around any size circle by one foot. The presenter's goal is to not only inform but also to inspire understanding and curiosity about the physics behind everyday phenomena.

Takeaways

  • 🚀 Testing if a fan blowing on a sail can move a boat forward.
  • 🌍 Traveling to the equator to investigate the Coriolis effect and its impact on water drainage and toilet flush directions.
  • πŸŒ™ The moon appears upside down in the Northern and Southern Hemispheres due to the perspective from Earth's poles.
  • πŸ”΄ The focus points of an ellipse have unique properties where a line from one focus to any point on the ellipse will bounce off and hit the other focus.
  • πŸš— The reason why the cake slides forward and balloons move backward in a car when brakes are applied is due to Newton's laws of motion and the behavior of air mass.
  • 🎈 Air molecules have mass and can exert force, demonstrated by the effect of inflating a balloon and its impact on a sign.
  • πŸ›³οΈ Sailboats move by harnessing wind power, and a fan can theoretically move a boat if positioned correctly, similar to a propeller.
  • πŸ›΄ Debunking the viral video of an umbrella and leaf blower setup on a skateboard, showing it's actually the electric skateboard's battery that powers movement.
  • 🌐 The extra length of rope needed to raise a loop around the Earth by one foot is 6.28 feet, regardless of the Earth's size.
  • πŸŽ’ The Hoverglide backpack claims to reduce impact forces by 86%, but its effectiveness is debated and depends on the terrain.
  • πŸŒ€ The Coriolis effect is responsible for the rotation direction of weather patterns like hurricanes and cyclones, but its effect on water drainage in sinks and toilets is negligible.

Q & A

  • What is the purpose of the fan experiment mentioned in the script?

    -The purpose of the fan experiment is to test whether blowing air on a sail can move a boat forward, similar to how wind propels a sailboat.

  • What does the traveler plan to investigate at the equator?

    -The traveler plans to investigate if the demonstration that water drains in opposite directions on either side of the equator is a scam, as well as the claim that toilets flush in opposite directions in different hemispheres.

  • How does the moon's appearance differ between the Northern and Southern Hemispheres?

    -The moon appears upside down when viewed from the Southern Hemisphere compared to the Northern Hemisphere due to the perspective from opposite sides of the Earth.

  • What is the significance of the focus points in an ellipse?

    -The focus points in an ellipse are special because any straight line shot from one focus point will bounce off the ellipse's wall and hit the other focus point, making them important in physics and geometry.

  • How does Newton's first law relate to the cake sliding forward in a car?

    -Newton's first law, also known as the law of inertia, states that an object at rest stays at rest unless acted upon by an external force. The cake slides forward because it tends to stay still, and the car's sudden stop is the external force that moves it.

  • What causes the air to push the balloon backwards when the car brakes?

    -The air has mass and acts as a fluid. When the car brakes, the air inside the car continues moving forward due to inertia, creating a pressure difference that pushes the lighter balloon backwards.

  • Why doesn't the fan attached to the boat move it forward in the experiment?

    -The fan doesn't move the boat forward because the sail is designed to catch wind, not to propel against the denser water like a propeller would. The fan would be more effective if placed underwater like a propeller.

  • What is the Coriolis effect and how does it influence weather patterns?

    -The Coriolis effect is an apparent force that causes moving objects to be deflected to one side due to the Earth's rotation. It causes weather patterns like hurricanes to spin counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

  • Why does the water in the tourist demonstration appear to drain in opposite directions on either side of the equator?

    -The water appears to drain in opposite directions due to subtle twisting motions made by the person pouring the water, which continues the swirl in the direction of the twist, not because of the Coriolis effect as is commonly believed.

  • What is CrunchLabs and how does it relate to the content of the script?

    -CrunchLabs is a subscription service that sends a fun toy with a video explanation of the physics and engineering principles behind it every month. It is related to the script as it aims to provide educational content in an entertaining way, similar to the experiments and demonstrations discussed in the video.

