@bigboam Haha, they may have mentioned conservation of angular momentum, but it has nothing at all to do with the Coriolis Effect! Its only a perveived deflection when viewed from a rotating/non-inertial reference frame, nothing at all to do with conserving of angular momentum. What you need to do is research Flat Earth, as we never see a plane deviating due to the Coriolis Effect, because the Earth is flat and stationary!
Pressure gradient (and friction as well) are also playing a role in the direction of winds within a hurricane. Coriolis is only one factor. Winds "want" to move directly to the center of the hurricane (directly towards low pressure - aka its pressure gradient). However, the Coriolis deflects the path of the winds to the right a bit, not allowing the winds to go directly towards the low. This results in counterclockwise flow around the low pressure center. Hope that helps!
Roger, good question! my background is in meteorology with advanced research in severe weather (tornados, hurricanes). to really get an understanding on an answer relating to your question would take too long for this 500 char. window here. it's a complicated answer that involves more than just the 'coriolis force' - it also involves other forces all acting together at the same time (magnus and rossby forces, reynolds numbers, fluid dynamics, temp.& pressure, topography)- more than newton's laws
storm winds are the resultant of the gradient force caused due to pressure difference and the coriolis force. thus if you look at the centre of storm (direction of gradient force) and imagine that coriolis force acts to your right hand the resultant motion would be counterclockwise in direction
@lEtudel This is difficult to explain w/o visual aids, but I'll try anyway. In a low pressure system, air is coming in from everywhere around the system. On a sheet of paper, draw a circle with an L in the center to represent the storm. Now, draw arrows all around the circle pointing to the L. For the NH, the CF is to the right, so on the arrows you just drew, draw more arrows pointing to the right of the direction each original arrow is traveling. You'll notice this causes a CCW spin.
After 2:48m the video stops. The audio continues normally and the individual frames can be seen if you hover over the video, but the last *moving* image seen is the first line of the angular momentum explanation. This happens in both Opera V12 and Firefox V21. (July 2013)
Great video, I use it a lot in my college geography class. Only one problem - rotational velocity at any point on Earth's surface (angular displacement per unit time). The narrator often confuses rotational velocity with linear velocity, which does vary from latitude to latitude.
When moving from equator to one of the poles, objects get a higher rotation frequency than that of the earth, so they get deflected in the same direction as earth’s rotation, which is to the east. For objects moving from equator to the North Pole the east is to the right, for objects moving from equator to the South Pole the east is to the left.
@shootingnerd shooting, it's a good question, and although you get the same type of effect, the underlying physics is much different than described in this video for zonal (east-west) movement. It's because a westward moving object is moving slower than the Earth, and an eastward moving object faster than the Earth. Ultimately, you adjust latitude by allowing the centripital acceleration to be sufficient to balance the gravitational force
That would send them further off path. The counter clockwise motion literally counteracts the effects of Coriolus. Offsets it so the low pressure system would stay on track or not drift.
Nicely explained. Thanks! Would be good if you could elaborate on hurricanes though, e.g everything in the northern hemisphere deflects to the right, but the hurricanes cyclonic circulation is anti-clockwise. How does the right deflection invoke an opposite spin direction for wind??
Friction between the air and the ground. The part further south gets dragged along faster with the ground, so the rotation is counter clockwise. That's my guess.
Because, as the video explains, the 'Conservation of Angular Momentum' means that the parcel of air tries to maintain its angular momentum and moving north or south in the Northern Hemisphere, the air parcel will try to steer itself in a right-handed direction.
In consider yourself moving away from the equator. If you go south, away form the equator on the southern hemisphere, the direction you need to move to keep a same angular momentum is the direction of the earths movement, so to the left. If you travel north away from the equator, on the northern hemisphere, you still need to move towards the direction of the earths rotation, so to the right.
Put very simply, it is that an object in motion tends to move in a straight line. The earth is turning underneith the moving objevct. Vizualize a cannon sitting on th north pole, firing at a target 20 mi away. Lets say the shell takes 30 seconds to reach the target. Th earth is turning counterclockwise--at a rate of 7.6 feet/sec. Where does the shell land?
