Does Water Swirl the Other Way in the Southern Hemisphere?
ฝัง
- เผยแพร่เมื่อ 19 มี.ค. 2017
- The definitive answer about the direction water swirls in two hemispheres
Sync the videos yourself: toiletswirl.com
For the record Destin and I repeated the experiment 3-4 times each in each hemisphere and got the same results every time.
The idea that water going down a drain or flushed down a toilet swirls in opposite directions in the Northern and Southern Hemispheres has a long history. But few have ever done the experiment. Destin from Smarter Every Day and I performed identical experiments in the Northern and Southern hemispheres. What we found is the direction of water swirl in a toilet, sink, or bathtub is determined by other sources of angular momentum. However if the body of water is big enough, e.g. a kiddy pool, and left still for long enough (at least 24 hours), then the Coriolis effect is observable with water swirling counterclockwise in the Northern hemisphere and clockwise in the Southern hemisphere.
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SmarterEveryDay
Gordon McGladdery did all of the sound design for the video. We used two songs from other artists (licensed of course). Derek split the first one up so it fades from video to video, and Gordon split the instruments up on the second one. There are violins on one video and percussion on the other for example. It's really neat.
The neat earth animation at the beginning and the synchronizing timer was made by eisenfeuer.com/. He also made still images of the earth from the top and the bottom.
Thanks to Vanessa for filming in Sydney: / braincraftvideo
MORE INFO:
There was a study performed at MIT years ago (web.mit.edu/hml/ncfmf/09VOR.pdf) that explained the physics involved. We repeated some of these demonstrations, but on opposite sides of the globe…and in a way that can be easily understood.
This site is a great resource on the Coriolis effect and ways people have gotten it wrong:
www.ems.psu.edu/~fraser/Bad/Ba...
![[Live] : ONE 167 วันนี้!! "ตะวันฉาย vs โจ"](http://i.ytimg.com/vi/D9_dvfIa6Ao/mqdefault.jpg)
One of the most awesome projects I've ever had the opportunity to be a part of. Derek made it happen!
hi Destin, i'm indonesian. i tested right at equator, it just doesn't swirl at all, has no direction. why ;(
Gnouveli Post a video of it
SmarterEveryDay you both talked about how storms rotate based on their hemisphere. what would happen if this storm crossed over? or does this just not happen
Chris Bowe that's a good question and I'd actually like to know the answer, maybe one of these guys will make a video about it. It's so nice to see someone actually asking a question for the sake of curiosity in the TH-cam comments for once! Props!
SmarterEveryDay how will the water swirl on equator?
How does water swirl at the equator?
thats a really good question.
One way or the other based on even finer differences in water temperature, container geometry and initial conditions.
ArchaicMuse so in a perfect world is it possible for water to not swirl?
ahmad al khateeb in a perfect world the water would go down the drain and it would look like a cone of water. This is what I think would happen.
in perfect world,water would have laminar flow,no swirls at all.
Lives in us: 1.5 M
Lives in Austalia: 5 foot
lul
You do know that "lul" means "dick" in dutch? ;)
Lul lul lul lul lul lul
LUL
Werewolf's Channel so I should never, ever, under any circumstance, write 'lulling my ass off'??? ...good to know. I'll never be *that* stupid!
Werewolf's Channel lul
1:50 why did the American say meter and the Australian say feet 😂😂😂
Jack 64 I’m pretty sure they are both American. The way Veritasium said Australia sounds very similar to how I hear a lot of Americans say it and he also said near the beginning “in the other hemisphere” and “when I was in Sydney Australia” which would be the sort of thing someone from the northern hemisphere would say
@@mission101 veritasium is Canadian and he moved to Australia
Edit:to clarify, he was born in Australia but lived here for a very short time before moving to Canada with his family until he was old enough to move out when he finally came back to Australia.
@@kierstanfaulks then why does he say australia wrong like every other non australian says it
@@elladay7913 What is the right way to say it?
@@KristinNirvana youre meant to say- oh-stray-lia people from the US say oooh-straai-lia
At the time I hadn't noticed that Destin, living in an imperial country, used metric units and Derek, living in a metric country, used imperial units.