Outlines

00:00

πŸš£β€β™‚οΈ Sailing with a Fan and Equatorial Experiments

The video begins with an experiment to see if a fan blowing on a sail can move a boat forward. The host then travels to the equator to test the popular tourist demonstration that water drains in opposite directions depending on whether you're in the northern or southern hemisphere. The video aims to debunk myths and uncover the truth behind these phenomena, as well as explore other physics and engineering puzzles. The host also introduces the concept of how the moon's appearance differs between hemispheres and why this is the case.

05:04

🎈 The Physics of Balloons and Air Mass

This paragraph delves into the physics behind why a helium balloon moves backwards when the car brakes suddenly. It explains the concept of air having mass and how it behaves like a fluid, affecting the motion of objects. The host uses the example of a balloon's interaction with a sign to demonstrate how adding air (mass) to the balloon changes the outcome of the collision. The discussion then transitions to the behavior of objects in a car when the brakes are applied, and how the air inside the car contributes to the motion of the objects.

10:04

πŸ›³οΈ Boat Propulsion and the Myth of the Electric Skateboard

The host explores the idea of using a fan to power a boat, comparing it to a viral video of someone using a leaf blower on an umbrella to move on a skateboard. Through a series of demonstrations, it is revealed that the fan does indeed move the boat, but the setup is inefficient and not practical. The video also debunks the skateboard myth by showing that the movement is due to an electric skateboard, not the leaf blower or umbrella. The host then discusses the principles of boat propulsion, including the use of sails and propellers.

15:05

πŸŽ’ The Floating Backpack and the Coriolis Effect

The video examines a Kickstarter product, the hoverglide backpack, which claims to reduce impact forces by 80-90%. The host provides a balanced view of the product's potential benefits and drawbacks, concluding that it may be useful on flat terrain but not on rough hiking trails. The discussion then shifts to the Coriolis effect, explaining its impact on weather patterns and its supposed influence on the direction of water drainage. The host debunks the myth that sinks and toilets drain in opposite directions across the hemispheres, attributing the observed effects to other factors.

🌍 Debunking Equatorial Myths and the Power of Learning

The host concludes the video by debunking the tourist demonstration that claims water drains in opposite directions at the equator. Through careful observation and a simple at-home experiment, it is shown that the demonstration is a trick. The host emphasizes the importance of a passion for learning and introduces CrunchLabs, a subscription service that delivers a fun toy with educational content each month, designed to inspire interest in STEM and engineering among children.

Mindmap

Keywords

πŸ’‘Equator

The equator is an imaginary line on the Earth's surface that is equidistant from the North and South Poles. It divides the Earth into the Northern and Southern Hemispheres. In the video, the equator is significant as it is the location where the presenter investigates the Coriolis effect and its supposed influence on the direction of water swirling in sinks, which is a common demonstration for tourists.

πŸ’‘Coriolis Effect

The Coriolis Effect is an apparent force caused by the Earth's rotation that affects the direction of winds and ocean currents. It causes moving objects to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. In the video, the presenter discusses the Coriolis Effect in relation to the myth about water draining in opposite directions at the equator.

πŸ’‘Newton's Laws of Motion

Newton's Laws of Motion are three fundamental principles that describe the relationship between the motion of an object and the forces acting upon it. The first law, the law of inertia, states that an object will remain at rest or in uniform motion unless acted upon by an external force. The second law relates force, mass, and acceleration. The third law states that for every action, there is an equal and opposite reaction. In the video, Newton's Laws are used to explain various phenomena, including the behavior of objects in a car when the brakes are applied and the movement of a fan-powered boat.

πŸ’‘Ellipse

An ellipse is a geometric shape that resembles a flattened circle, with two focal points inside it. It is defined as the set of all points for which the sum of the distances to the two foci is constant. In the video, the presenter uses the properties of an ellipse to explain how sound waves behave in an elliptical room, allowing one to hear whispers from the other focus point due to the reflection of sound waves.

πŸ’‘Air Pressure

Air pressure is the force exerted by air molecules against the walls of a container or any surface in contact with air. It is caused by the weight of the air above and is affected by altitude and temperature. In the video, air pressure is discussed in the context of a balloon's impact on a sign, illustrating that the air inside the balloon has mass and contributes to its momentum.