When the object moves East, there is no change in radius (you stay at the same latitude). As the mass is constant, the conservation of angular momentum suggests that the velocity remains constant. So why does the corriolis 'force' continue to deflect the object to the right, towards the South (on the Northern hemisphere) ?
Imagine a world where videos like this had 1,900,000,000 views and 'Gangnam style' had 280,000.... question though: Is air moving downward from the north pole because downward is outward in this case (thinking centrifugal force)? And when it creates a cyclone pattern does it move to the right initially as it it move south and left as it circulates northerly again for that reason, that it is circulating north in that hemisphere of the cyclone pattern.... as it would if it were in within an anti cyclone in the southern hemisphere?
They say that a mass following any latitude (other than the equator) eastward coriolis-e. will turn it to north, in norhern hemisfere. If so, the coriolis-effekt is not caused by the different surface-velocity on earth. (Which is the normal explanation of the coriolis-effect) They say also that the coriolis-effect is less (0) on the equator and maximum om the poles! But if you place a ball on the pole and turn the sphere(or board) as fast as possible the ball will stay on the pole. Explained?
Nice video, but for me leaves more questions than answers, for example: 1. The merry-go-round demonstration contradicts the physical explanation regarding conservation of angular momentum. The reason the baseball circles is simply because it is following a straight line relative to the ground. If your frame of reference is rotating, then in that frame of reference the straight line is a circle. This has nothing to do with conservation of angular momentum: the ball is just traveling along a straight line at constant linear velocity. 2. "The Coriolis force increases with speed of the object" This would seem to imply that the deflection in the movement is greater when the speed increases. But obviously, this is not true on the merry-go-round. If you shot a bullet across the merry-go-round, there would be practically no deflection at all. The deflection would increase with the speed of the rotation, not the speed of the object. If the speed of the projectile is very high relative to the speed of rotation, then it seems we could practically ignore the rotation and there would be no Coriolis force. This leaves me with the impression that the merry-go-round demo has nothing to do with the Coriolis force. Can somebody explain?
Bill Ravenwood no. These are the precise questions flat earthers ask, in which nobody provides an answer to. There is no answer to your question if our globe is the correct model of our planet- it is impossible.
Well, you managed to greatly misunderstand and misinterpret what the video was all about. Having said that I admit some points made in the video are terribly presented so as to confuse rather than clear up any confusion. 1. The baseball doesn't follow a straight line relative to the ground. It would if it didn't make contact with the surface of the marry-go-round (i.e if it was thrown). Even if it's just placed on top, it would still make a circle relative to the ground. The real trajectory of the ball in the video relative to the ground is a semicircle. However there is some sense in saying "this has nothing to do with the conservation of the angular momentum" as the ball, being in contact with the surface, is actually moving in the opposite direction of rotation because of inertia. Just like standing passengers in bus that lurches forward fall in the opposite direction of the movement of the bus. 2. Truthfully I had hard time understanding the logic behind that sentence too. It just makes no sense until you think about the path travelled (greater speed = longer distance= moving closer to the axis=greater deflection). It has nothing to do with speed really so the author is wrong. It's all about the path. Even if the object is travelling slowly, if it covers more ground ultimately it would still amount to greater deflection. If you shot a bullet across the merry-go-round then the deflection would be minute but that's because the bullet isn't part of the same frame of reference.
Bill Ravenwood 1) Your reasoning is fine, aka curved space-time in general relativity. Another is coriolis force in classical mechanics. It's fictitious, appears to exist in rotating ref frames (and for newtons laws to work). Vid relies on angular momentum at points where its irrelevant. 2) You need to sit near the centre of a merrygoround and fire the gun; bullet appears to take a wicked deflection. For outside observers, bullet and ball take straight paths. Merrygoround's angular velocity (rate it completes full turns) affects the force, as does object's velocity.