It's worth noting that both systems are commonly used in either countries. especially within the science and engineering fields.
+Black Fedora The two countries where the experiments were undertaken and therefore relevant to the experiment and Jimmy Greys comment - namely Australia and the U.S.A.
From what I've seen, the Anglophone countries tend to be somewhat mixed in their usage of imperial vs metric. In America, while using imperial mainly, most still know the metric system and it has some common occurrences, such as using liters often. People in the UK, while being mostly metric, have occasional thing that are referred in imperial.
The UK is a very mixed bag indeed. A person's height, weight, waist size, etc will always be quoted in feet, inches, stones or pounds (regarding weight, it is near universal to quote stones and pounds rather than just pounds) - conversely in medical practice all of these must be recorded metrically. Many people also know their weight in kilograms, but it's rare indeed for them to express it that way.
Groceries and indeed most consumer products will be expressed metrically, with the exception of beer which are almost exclusively sold as pints or half pints, milk is labelled both metrically and imperially, British people will however always refer to it imperially.
The situation is more complicated for motoring. Distances and speeds are still in miles and miles per hour respectively, most British people would also be able to refer to directional distance in yards or metres fairly accurately.Fuel is sold in litres, but fuel economy is miles per gallon. Engine size is in litres or cubic centimetres.
In my experience I think it's fair to say most British people 'think' in imperial terms though are quite happy using metric measurements or expressing them if required to do so.
Yeah, it's hard to deny that if the British didn't hate the French that much, we'd be universally using the metric system today. The British came around eventually but not before leaving themselves and the rest of the colonies in a dismal state regarding units.
still one of my all time favorite colabs!
Why is this comment three years old and only got four likes? Lol
No it has 31 lol
Now, it's 184
Now 258
Once again, we've learned something, thanks to the Simpsons.
but the Simpsons was wrong, Lisa tells Bart the toilet and sink are due to the effect but like this video says the effect is overcome by the design of the toilet/sink
Physics class. Remember?
@@V_2077 but later on they show that it's because of the design
Southern hemisphere : we do clockwise motion
Northern hemisphere : we do anti-clockwise motion
Equator : I miss the part where that's my problem
On the equator you don't get water. Except for all of the oceans, lakes and really everything.
@@cones914 Underrated comment xD
*Sad Equator Noise*
In other videos, result is opposite
Birds fly upside down in the southern hemisphere.
th-cam.com/video/Xc4xYacTu-E/w-d-xo.html
That's right. And the crows fly backwards to keep the dust out of their eyes! I've seen them myself
Been there, done that :)
Don't be stupid. In the southern hemisphere, we don't have birds because they fall into space.
Pfft, you believe in birds?
Hey can I copy your homework?
Sure, just change it a little so no one notices.
Just go to the other hemisphere and there, you have original results.
The structure of these videos so they work best when played simultaneously is actually awesome! I never watched either of them but watching this is just so cool how you take turns speaking and the video is set up so that there's always something to be looking at- it's just so immersive I feel like I don't have even a second of idle thoughts before something else happens but it's also not like it's an overwhelming onslaught of information. It's just so we'll made to keep the attention of the viewer
these two guys are really good for stage play script writers...
Agreed
legend has it flat earthers can make up a reason for this
There is a screen inside your phone that manipulates and shows you fake stuff.
they are paid actors, and they have installed pipes to pump water in to make it spin
No it is based on how the basin, or in this case how his pool was setup. The shape will determine which direction the water flows. Nothing to do with where it was located. People are fooled so easily!
@@skyisthelimitreadyornotfor2 Sigh, repeat the experiment yourself. Do it a 100 times, re-building the setup equipment each time so that you eliminate that "how the pool was setup" effect. Take a look at the results. I bet 99% of the time you'll get the same result.
@@zirkoni42 r/wooosh
the way how the guy on the left is so close to the toilet when it flushes makes me extremely uncomfortable
And then he wipes his lip
steph k the way you haven't noticed that I exist makes me extremely uncomfortable 😍😘
This needs to be top comment.