πŸ’‘Fluid Dynamics

Fluid dynamics is the study of the movement of fluids, including liquids and gases, and the forces that act on them. It encompasses behavior in both static and dynamic situations, such as the flow of air or water around objects. In the video, fluid dynamics principles are applied to explain the movement of air and water in various scenarios, like the effect of a fan on a sail and the behavior of water in a car's acceleration and braking.

πŸ’‘Physics

Physics is the natural science that involves the study of matter, its motion, and the forces and energies that are associated with objects and systems. It seeks to understand how the universe works at the most fundamental level. In the video, physics is the overarching theme, as the presenter investigates various physical phenomena and principles, such as the Coriolis effect, Newton's Laws, and fluid dynamics.

πŸ’‘Engineering

Engineering is the application of scientific principles to design, build, and maintain structures, machines, devices, systems, and processes. It involves problem-solving and innovation to meet specific needs and improve efficiency. In the video, engineering concepts are applied in the demonstrations and explanations, such as the use of a fan to move a boat and the design of an elliptical room for acoustic purposes.

πŸ’‘Phenomena

A phenomenon is an observable event or fact that is notable for its unusual or distinctive characteristics and can be the subject of scientific study. In the video, various phenomena are explored, such as the apparent sideways appearance of the moon at the equator, the direction of water swirling in sinks, and the movement of objects in a car when brakes are applied.

πŸ’‘Demos and Experiments

Demos and experiments are practical procedures or tests conducted to illustrate or test scientific principles, theories, or hypotheses. In the video, several demos and experiments are performed to investigate and explain concepts like the Coriolis effect, the behavior of air and water under different forces, and the acoustic properties of an elliptical room.

πŸ’‘STEM

STEM stands for Science, Technology, Engineering, and Mathematics. It is an interdisciplinary approach to education that combines these four fields to enhance learning and problem-solving skills. In the video, the presenter's passion for STEM is evident as they explore various scientific principles and encourage viewers to develop a similar passion for learning through their YouTube videos and CrunchLabs.

Highlights

Testing if a fan blowing on a sail can move a boat forward.

Journey to the equator to investigate the tourist demo of water draining in opposite directions.

Exploring the phenomenon of the moon appearing upside down in different hemispheres.

Demonstration of the ellipse's focus points and their properties using a laser pointer and wax.

Investigating why balloons move backwards when a car brakes suddenly.

Experiment with a fan attached to a train car to understand the principles of propulsion.

Explaining the ineffectiveness of using a fan to propel a boat without a sail.

Debunking the myth of toilets flushing in opposite directions in different hemispheres.

The Coriolis effect's role in the perceived direction of water drainage at the equator.

Exposing the tourist demo as a scam with a subtle pouring technique.

The real magic of the video: transferring knowledge from the creator's brain to the viewer's.

Introducing CrunchLabs, a monthly subscription service for learning physics and engineering through toys.

CrunchLabs' aim to make learning fun and engaging for children.

The opportunity to win a platinum ticket to build with the CrunchLabs team.

Investing in the passion for learning through CrunchLabs.

The effectiveness of CrunchLabs in sparking a new passion for STEM among children.

The importance of understanding the physics behind everyday phenomena.

The role of air pressure and mass in the movement of objects in a car.

The concept of Newton's first and second laws of motion in everyday scenarios.

Transcripts

play00:00

I'm about to plug in this fan to test whether blowing on this sail

play00:03

will move the boat forward.

play00:04

And then I'm traveling 4000 miles to the equator

play00:07

where I'm actually standing in both the northern and southern hemispheres,

play00:11

because this line here is the equator, and I'm here to investigate

play00:15

whether or not this demo for tourists is a scam.

play00:18

Basically, they pour water in this basin and on the north side of the equator,

play00:22

it seems to swirl and drain counterclockwise,

play00:24

but just a few feet away in the southern hemisphere.

play00:26

The water seems to drain in the exact opposite direction.