Yes, Bill, you are absolutely correct! The merry-go-round is simply a demonstration of Newton's first law of motion that happens to look like Coriolis force at work. The confusion happens when people like you are smart enough to figure out that in both cases illustrated in the video, the ball is actually just going in a straight line through space, which you can easily see from the bird's eye view. In one case it flies in a straight line and in the other it just rolls in a (relatively) straight line. (The apparent motion of the ball as viewed from a seated position on the rotating merry-go-round would be identical if the ball were thrown over the center of the ride by a distant observer.) So this is not an experiment showing actual Coriolis force being applied. The reason for this is that as soon as the ball is released, the centripetal force disappears and it's momentum becomes linear. Yes, there was angular momentum but that was preserved by this transformation. The explanation of that is a little abstract, so just accept that the ball is no longer part of the rotating merry-go-round system; it's simply a free body moving through space with an angular velocity relative to the center of the merry-go-round. Trouble is, while it is related to angular momentum, angular velocity is not a conserved quantity - so there will be no Coriolis force applied with respect to the rotation of the carousel. On the other hand, if you can overlook the fact that you are not observing actual Coriolis at work, it's still a pretty good demonstration of the effects of Coriolis, because the behavior of the ball is the same as if you were observing real Coriolis. The only difference is that instead of applying an actual force to the ball to physically curve its motion through the rotating reference, the merry-go-round is simply moved underneath relative to an object moving in accordance to Newton's laws. In other words, the apparent path of the ball in the experiment follows an actual path that would happen in an actual rotating system. But I get your frustration, because using a visual trick to illustrate the effect of Coriolis makes many people, even some fairly knowledgeable on the subject, believe that Coriolis is only an apparent force. Unfortunately, it is nearly impossible to observe actual Coriolis on such a small scale. I can assure you that Coriolis is very real - it's just not being observed in this example*. If it weren't real, there would be no force to oppose an atmospheric pressure gradient force, and since F = MA the mass of air would accelerate and move directly from high to low, equalizing the pressure difference almost immediately. Since it does not accelerate in this manner, there must logically be some force acting in opposition to it, and that is indeed Coriolis. Acceleration still occurs, but not as a result of a change in speed; the acceleration is due to a change in direction, as the force is applied at a 90 degree angle to the initial movement of the air mass. So no energy is added or removed from the mass; it is only driven off the direct line from high to low pressure. This applied force increases steadily as the air mass moves poleward. This is because as it does so the mass is getting physically closer to the axis of Earth rotation. You can see clearly that in this case the air mass is not anything like the ball in the video because it is rotating with the Earth as it tries to accelerate from high to low. Therefore it is part of the rotating system and as poleward advection occurs, the angular momentum of the air is conserved as in the example of the ball on a string accelerating as the string gets shorter and this increase in speed is instantaneously met with increasing Coriolis force to change the direction and maintain a constant momentum, which is Mass x Velocity, or p = mv. So it could be said that Coriolis force is just a term for Conservation of Angular Momentum as realized in a rotating spherical reference. * Notice I said it isn't OBSERVED. I didn't say it isn't AFFECTED. The ball actually is affected by Coriolis with respect to it's angular momentum referenced to the Earth. It is not affected at all by its motion referenced to the merry-go-round. But you can't observe the effect of Coriolis on the ball because it is so infinitesimally small as to be nearly immeasurable. Thus, the parlor trick has to be employed to illustrate on a small scale what actually happens in full scale. Taking this explanation a step further, it would still work in the southern hemisphere, where actual Coriolis force would act to the left. But on a merry-go-round moving counter-clockwise in Australia, the ball would still appear to move dramatically to the right with respect to the carousel, even though it is actually moving an un-observably small amount to the left with respect to the correct and actual Earth reference. In other words, everything I'm saying here can be proven simply by duplicating the video experiment anywhere in the southern hemisphere. Or, albeit probably less convincingly, by instead turning the carousel clockwise any where in the northern hemisphere and observing an impossible-to-achieve-by-Coriolis left apparent deflection while the actual deflection would be very slightly to the right.
You're correct that the parcel on earth will go in a circle ignoring centrifugal force because of the oblateness of the earth. That's not true about the merry go round. On it, the ball does not go in a perfect circle in the frame of reference of the marry go round because of centrifugal force.
I'm not a physiscist or whatever, but i think it's becuase every object tends to maintain it's linear velocity (angular velocity[costant] x radius[distance from rotation axis]). So, if an objects moves from the equator to one of the poles, the points located in the imaginary line it covers will have a linear velocity wich is inferior to the one of the object we are considering, so the object will Always anticipate those points. If you consider the trajectory this go left in the Southern...