Love clean toilets
technically speaking, there is no such thing as clean toilets.
It's interesting to note that at the level of a tornado, which is considerably bigger than a bathtub but still pretty small on the scale of the Earth, about 95-98% are said to rotate cyclonically (counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere), but there is that small fraction of anti-cyclonic tornadoes.
Yes, I've heard of these "reverse" storms, but I never saw a percentage given. At a hurricane level, there has never been a "backwards" example in all of human history.
@@kdwaynec Cyclones (hurricanes in the southern hemisphere) rotate clockwise. All the science websites say its due to Coriolis effect. This experiment wasn't needed.
If all tropical cyclones/hurricanes rotate counterclockwise in northern hemisphere and all cyclones spin clockwise in southern hemisphere, i don't see why there'd be any doubt.
I served a mission for my church in Brazil. One of the first things I tried, was fill a sink with water, let it sit over night, then pulled the drain plug with a string, rather than reaching in. It indeed swirled clockwise. I tried it several times with a sink behind the house, that is normally used for washing cloths. It too drained clockwise. The toilets were no indicator, since the offset jets determined the direction of the vortex when flushed. I was in Minas Gerais, which is far enough south, to make it pretty reliable as long as the water had time to completely stagnate. I even placed a board over the outside sink, to make sure no wind could disturb the water. If you drained the sink immediately after use, any turbulence in the water would override the effect, and it would swirl in either direction, It didn't take much, to influence it.
It’s just not true.
@@0Logan05Did you try it for yourself?
Fantastic demonstration. Thank you for the effort you both put in to make this video available.
And with that, the flat earth 'theory' goes down the drain :) .
Nuh uh, just because the earth is flat doesn't mean it doesn't spin! :P
Nah, it's banana shaped, and dipped in herbs and spices for best taste ;) .
Let's wash our hands of these puns
We wouldn't want this thread to spin out of control
devzer0 i think its pretty washed up now
the world need more videos like this...scientists in the bath and on the toilet.
this is really awesome and incredibly well done! So much work to cut in synchronized, really really cool!
Just watched this for the first time. I really liked the Synchronized format of using 2 videos. Super cool!!
You might get more consistent results with a very long pendulum (Foucalt's pendulum), but that would be more expensive to constructs. There is one in my city and it is built into a tower so it is shielded from weather. The pendulum swing is steadily altered by the Coriolis force, which can be observed by a pattern drawn by a stream of sand coming from the pendulum weigh.
More important that is not the question. The question is about liquids. This remembers me when students do all the calculations properly on a math exam and then forget that the question was about the diameter and not the radius of the circle
False. If you see a crane when it's not working the ball on the end of the line does not move and its way bigger than a display in your city.
@@crownnothin, wrong case. Pendulum swing precession applies to those already swinging. Coriolis effect won't affect still object.
@@crownnothin - "False. If you see a crane when it's not working the ball on the end of the line does not move and its way bigger than a display in your city."
Cranes that aren't working don't leave an unburdened line all the way down, lol - they keep it hoisted to the top so it doesn't like, break things, or itself, when not in use.
The other problem is as they mentioned above, if you hang a line outside it'll have things like wind pushing it around. An openly swinging crane line isn't going to show the Coriolis effect because it'll be swinging in the wind (hence, they don't leave them hanging when not in use), which is why the Focault's pendulums are built in towers so they can be shielded form the weather.
@@KingBobXVI > which is why the Focault's pendulums are built in towers so they can be shielded form the weather.
Yah, my high school had one in the atrium of the "science silo" -- a round wing that contained most of the science lab classrooms. (There was a fad of building science classrooms like this in the 1950s and '60s.)
Don't know how I didn't see this 4 years ago, but thanks TH-cam recommend, you were actually helpful for once
Excellent demonstration, and I like the graphics of the poles, explaining how this phenomenon occurs, Good Job, you guys, keep up the good work....
Dude this was awesome!! Never seen videos synchronised before. Fantastic!
Great, and thank you! Every physicist knows this, but there are so many counter experiments with additional forces involved. It's the Coriolis effect, or Fouceaults pendulum if you like.