play00:29

It's sort of like how you also might have heard

play00:31

toilets flush in opposite directions on different sides of the equator.

play00:34

And we're here to uncover the truth.

play00:36

But I'm not stopping there because today we're going to investigate

play00:39

six other physics and engineering puzzles using simple demonstrations as we go.

play00:44

Because our goal by the end of this video is for you

play00:46

not just to know the right answers, but more importantly

play00:49

for you to understand and why they're the right answers.

play00:51

To kick things off.

play00:52

Speaking of Hemispheres

play00:54

did you know the moon in the sky

play00:55

looks like this in the Northern hemisphere, like in Canada.

play00:58

But it looks like this in the southern hemisphere, like in Australia.

play01:02

It's upside down!

play01:04

And while that is a fun fact, it's even more fun to understand why.

play01:07

And this is why

play01:08

As we all know, the Earth is...

play01:11

a sphere.

play01:12

So if you were Superman standing at the North Pole

play01:14

in the Northern hemisphere, you'd look like this.

play01:17

But if you were

play01:17

Thor standing in the southern hemisphere in Antarctica, you'd look like this.

play01:21

Now, of course, the moon over here orbits around the earth

play01:25

like this, and I'm going to add an arrow to it to help us with orientation.

play01:29

And so to the Superman at the North Pole

play01:30

That arrow would point up, but from the perspective of Thor at the South Pole

play01:35

That arrow would point down from his perspective.

play01:38

And now I know what you're thinking.

play01:39

If all that's true, then which way would the arrow point?

play01:42

If you're Spiderman, standing here at the equator.

play01:45

Well, according to our model here, it should be sideways

play01:48

and sure enough, here in Ecuador, at the equator.

play01:51

I'm happy to report that the moon does, in fact, appear to be sideways

play01:56

For fun fact two of seven.

play01:57

If you just stick

play01:58

two pins into some cardboard like this and then connect them with a string

play02:02

and trace it out, you get my favorite geometric shape...

play02:05

an ellipse!

play02:06

But there's something really special about these two pinholes.

play02:09

They're called the focus points.

play02:10

And any straight line you shoot out in any direction from one of the points

play02:14

will bounce off the wall of the Ellipse and always hit the other focus point.

play02:18

And here's proof because I've got a laser pointer

play02:20

at one focused point, a ball of wax at the other,

play02:23

and a mirrored surface all along the interior wall.

play02:25

And now you can see, no matter which way I point the laser,

play02:28

it always bounces off and lights up the wax.

play02:31

But here's the really cool part.

play02:33

If you build an actual full sized room

play02:35

in the shape of an ellipse and then you stand at one focus point,

play02:37

you can hear even the faintest whisper from anyone

play02:40

standing at the other focus point, even hundreds of feet away,

play02:43

because all the sound waves bounce right back to your ears

play02:47

in fact,

play02:47

this actual ellipse shaped room was built by John Quincy Adams

play02:51

in the US Capitol building.

play02:52

And legend has it, he was a master at anticipating the moves

play02:55

of his opponents, plotting against him on the opposite side of the large hall.

play02:59

And now that you know the physics involved,

play03:00

it should come as no surprise that John Quincy Adams

play03:03

conveniently placed his desk right on top of this leftmost focus point.

play03:07

Next up at number three,

play03:08

everyone knows when you slam

play03:09

on the accelerator pedal in a car, the stuff in slides backwards.

play03:13

And then when you slam on the brakes, the stuff inside just keeps moving

play03:17

forward, including you, by the way

play03:19

which is why we were seatbelts.

play03:21

So then why the heck when I'm driving to the birthday party

play03:24

and I have to slam on the brakes

play03:26

does the cake slide forward?

play03:28

But the balloons actually move backwards?

play03:30

Now as for the cake sliding forward

play03:32

Well, that's just Newton's first law in action,

play03:35

which basically says all stuff is kind of lazy and wants to stay still

play03:39

unless a force comes in and tries to move things.

play03:42

And then Newton's second law tells us that the more you weigh

play03:45

and the more mass you have, the more force is required to even get you to move.