And in answer to gafodde, no, because for the Coriolis effect to come into play, the parcel has to cross to the other hemisphere for it to curve the other way. Therefore, it will stay on that hemisphere, as the parcel cannot be in two hemispheres at once. Also, if you made sure that it was exactly at the equator, there is no Coriolis force at the equator. Hope that answered your question :)
can someone help explain at the southern hemisphere why the winds deflect left? i can understand at northern hemisphere , where the velocity is higher , and hence , pushes the wind movements to the right. But if the earth rotated rightward , why is it that at the southern hemisphere , the winds deflect left????? I really need help on this .
THIS IS THE ONLY VIDEO THAT ANSWERS *WHY* THE THING GOES RIGHT IN THE NORTHERN HEMISPHERE. CONSERVATION OF ANGULAR MOMENTUM. *THANK YOU* I've been ripping my hair out for the last hour trying to figure out why why WHY because it just makes sense for an object travelling North from the equator to deflect 'left'.
Yes. It can be a tricky concept to wrap your head around, but this video lays it out very clearly. Despite what other commenters say, objects deflect RIGHT in the northern hemisphere!
How can you say that the Coriolis-effect is least on the equator and largest at the pooles? My suggest is: If I place a ball in the middle of the rotating board (or at the North /south pole) it will not move at all! Right or wrong?
So if I understand correctly. The earth is rotating to the east. If you move an object to the north from the equator the object is getting closer to the axis of rotation, therefore because of preservation of angular momentum the velocity must increase, thus the velocity to the east (if moving the object to the north) is increased. Just as an ice dancer will rotate faster if he or she puts his or her arms tighter to the body. If you travel east or west, you are actually increasing vs decreasing your rotation, so thtat wil cause the obejct south if going east and north if going west, because going away from the axis of rotation means a force to the south.
Its because your moving as the air moves . take for Example your wind speed is 0. But it is actually moving , just that you are moving at the same speed as the air at apparent 0 is. However , when the air picks up speed(known as wind) , it has a resultant velocity higher than you(your standing still) , then you have winds. SO if the earth rotates at xkm/h , you move at xkm/h , and the 'still' air is moving at xkm/h
One thing I don't get... The rotational velocity of the air DECREASES as it moves north as demonstrated at 0:36, however according to the conservation of angular momentum, since the "radius" of the rotation (I can't word it better) is decreasing, shouldn't the rotational velocity be INCREASING? I'm confused...
I'm looking for the word or term that describes a phenomenon. If a person was driving in a car at a reasonably fast speed, and that person were to look out the window, that person would see objects close by whizzing by very fast, but objects in the distance moving very slowly. What is this called?
If you're having difficult to understand how it works as I, just look for which direction in the scenery the ball is going and see how it doesn't change what moves out is just the merry go round. Think like that: The ball is moving toward some tree in the scenery when the "boy 1" throws it to the "boy 2", the direction point of the ball will still be the tree and the movement curvature is caused because boy 1 back is going to reach the same point as the ball was thrown. To understand what I'm saying, try to analyze by yourself first.
If we are moving 1000+mph east, why is the speed of sound the same in both directions and there no apparent doppler effect while standing still on earth and yelling in one direction opposed to another. Because the the air is also moving around 1000+mph east and that is the medium in which sound travels? What about light. Is light moving faster away from us if we shoot a laser to west than if we shoot it to the east???
Shouldn't you have used Tangential Velocity when talking about how it decreases with travelling to greater latitudes on earth? Since Rotational Velocity - a.k.a. Angular Velocity - is a displacement that is in direct proportion with the angle covered by the radius of the motion. However short the radius may be, the angle is still the same. What decreases proportionally with the radius from the rotational axis is Tangential Velocity. Correct me if I'm wrong.
if the CF causes objects to deflect to the 'RIGHT' of their intended path in the NH, should hurricane and cyclones circulate 'CW' in the NH? why they circulate 'CCW' in the NH? i'm confused :(
At 5:34 he says that the Coriolis force is zero at the equator and maximum at the poles. Since there is no angular momentum at the poles and maximum at the equator, doesn't he have this backwards? Isn't the Coriolis force zero at the poles and maximum at the equator?