Wonderful video, and clear victory for physics. Added it to my favorites and physics lists.
This is fake. The water would of flown onto the sky in australia.
Electrified Heart lol
Nathan Weatherly that’s not a woosh.........
@@nw3473 he just don't know the reference
Words fail me on this.
He had us in the first half
You guys have the BEST video on this question. I "seemed" to observe that the water drains from my Canadian tub in one direction one day and another another day, so I needed the science.
What a cool idea and cool video! Thanks for putting these two together
Too cool! Coririolis rock! The Earth rocks! You guys rock! Well done. I FINALLY got hub to understand this principle (I’m a MSc in applied mechanics/combustion engine engineer/ and he is an archeologist). A million THANKS 🙏 to both of! This version (showing both besides each other) was very pedagogical.
Cue the flat earthers!
nah, make sense on a flat model as well. The rotaition could be the Sun, travelling over the equator. Everything on the left would gain a small pull on their right side. Just like a passing ship, causing turbulence on each side, with opposite water-spin-direction. The effect might be proven, but is the spin too? Maybe we can try it with technology of our century... just wondering.
Sortaray flat Earthers surely can't believe in the mass to gravity correlation, right? Because what the hell is under the flat earth? Infinite mass?? 😂
how could i forget the anwser to this question... and why do you want to know in the first place?! Im not a believe-expert like u, i guess.
Sortaray are you talking to me? I want to know because my brain functions on logic.
we tried doing things with modern technology. but flat earthers are convinced those are conspiracies or everything we get from them is fake
Very smart innovation, I admit I didn't try to play both videos when I first saw them but it turned out that i have missed something. when played together it added a whole new insight. Thanks
Awesomeeee, it was difficult to grasp de idea without seeing it, your amazing as always :)
I literally posted both of the old videos yesterday, when someone posted to fb a video where people walked across the equator and supposedly proved the coriolis effect, but they were pouring the water in the complementing directions. People were saying, "Mind Blown!" and other ridiculous exclamations, and I just sat there wondering how I could tactfully tell them it was a trick. Thank you for combining the videos!
Viola James good :) Yes, so often people miss the key factors. Could include myself as well, in some topics I don't understand so well. I'm also happy this video was released. I had been wondering if it is true or not. This confirms it pretty well. I mean, to me it looks valid. It may not be scientific as a test (two) arrangement, but it is at least a good effort and well explained.
The effect would be even less near the equator because the ratio of distances to the axis is closer to one.
I think the geometry of the drain can also create vorticity, as in case of the wings of an airplane, the no-slip boundary condition on the surface of the wings is a source of vorticity even in previously irrotational velocity fields (see for example the Kutta condition). What I mean is if you have a drain formed as a Kaplan turbine for instance, even if the turbine is standing, the flow will begin to rotate automatically and that is not becouse of the Coriolis force.
This seems too small of a distance do you have any Coriolis effect visible
Ding ding ding!!!! We have the winner!
I just watched this and the first thing that popped into my head was any irregularities in the drain, the bottom of the pool that water is flowing over, or even the direction the ball valve opens could start the motion in one direction.
Further exemplified that the rotation happens at the drain itself. Simple scale analysis shows that Coriolis would not be affecting the water at this distance.
@@grillmaster95 You would only see the Coriolis effect at/near the drain as the reduction in radius is needed to markedly increase the otherwise very small difference in angular velocity of the water going around the outer edge. Coriolis effect on this scale is tiny, but when you have a radius reduction on the order of 50:1, the magnifying effect it can have on angular velocity is rather extreme.
A fun way to prove the Coriolis force! the visual explanation that follows makes it all intuitive. Thanks for posting
Still awesome!
Hello!
Wow hi
😍😍
The King of Random Sharap
Wow I didn't know you watched these videos
Have your done the experiment a hundred times, and then swap pools, and then a hundred times again?
Yan G yeap, that would be the very minimum to ensure there are no other effects at play (or even slight variation of the pool shape). Even then I'd bet the results would be close to 50-50. After all it's a chaotic system and the scale is *far* too small for the Coriolis effect to actually matter (at larger scales we already know it does).