play03:49

But here's the thing we sometimes forget.

play03:51

The air around us is a fluid and it also has mass.

play03:55

It weighs something.

play03:57

This is why air pressure is a thing.

play03:59

There's tons of air molecules

play04:01

stacked up above us and they each weigh just a tiny bit.

play04:04

So we are like at the bottom of this air molecule dogpile.

play04:08

This is why your chip bag expands when you head up to the mountains.

play04:12

It's because it's moved up the dogpile.

play04:14

Now there's less air above it, weighing down, pushing in on all sides.

play04:18

And for a little proof, here's a simple demonstration

play04:21

that the air molecules around us do actually weigh something.

play04:24

When I throw this balloon at the sign, it moves,

play04:26

but it doesn't quite knock it over.

play04:28

Now, all I'm going to do is take that exact same balloon and just add air.

play04:32

That's it.

play04:33

Everything else is identical and unchanged.

play04:35

And yet now, it bonks the sign over.

play04:38

So that means we increased the mass only by adding some extra air.

play04:43

Because again, Newton's

play04:44

second law states

play04:46

the heavier, the more massive a thing is

play04:48

the better it is at bonking things over.

play04:50

So in the car, when you slam on the brakes

play04:52

it’s not just the stuff in the back that has mass that wants to keep moving,

play04:56

but all that invisible air does too.

play04:59

So the air itself also sloshes forward when I slam on the brakes.

play05:03

And since that air is more dense than the helium gas in the balloon,

play05:06

the lightweight balloon gets forced backwards.

play05:09

And that's what we'd expect, right?

play05:11

We say a helium balloon floats in air

play05:14

or this ping pong ball floats in water

play05:17

but it's almost more like the heavier, more dense thing

play05:20

in this case, the water

play05:21

rudely cuts to the front of the line

play05:23

forcing the poor ping pong ball up and out of the way.

play05:27

In fact, you can see if we lay this jar on its side.

play05:29

The same thing happens as in the car.

play05:32

When I give the jar a push,

play05:33

the water sloshes back, which forces the ping pong ball forward

play05:37

and then when it stops

play05:38

the water sloshes forward, forcing the ping pong ball back

play05:42

then for number four, we're back here on the lake

play05:44

to figure out if sailboats move by having wind blow in their sails

play05:47

Why don't they just get a big old fan like this

play05:49

to power them through the water?

play05:51

Sort of like the guy in this viral video who's using a leaf blower

play05:54

pointing into an umbrella to scoot his way around on a skateboard.

play05:58

Well, let's think this through with the simple demo of a fan

play06:01

that's attached to this train car.

play06:03

When I turn the fan on

play06:04

and it blows air to the right, which way will the car go?

play06:08

Well, of course it goes to the left because it's basically

play06:10

cutting through the air and pushing it backwards,

play06:12

which creates an equal and opposite reaction that pushes the train forward.

play06:15

Just like an airplane propeller pushing air backwards, moves the plane forward.

play06:19

It's so different than me standing on this skateboard

play06:21

And when I push watermelons to the left, they push back on me

play06:24

So I roll to the right

play06:26

NATE! AGAIN!?

play06:27

And so now let's place a brick here so this car can't move.

play06:30

And then add a second car here with a sail.

play06:33

Now, when I turn the fan on, which way will this cart move?

play06:38

Of course, to the right.

play06:39

Because all that fast moving air hits the sail.

play06:41

It's like it's being bonked by all those tiny little watermelons.

play06:45

So if we now remove the brick and this cart wants to move to the left,

play06:48

and then this one wants to move to the right,

play06:50

what'll happen when we connect them?

play06:55

Nothing,

play06:56

because it's a perfectly timed tug of war with each car

play06:59

trying to move in opposite directions with the same amount of force.

play07:02

A fan actually sort of does work to move a boat forward,

play07:05

you just have to lose the sail and point it the other way.

play07:08

But at that point you might as well

play07:09

just take that same fan and stick it underneath the boat

play07:13

so you could much more effectively push

play07:14

against the heavy water instead of just air,

play07:16

which is, of course, exactly what a boat propeller does.