Quite a logical assumption to make, but false nonetheless. On the actual equator, the rotational forces of the Southern and Northern Hemisphere cancel out. As you deviate from the equator, one force will 'lessen' and the other will 'strengthen', resulting in net rotational direction, depending on the hemisphere.
The answer is found by looking at the shape of the earth. Near the equator, if you travel 100 km closer to either of the poles, you've barely gotten any closer to the axis of rotation because the earth's surface at the equator is parallel to the axis. But if you are 100 km away from the north pole and you head towards the pole, almost all of your distance is going towards the axis of rotation, because at the poles, the earth’s surface is perpendicular to the axis.
You cannot understand this unless you watch 4 5 videos on it. We have to study the direction of wind from all 4 cases. 2 for northern hemisphere and 2 for southern Case 1: high pressure area above low pressure - then movement is down and left from observers pt. of view. Case 2: low pressure above high pressure- movement up and right For Southern Hemisphere Case 3: low pressure above high pressure - movement up and to left Case 4 : high pressure above low - movement down and right Case 4
True, or just watch a "map" that shows this. The most common mistake is to think that the vind will bend the other way, since the earth has moved beneath it. But the fact is that the wind itself is moving at 1600 km/h at eq, so it will travel a shorter distance when moving north.
Emisphere and right in the Northern Hemisphere. If the object we are considering is moving from the poles to the equator, it will meet points with an higher angular velocity than its, so it will be late compared to these points. If you try to draw the earth and the trajectories, you will notice that they will alway go left in the SH e right in the NH because of what we have previously said. That's the reason i think. I apologyze for my bad english.
Hurricanes go counterclockwise, BECAUSE any object in motion is defected to the right! Sounds couterintuitive doesnt it? If there is a low pressure area, all air molecoles move toward it, all veering right. Draw a picture of this situation and think about it. It is very easy to see that it would set up a ccw rotation
Hello I know I am missing something and I have to ask... the video at 4.26 shows the air going clockwise. I am a bit muddled the video then explains low pressure air in the Northern Hemisphere moves counter clockwise, so why does low pressure move counter clock wise when CF would make things deflect to the right in the Northern Hem?
@PotatoeSmiley It's an effect, it's not a force, it's only a perceived deflection when viewed from a rotating/non-inertial reference frame, so you can't attribute any actual effects due to the Coriolis Effect, on any storms! Welcome to Flat Earth!
+James Dean I would suggest that the rotational "effect" imparted on a tennis ball is due to the different resistance of the air against the spinning ball surface.
If the toilet bowl was perfectly smooth it would. The imperfections in the toilet bowl influence the direction of the rotation. This is unlike a system so large that the imperfections aren't significant enough i.e. a hurricane, the Coriolis Effect is present
Thank you, a very good and relatively easy to understand video, with good practical examples and nice conclusion/definition at the end. Keep up the good vids! :)
The video is very clear except that the narrator repeatedly says that the rotational velocity decreases with higher latitudes. The rotational velocity of the earth applies to the earth as a whole and is the same at all latitudes. It is the TANGENTIAL velocity of the surface that decreases with latitude.
"Rotational velocity" has a somewhat ambiguous understanding. The narrator is using it to mean tangential. The preferred term for angle/time is "angular velocity."
Cyclones flow counterclockwise in the NH because there are other forcings to their movement than just conservation of angular momentum like deformations of the atmosphere mass field which create pressure gradients. Yet you can notice that tropical cyclones follow clockwise paths during their lifetime. Imagine the ball being twisted to spin around its axis before being thrown across the carousel. It would still be defleted anti-cyclonically, but would also spin around its axis.
Hmmm, I still don't see how the CF is zero at the equator.. where the Earth's rotational velocity is at its greatest. I mean, the trade winds are deflected more and more to the right (in the Northern Hem) as they approach the equator..? Perhaps latitudinally, but not longitudinally...
![Felix "Unfair" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/Oswujxm2Ag0/mqdefault.jpg)
Thank you!!! FINALLY - somebody actually explains conservation of angular momentum in a clear and concise fashion. Excellent video.
@bigboam
Haha, they may have mentioned conservation of angular momentum, but it has nothing at all to do with the Coriolis Effect!