Oh, and waiting for 24 hours for any initial rotation to settle is ridiculous. I have no problems with the video other than it implies this is proper methodology.
clear science right before your eyes and still arguing a moot point...read the description please!
phil tripe, I have higher standards for what constitutes "science".
@@jasondoe2596 no one needs your science.earth is spinning for a fact.so if you do this perfectly you will get the same result for 1000 times
Yan G
They did do the experiment multiple times 😀
This was amazing, Derek!
Great , was searching for the other video to show to a friend. This is even better to kickstart the conversation
“Wish me luck Destin”
“Good luck Derek”
That was so perfectly done lol
Very good video, well done guys! I’m just wondering why you didn’t add the dye before opening the drain, maybe wait the same time you deemed the water had no spin then add the dye, wait a few hours to ensure no motion and then open the drain?
But the video is great! I really enjoyed watching and I feel richer now 😊👍
If you add the dye before opening the drain, it dissipates and you can't see it, and/or you introduce motion to the water before the effect can start.
Adding it after it starts, allows the water to build its own momentum first. A few drops of dye isn't going to change the direction of kilograms of water that's already moving.
A long time agi I worked in a laboratory that studied airflow in buildings. We had a symmetrical air room there where we could measure air speed through the entire room which was blown evenly from one side in that room. We noticed this effect as well. We had not enough data to prove anything, but interesting it was.
Great description. Well done demonstration!
Respectfully, you haven't eliminated all variables. A slight angle of the drain, thermal differences from sun/shade, slight tilt to the pool, manufacturing differences in the pool all could affect outcome. This body of water is too small to be affected. Hurricanes are subjected to very fast upper air winds that get the momentum started---not merely the earth's spin effect on the water. I think you'd have to build 100 pools and conduct the experiment 100 times to actually verify a real statistical difference beyond chance.
I am a huge fan so please don't think this comment critical.
Your points are correct, however, I'd state that this is a perfectly viable experiment.
I think the idea was to remove as many variables possible within a reasonable budget just so the Coriolis effect can be observed.
If it helps at all, in the description it reads: "For the record Destin and I repeated the experiment 3-4 times each in each hemisphere and got the same results every time."
Boredness What does it matter when the effect is too miniscule to observe?
You are correct. The pool is far too small a body to experience the effect. I suspect there is some flaw in play---not intentional, but something. Air current possibly. Even in meteorology, the effect is smaller than most believe and is mainly due to temperature zones which set the motion in the opposing directions for each hemisphere.
It would be interesting to include a discussion of the great air masses (and some currents) flow in the North Atlantic (clockwise) and South Atlantic (counterclockwise), the opposite of what is shown here.
I can't name a better duo for science videos. Also, 5 minute video = good. Just need something over lunch and the length here is perfect.
Thank you you finally answered a question that I’ve been wondering about for 7 years
Keep wondering then because if you watch it again you’ll notice that they got the direction of spin wrong. It’s supposed to be clockwise in the north not south. Hahaha
Oh, I've already seen this video, lol, don't know why this wasn't released earlier, either way it's cool! :D
I remember this and it is still, to this day, one of the coolest things I have ever seen on youtube when I synced the two videos and had one full screen on each of my dual monitors.
One of the best videos of this channel.
So coriolis-effect does the effect even that small distances of movements too. So interesting 👏 Thank you for this video 😊
This idea is so weird to me, because every toilet I've used doesn't swirl in any particular reason. The water just kinda goes everywhere.
It is because it is the size of the pool that makes it. A toilet is simply to small. You need at least large lakes to get it big enough.
I agree with Eleanor. I think Veritasium headlined toilets mainly cos it's kinda smutty, even though the vid itself is excellent in my opinion. I agree with Filip that size is important. Not just the size of the body of water but also that of the drain hole, take a look at Google images of reservoir drain holes, where the surrounding water doesn't appear to swirl as it goes straight down the sides. I suggest elsewhere it's the interference caused by a narrow hole that results in swirl in one direction or another.