play07:19

And sure enough, when I plug it in, in real life

play07:22

as you can see,

play07:24

I don't go anywhere.

play07:25

So then if we've totally debunked the idea of blowing your own sail,

play07:29

then what about that guy with the leaf blower and umbrella on the skateboard?

play07:32

Well, I've copied his exact same setup here, and I can confirm it

play07:35

actually does work.

play07:37

Yeee Hooo!

play07:38

Yeee Haaa!

play07:38

It just has nothing to do with the umbrella

play07:40

or the leaf blower

play07:41

and everything to do with the fact that this is an electric skateboard

play07:45

with the battery stored right under here.

play07:47

Exactly the same as you can see in a bunch of these shots from his video.

play07:51

Now, before we get to the last three, including answering

play07:54

if this demo for tourists is a scam, if you're like me and you love that

play07:57

ah-ha moment when you learn something new

play07:59

well, I got great news for you.

play08:01

Let me guess. CrunchLabs?

play08:02

I'm glad you said it, Jimmy. That's right.

play08:04

Because packaging up that movement is why I created CrunchLabs,

play08:08

where you get a super fun toy every month in the mail

play08:10

that comes with a video

play08:11

where I teach you all the juicy physics that make the toy work.

play08:14

Mark won't say this himself,

play08:16

but obviously he used to work at NASA and Apple.

play08:18

He's one of the greatest engineers that you can ever find,

play08:20

and he's specifically designing these boxes

play08:22

teach you all the stuff he learned

play08:23

He had this water gun that we made.

play08:25

And you can flip a switch when you give it to someone else

play08:27

and it shoots back at you.

play08:28

I mean, that's awesome.

play08:29

I've pranked you a couple times with the boxes, Jimmy.

play08:31

I know.

play08:34

So if you want to prank MrBeast

play08:35

while experiencing

play08:36

a bunch of those lovely ah-ha moments at the same time

play08:39

It worked!

play08:40

just visit crunchlabs.com

play08:42

to learn more.

play08:42

Yesss!

play08:43

Now coming in at number five is the craziest fact I know

play08:46

Imagine I just finished tying this rope all the way around the world,

play08:51

but now I just found out

play08:52

it was supposed to be a foot off the ground the whole way around.

play08:56

So the question is how much more extra rope would I need to buy to add

play09:00

to this rope to make that happen.

play09:02

Now, you might be thinking double or even triple this amount, but

play09:05

what if I told you you only need this much extra rope

play09:09

6.28 feet to be exact.

play09:12

Think about that.

play09:13

The circumference of the earth is 131 million feet.

play09:16

And yet you only need this much extra rope to lift the whole thing

play09:20

a foot off the ground all the way around.

play09:22

And what's even crazier is if you did this around a basketball,

play09:25

it would be the exact same amount of extra rope.

play09:28

Now the math is just some straightforward eighth grade algebra.

play09:31

And you can see here

play09:32

because the radius cancels out, it doesn't matter what size circle

play09:36

you use, it always works out to two pi or about 6.28 feet of extra rope.

play09:42

But if math isn't your thing, don't worry,

play09:43

because if you just pretend the earth is a square,

play09:45

it will immediately be obvious why the size of the object doesn't matter.

play09:49

So if this is my initial rope

play09:50

When I raise it off the earth

play09:52

by one foot, you can see in each corner I only need two extra feet.

play09:55

So eight feet total.

play09:57

And just like with the basketball, you’d still get the same answer

play10:00

If you try it on a smaller four-sided shape like your TV,

play10:03

which is pretty close to the 6.28 extra feet needed for a circle.

play10:08

At number six, there was a Kickstarter a while back.

play10:10

that claimed to have invented a floating backpack that reduced

play10:13

impact forces by 86%.

play10:15

Welcome to the Future of backpacking.

play10:18

You've never seen a backpack that moves like this

play10:20

or that lets you move like this.

play10:22

And this motion isn't just for show.

play10:24

By suspending the load, hoverglide reduces impact forces by 80 to 90%.