Its only a perveived deflection when viewed from a rotating/non-inertial reference frame, nothing at all to do with conserving of angular momentum.
What you need to do is research Flat Earth, as we never see a plane deviating due to the Coriolis Effect, because the Earth is flat and stationary!
The merry-go-round demontrations were very good!
Searched about 5 other videos about this effect but this is the best one yet, Gonna get a A on the test tomorrow :)
@@ChattingAroundTheWorld that was 9 years ago. I think I got an A though...
Definitely the best video which was successful to explain it the correct way. No video till now mentioned conservation of angular momentum.
Pressure gradient (and friction as well) are also playing a role in the direction of winds within a hurricane. Coriolis is only one factor. Winds "want" to move directly to the center of the hurricane (directly towards low pressure - aka its pressure gradient). However, the Coriolis deflects the path of the winds to the right a bit, not allowing the winds to go directly towards the low. This results in counterclockwise flow around the low pressure center. Hope that helps!
Roger, good question! my background is in meteorology with advanced research in severe weather (tornados, hurricanes). to really get an understanding on an answer relating to your question would take too long for this 500 char. window here. it's a complicated answer that involves more than just the 'coriolis force' - it also involves other forces all acting together at the same time (magnus and rossby forces, reynolds numbers, fluid dynamics, temp.& pressure, topography)- more than newton's laws
Terrific presentation. Five stars.
Lmfaooooooo u can’t give stars in a RUclips video 💀
storm winds are the resultant of the gradient force caused due to pressure difference and the coriolis force. thus if you look at the centre of storm (direction of gradient force) and imagine that coriolis force acts to your right hand the resultant motion would be counterclockwise in direction
brilliant explanation, thank you
thanks for making my life even more confusing
🙌🥴
awesome video, very comprehensive, thanks
@lEtudel This is difficult to explain w/o visual aids, but I'll try anyway. In a low pressure system, air is coming in from everywhere around the system. On a sheet of paper, draw a circle with an L in the center to represent the storm. Now, draw arrows all around the circle pointing to the L. For the NH, the CF is to the right, so on the arrows you just drew, draw more arrows pointing to the right of the direction each original arrow is traveling. You'll notice this causes a CCW spin.
After 2:48m the video stops. The audio continues normally and the individual frames can be seen if you hover over the video, but the last *moving* image seen is the first line of the angular momentum explanation.
This happens in both Opera V12 and Firefox V21. (July 2013)
Great video, I use it a lot in my college geography class. Only one problem - rotational velocity at any point on Earth's surface (angular displacement per unit time). The narrator often confuses rotational velocity with linear velocity, which does vary from latitude to latitude.
When moving from equator to one of the poles, objects get a higher rotation frequency than that of the earth, so they get deflected in the same direction as earth’s rotation, which is to the east. For objects moving from equator to the North Pole the east is to the right, for objects moving from equator to the South Pole the east is to the left.
@shootingnerd
shooting, it's a good question, and although you get the same type of effect, the underlying physics is much different than described in this video for zonal (east-west) movement. It's because a westward moving object is moving slower than the Earth, and an eastward moving object faster than the Earth. Ultimately, you adjust latitude by allowing the centripital acceleration to be sufficient to balance the gravitational force
That would send them further off path. The counter clockwise motion literally counteracts the effects of Coriolus. Offsets it so the low pressure system would stay on track or not drift.
Very well explained, Thank you
This Video is extremely detailed , before even done , was well studied . A lot of effort was definitely put here to teach us , thank you :)
Nicely explained. Thanks! Would be good if you could elaborate on hurricanes though, e.g everything in the northern hemisphere deflects to the right, but the hurricanes cyclonic circulation is anti-clockwise. How does the right deflection invoke an opposite spin direction for wind??
Friction between the air and the ground. The part further south gets dragged along faster with the ground, so the rotation is counter clockwise. That's my guess.
Because, as the video explains, the 'Conservation of Angular Momentum' means that the parcel of air tries to maintain its angular momentum and moving north or south in the Northern Hemisphere, the air parcel will try to steer itself in a right-handed direction.
Amazingly explained... very good example used
great video sir...
you explaind very well...