I have physically experimented with it. A pool a few meters across could be made to swirl in different direction by manipulating it a bit. But if in sizes of several kilometers across, the earths rotation would most surely be the dominant factor.
The experimenters in the vid took a lot of trouble not to manipulate the water themselves, by leaving it to settle overnight, and draining it with valves located outside the pools. But I guess you're saying the pools themselves are still far too small to convincingly show up the earth's rotation effect. What do you think of my point about drain hole size as a factor in swirl, leaving aside the question of direction for the moment?
I don't know but I believe the drain hole is an important key to the rotation in small pools. But someone should run the numbers on this, cause I really wanna know.
By far my favorite collaboration on TH-cam ever.
Both these channels are true assets of the internet! Keep going brothers!
I had heard that about the swirls, and suspected the same reason behind it. Thanks for showing it!
Never thought I would watch a video of a man staring at his toilet water swirl down the drain.
I don't dispute the explanation of the coriolis effect, but I have to question whether the speed difference over a couple meters is significant. (Distance from pole to equator 10M km, speed at equator 460 m/s, therefore each meter represents an average change in speed of .00005 m/s per meter.) This experiment could easily just be a fluke. Before jumping with joy, I think multiple better controlled tests would be needed.
this is why they said that the effect is so minor that in general, it gets lost in other factors that influence the way the water drains. the moment you throw in any disturbance to the water before the water starts to drain will alter how it drains WAY more than the rotation of the earth.
+Ursinos I am aware of that. I have discussed this in another thread, and there I even stated : "The paradox of my criticism is that if everything were perfect I would expect the result that they got. I just don't believe that they proved it." And there's the rub. The effect is so small that I'm not convinced that this experiment can eliminate other factors that influence the way the water reacts. Even convection currents due to where the sun is shining could be a larger effect.
But my position may be weakening. In that other thread someone posted this reddit thread : www.reddit.com/r/IAmA/comments/38gekk/iama_guy_who_makes_science_videos_on_youtube/cruudik
They repeated it 3 times time though, and still same results. So this happened: 1) the results line up with their location 2) same results 3 times. What's the chance to have it by accident? Should have tried with different pool setups/at different times (day/night) though to be 100% sure.
KonstantinGeist Need more data!
CONSTRUCT ADDITION PYLONS
Thank you for clearing this doubt I had for sooo long! Very interesting! 🥰
this is so cool. its such a basic experiment but very good to watch.
It's more fun to find Coriolis effect in long range precision shooting
It is about size. The bigger the pool, the bigger the Corriolis effect. If the pool gets to slow, other factors like micro currents, friction, air draft, the shape of the container etc will determine the rotational direction.
I once cut the base off a 5 gallon drum, wrapped copper wire around the neck and hooked it to a car battery. When I switched it to positive it increased the up the spin rotation and when I hooked it up to negative it just went straight down. I don’t remember how well I controlled the experiment to not have any motion in the water prior to pulling the plug. However, the effect that the positive and negative electric current had was repeatable.
I was always confused about this thanks for the explanation
Mind Blown
This level of commitment is the definition of loving science
Excellent video.. thoroughly enjoyed it
2019 and still AMAZING!
2021 and still AMAZING!
What if a tornado travels from the northern hemisphere to the southern hemisphere? Does it collapse?
It's impossible as the coriolis force dictates that the path of hurricane would move towards the poles away from the equator
Interesting...
I don't think that happens, we always see tornadoes or hurricanes making landfall in coastal areas away from the equator.
Actually making this happen would be a problem as the larger scale rotation of the wind would be pushing the tornado away from the equator. But lets just assume for a moment you could then no the tornado still wont collapse it's not the vortex rotation that's driving it it's the atmospheric inversion (The fact that warm air high pressure air is trapped bellow cold low pressure air). So long as the inversion remains the tornado would keep going though it's vortex should begin to slow and even eventually stop and start going the other direction if it lasts long enough which is pretty unlikely it has some pretty significant momentum and they just don't last that long.
Brian actually, tornados are too small to predict their rotational direction. On this small a scale you need really calm initial conditions to see an effect of coriolis (like they are in this video - they let it sit for quite some time and then don't even dare to simply pull the plug) you don't have such conditions in the free atmosphere.