play10:29

I really took an interest once I noticed

play10:31

a lot of people in the comment section

play10:33

were debating whether or not this would actually help.

play10:35

So what do you think?

play10:36

Is this a scam?

play10:37

The case for it not being a scam is that when you wear a normal backpack

play10:40

as you bounce up and down

play10:42

with each step you take

play10:43

you're working against gravity as you move that entire weight

play10:46

up and down with you as well.

play10:47

Sort of like pulling this weight up and down with a stiff rope.

play10:50

But if the backpack was elastically suspended on a track, its own

play10:53

inertia would tend to keep it vertically in the same spot.

play10:56

So you can still bounce up and down while the pack wouldn't move

play10:59

so it’d be like replacing that stiff rope

play11:01

with an elastic one at which point you can see it makes it a lot

play11:04

easier on my arms moving up and down as the weight stays in place.

play11:07

But the naysayers pointed out

play11:09

all the pulleys, cords and extra frames to make the system work

play11:12

is still an extra 4 pounds of weight.

play11:14

And whether it's bouncing or not, you're still carrying four extra pounds

play11:18

to the top of the mountain.

play11:19

Plus, the video just shows the ideal use cases, and in real life

play11:22

it probably wouldn't work that smoothly, hiking over rough terrain.

play11:26

And I felt like both sides sort of had valid arguments.

play11:28

So as a firm believer in the scientific method, I ordered one myself.

play11:31

And then went hiking for a few miles

play11:33

with a normal backpack and then put the exact same amount of

play11:36

weight in the hover glide backpack to qualitatively compare the difference.

play11:40

So far, I don't like it. Feels like it's, like, rocking me back.

play11:44

I’m going to try jogging.

play11:46

oh that feels good.

play11:47

That's kind of the trick I feel like

play11:49

if you hit the right cadence, it's magical.

play11:51

if it's not the right cadence,

play11:53

It's the opposite of magic. oh yeah. Now it's.

play11:55

And then it gets out of sync, throws you literally off balance

play11:59

So my verdict is that on flat, predictable terrain,

play12:01

it can be beneficial.

play12:03

But on any sort of rough, sporadic hiking terrain, it's just not worth

play12:06

the extra weight in force from out of sync issues.

play12:09

And for our final science challenge, we're back here at the equator

play12:12

in Ecuador to see if this popular demonstration for tourists

play12:16

is actually a scam.

play12:18

Does the water really drain in opposite directions,

play12:20

even just a few feet on either side of the equator?

play12:23

And relatedly, do toilets also swirl in opposite directions

play12:27

in the northern versus southern hemisphere.

play12:28

Now, for the toilets, let me just debunk that myth out of the gate,

play12:32

because if you look closely, the swirl direction is just

play12:35

a function of which way the nozzles point, as you could see here.

play12:38

And with any toilet you inspect yourself.

play12:40

But what about sinks that have just a drain

play12:42

like in the demo here where there are no nozzles?

play12:45

Well, believe it or not, there's actually some truth to this idea

play12:47

because of something called the Coriolis effect.

play12:49

And it's the same reason you might have noticed weather patterns

play12:52

like this spinning counterclockwise in the northern hemisphere,

play12:56

in which case we call them hurricanes and clockwise

play12:59

in the southern hemisphere, in which case we call them cyclones.

play13:02

And the reason for this is pretty straightforward to understand

play13:05

If you imagine you have a very big sink that spans from the equator

play13:08

all the way up to the North Pole, In that case,

play13:10

a single drop of water in the sink at

play13:12

the equator here is going for a joyride really fast as the earth spins

play13:16

and a drop of water near the middle is moving at a medium speed.

play13:19

But a drop of water at the North Pole

play13:21

isn't moving at all because it's right on the axis.

play13:24

So now when you pull the plug on the sink

play13:26

and the water moves towards the middle, the joyriding drop here is suddenly

play13:29

moving faster than the slower water that was away from the equator.

play13:33

So it gets out in front of the drain

play13:35

and conversely, the drop at the North Pole

play13:38

is now moving much slower than the water closer to the equator.

play13:41

So it falls behind.

play13:42

So when all the drops are affected this way

play13:44

you naturally get a counterclockwise swirl just like a hurricane

play13:48

where the eye of the hurricane is the low pressure zone like a drain.

play13:52

Then of course, applying all this same logic to the southern hemisphere

play13:55

would of course do the opposite, resulting in a clockwise swirl.

play13:59

So does this mean that sinks do in fact drain

play14:01

opposite in the northern and southern hemispheres?

play14:04

Well, sadly, no, because the Coriolis effect is really only noticeable

play14:08

The greater distance you're moving up or down from the equator.

play14:11

So unless you have a five mile wide sink, or if you make the most perfect

play14:15

of perfect conditions, like my friends Destin and Derrick showed,

play14:19

The water is flowing clockwise due to the earth’s rotation

play14:22

The water is going counter clockwise because I’m in the northern hemisphere

play14:25

It’s real!

play14:26

this effect is way too small to have any meaningful impact

play14:29

on the swirl directions of sinks and toilets,

play14:31

at which point

play14:32

it comes down to other factors like sink geometry

play14:35

or the fact that the seemingly still water

play14:37

was actually still barely moving around when the plug was pulled.

play14:41

So then what about that tourist demo? Well,

play14:43

if you play it back and look closely, you can see the end of his pour.

play14:46

He does this subtle twisting motion so the water would just continue

play14:49

to swirl in the direction of the twist.

play14:51

So when he finishes the pour here,

play14:53

he twists this way and the water continues swirling that way.

play14:56

And then after moving the sink, allegedly over the equator,

play14:59

he finishes his pour, twisting the opposite direction,

play15:02

and then the water swirls in that opposite direction.

play15:05

In fact, you can easily recreate this demo yourself at home

play15:08

to see that by copying this method,

play15:10

you can also easily get a whirlpool in both directions

play15:14

and therefore it should come as no surprise that when I ask this question

play15:17

does it work even like if I pour the water,

play15:21

I was denied the opportunity to test and observe

play15:23

on top of all that as the final nail in the coffin

play15:26

If you actually look up the GPS coordinates of this place,

play15:30

it’s more than a football field away from the official equator,

play15:33

which means we were actually in the southern hemisphere the whole time.

play15:37

So instead of actual science, this is just an attempt

play15:39

to take your money with nothing more than a lame magic trick

play15:42

where the real magic is all that new juicy knowledge

play15:45

I just wirelessly transfered through that screen you’re watching me on

play15:48

from my brain into yours.

play15:52

It's a new year, which means it's a great time

play15:54

to invest in that passion for learning, because that passion is not

play15:57

only the main driver for why I make these YouTube videos,

play16:00

but it's also why I created CrunchLabs

play16:02

where we ship a really fun toy to your porch every month.

play16:05

And not only do you learn how to build and think like an engineer,

play16:08

but you learn the fascinating physics and engineering principles

play16:11

that make the toys work.

play16:13

Every month is a new principle, and the best part is just like

play16:16

how you hopefully enjoyed watching this video.

play16:18

It doesn't feel like learning because we're real good

play16:21

at hiding the vegetables.

play16:22

And what I mean by that is 87% of kids rate it an eight through ten

play16:26

on a fun scale out of ten.

play16:28

But also more than three out of four parents said their child

play16:32

gained a new passion around STEM and engineering after getting the build box.

play16:35

Yessss

play16:36

On top of that, each month, your box

play16:38

has a chance to contain the platinum ticket and if you get it,

play16:43

Well then you coming out to CrunchLabs to build with me and my team for a day.

play16:46

So if you want to invest in the superpower

play16:48

of having a passion for learning, just go to CrunchLabs.com or use

play16:52

the link in the video description to get your build box subscription today.

play16:57

Thanks for watching.

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Related Tags
PhysicsExperimentsEquatorMythsEngineeringPuzzlesCoriolisEffectFunLearningDebunkingScamsSTEMEducationCrunchLabsInteractiveToysEducationalEntertainment