It's different with the much bigger hurricanes. They rotate ALWAYS in the direction dictated by coriolis and can't exist near the equator (between ~5 degrees north and south) due to the lack of coriolis force. So yes, a hurricane would break down but no, a tornado wouldn't.
That's a very interesting video and one that has left a few questions in my mind. If the water were to emerge INTO the pool from the hole in the bottom, do you think it would begin to turn counterclockwise in one hemisphere and clockwise in the other? I'm asking because weather events are made up of either an ascending air mass or subsiding air mass. When the air mass is subsiding it moves along the surface towards the lower pressure area away from the center. When the air mass is ascending it moves along the surface towards the low pressure in the center. Therefore I'm wondering if the water were to move away from the center of the pool would it rotate the other way?
Probably not. Two problems. First, Your in-flowing water would start out so turbulent that it would completely overwhelm any Coriolis effect - it obviously hasn't been sitting still for any time at all.
Second, pumping water in from the center you'd get an angular momentum DAMPING effect as the radius of the pool increased, as opposed to the angular momentum exaggerating effect that you get when you reduce a radius.
The Coriolis effect is already incredibly minute at these scales, so you need the reduction in radius in your experiment to make it visible at all - going the other way would make it impossible to detect.
@@Vastin Hi Jesse. Thanks for your reply.
Cool and well put together experiment! 👍
Thank you so very much for clearing this up. When I was in the USA I was looking for it to swirl the other way!
aah, I remembered this, it was hard to watch this with my laptop and phone at the same time XD
If you try to flush water inbetween the hemispheres it starts floating and attacking people
That was great! This was the best way to explain it to the kids in my family! Thanks, guys!
This is a new and so creative way to make a interesting video
them : we did it, we've eliminated all variable.
Dye and Wind : cough cough, am i a joke to you ?
Dye is not a variable in rotation. Wind, possibly. Depends on if it was windy. But these are pretty smart guys. I'm sure they took wind speed into consideration
cool, but I hope they ran the test at least 5 times to make sure it wasn't just coincidence. (I'm not totally sure the pool was big enough)
My thoughts ! in science a proof is something reproductible, so ...
That would be a bit of a waste of water, but I expected it to be done at least twice
@@fruz1378 Read the description. They did repeat 3 to 4 times.
@@omarahmad3878 good catch, it does not show up until one clocks on th "show more" button.
With Coriolis is not a matter of length alone. Velocity is inportant too. I was surprised as well by the small dimensions of the pool but the water is flowing very slowly. I'd like to know the Rossby number which will give you the importance of Coriolis forces over inertial ones...
This video really helped me to solve my question of this vortex, thanks
Beautiful simple explanation!
Whenever someone is fooling around in class, my science teacher says "your grades a spiraling down into the upside down swirling toilets of Australia." I'm not kidding.
I can imagine the neighbours looking out their windows to find a grown man screaming out science stuff beside a colourful kiddie pool.
Very interesting. Great video guys.
This was awesome!!!! The coolest effect
SciShow: You just got served.
This video and experiment are great! But, as with most scientifically focused videos, too many of the comments leave me questioning the future of humanity.
I’ve actually seen this effect demonstrated by the equator in Ecuador. Same basin on legs with drain into a bucket underneath. They added flower pedals to see the motion. They did it about 20ft north of the equator and then picked up the basin and repeated the same experiment 20ft south of the equator. They effect is still apparent even that close to the equator.
Are you sure they weren't cheating somehow? I think the effect is effectively zero near the equator, as all parts of the pool are at very nearly the same distance from the earth's axis.
@@andersmusikka one might think. I know I would. I saw it with my own eyes. They used the same basin so the same constants on both sides. It was more of an educational demo as opposed to a magic trick.
Wow u guys helped me relook at some puzzling anomalies in the design of pre-Ancient waterway architectural knowledge and design.
The Coriolis effect is in my top 20 favorite effects.
What are the other 19?
(I would like to read about them)
@@anujgupta6347 same
"The Coriolis Effect is real." Yes, we already knew it was real. Cannon-balls and all.
u clearly havent met r'tarded flat earthers they believe nothing
I know this is a quite old video and you do an amazing job explaining this in understandable terms!
Perhaps you've already done so, but I'd love to see a video in your style thst explores the math/physics behind this the coriolis effect.
On a bathtub scale, it's easily explained thru Newton/laws of motion. But (admittedly as an armchair math magician..) I feel like I learned that rotating objects on the the surface of a sphere are also subject to inertia/torque/angular acceleration physics. And the same type of effect is observable within magnetism math on the planetary scale that can be visually represented by the polar aurora.
I think you have a talent for explaining things in an understandable way.. And would love to watch a video where you explore the different observable maths/physics behind the coriolis effect on larger and larger scales within the solar system!
I think there is an interesting mine of content to explore around this phenomenon, how it manifests, and why. From the way water goes down my drain to how solar radiation is twisted around every planet... It could be an interesting multi episode deep dive!
Just a thought! It felt up your alley and it's a series I'd Def enjoy watching. Not at all trying to tell you what to do!
Love your channel. Keep up the good work!
Thanks to both of you !!
So the swirl of water would be the most intense at the poles/rotational axis of the earth?
Yes, that is right. It's why a Foucault pendulum rotates the most at the poles, and not at all at the equator.
seasong There would be 100% speed difference as it would be going the same speed in the opposite direction
Edit: angular velocity or whatever, not technically speed
it seems that, we're asking the same question yet conclude a different hypothesis
This effect is caused by the difference in linear velocity around the axis between two positions with the same angular velocity.
That difference is caused by them being at different radii from the axis.
Distance from axis on the surface of a rotating sphere is proportional to the sine of the angle from the pole.
The greatest difference in linear velocity will occur where the greatest difference in the sine of the angle is.
The angular size of the pool being constant, this will be where the gradient of the sine graph, dsin(x)/dx, is at its greatest.
dsin(x)/dx = cos(x).
cos(x) is at a maximum where x = 0.
This effect will be strongest at the poles.
Further, cos(90°) = 0, so at the equator there'll be no effect at all.
It's all a matter of perspective. One spins one way, the other spins opposite. Or does it?? Technically, they are spinning the same way relative to each other.
Make a fist with your right hand, with your pointer finger, and point to the floor. Spin it to the right and you have clockwise. Now carefully turn your hand over so it points to the ceiling, and keep spinning. Is it going anti-clockwise? Turn it over again. Now it's clockwise, yet it's still spinning the same direction.....
Correct, our perspective changes depending which hemisphere you do the demonstration.
Great point. I just made a similar one about cyclones a moment ago before reading your comment. Perspective always has to be emphasised when we're talking about such subjects.
I was just wondering this, and had a hard time visualizing this. The common sense tells us that they are spinning in the same direction, but the fist and finger experiment helped a lot. Thanks :D It's so weird.
You almost had this correct. Turn both hands so they point at each other. Wiggle your fingers going forward or backward as you like, but the same, mirrored. Now keep the fingers going and turn your hands down to see them spin opposite clock directions. That's what the Coriolis effect does to fluids on either side of the equator.
You guys are better advertisers/marketers than anything else.
F*ing awesome vid! As is the whole channel! Dude(s), your doing some amazing job!
this must be the world's first double synced repost
Wondering if, when you repeated this experiment, you completely rebuilt and re-leveled the base of your pools or even used completely different ones each time. As from what I understand of the coriolis effect, your pools are far too small and would drain far too quickly to be significantly affected by it. I think what you got was fairly lucky and not a repeatable result. Would love to see someone actually do the math on it.
This deserves a follow up video in which you position the pool so that the drain is either perfectly at the equator or at either pole so that the outer side of the pool is as close to either/the other pole as possible to see if the angular momentum cancels out or not.
Best youtube collab ever made
Fun fact : Due to the coriolis effect, the hair on men's is swirled in different direction. You can look at their occiput and see the direction will vary depending on which hemisfere you are or on which hemisphere they've been living