Beautifully explained
In consider yourself moving away from the equator. If you go south, away form the equator on the southern hemisphere, the direction you need to move to keep a same angular momentum is the direction of the earths movement, so to the left. If you travel north away from the equator, on the northern hemisphere, you still need to move towards the direction of the earths rotation, so to the right.
Very elegantly explained with wonderful, simple demonstrations. Nice work, and thanks.
great explanation ! thank you So much!
Put very simply, it is that an object in motion tends to move in a straight line. The earth is turning underneith the moving objevct. Vizualize a cannon sitting on th north pole, firing at a target 20 mi away. Lets say the shell takes 30 seconds to reach the target. Th earth is turning counterclockwise--at a rate of 7.6 feet/sec. Where does the shell land?
Wow what a great video. thank you
When the object moves East, there is no change in radius (you stay at the same latitude). As the mass is constant, the conservation of angular momentum suggests that the velocity remains constant. So why does the corriolis 'force' continue to deflect the object to the right, towards the South (on the Northern hemisphere) ?
Imagine a world where videos like this had 1,900,000,000 views and 'Gangnam style' had 280,000....
question though:
Is air moving downward from the north pole because downward is outward in this case (thinking centrifugal force)?
And when it creates a cyclone pattern does it move to the right initially as it it move south and left as it circulates northerly again for that reason, that it is circulating north in that hemisphere of the cyclone pattern.... as it would if it were in within an anti cyclone in the southern hemisphere?
Finally! A clear explanation. The angular momentum explanation makes sense. And the merry-go-round illustrations are wonderfully clear. Thank you.
What about just mentioning inertia? More visible explanation
They say that a mass following any latitude (other than the equator) eastward coriolis-e. will turn it to north, in norhern hemisfere. If so, the coriolis-effekt is not caused by the different surface-velocity on earth. (Which is the normal explanation of the coriolis-effect) They say also that the coriolis-effect is less (0) on the equator and maximum om the poles! But if you place a ball on the pole and turn the sphere(or board) as fast as possible the ball will stay on the pole. Explained?
Great video .. thanks
Nice video, but for me leaves more questions than answers, for example:
1. The merry-go-round demonstration contradicts the physical explanation regarding conservation of angular momentum. The reason the baseball circles is simply because it is following a straight line relative to the ground. If your frame of reference is rotating, then in that frame of reference the straight line is a circle. This has nothing to do with conservation of angular momentum: the ball is just traveling along a straight line at constant linear velocity.
2. "The Coriolis force increases with speed of the object" This would seem to imply that the deflection in the movement is greater when the speed increases. But obviously, this is not true on the merry-go-round. If you shot a bullet across the merry-go-round, there would be practically no deflection at all. The deflection would increase with the speed of the rotation, not the speed of the object. If the speed of the projectile is very high relative to the speed of rotation, then it seems we could practically ignore the rotation and there would be no Coriolis force.
This leaves me with the impression that the merry-go-round demo has nothing to do with the Coriolis force. Can somebody explain?
Bill Ravenwood no. These are the precise questions flat earthers ask, in which nobody provides an answer to. There is no answer to your question if our globe is the correct model of our planet- it is impossible.
Well, you managed to greatly misunderstand and misinterpret what the video was all about. Having said that I admit some points made in the video are terribly presented so as to confuse rather than clear up any confusion.
1. The baseball doesn't follow a straight line relative to the ground. It would if it didn't make contact with the surface of the marry-go-round (i.e if it was thrown). Even if it's just placed on top, it would still make a circle relative to the ground. The real trajectory of the ball in the video relative to the ground is a semicircle.
However there is some sense in saying "this has nothing to do with the conservation of the angular momentum" as the ball, being in contact with the surface, is actually moving in the opposite direction of rotation because of inertia. Just like standing passengers in bus that lurches forward fall in the opposite direction of the movement of the bus.
2. Truthfully I had hard time understanding the logic behind that sentence too. It just makes no sense until you think about the path travelled (greater speed = longer distance= moving closer to the axis=greater deflection). It has nothing to do with speed really so the author is wrong. It's all about the path. Even if the object is travelling slowly, if it covers more ground ultimately it would still amount to greater deflection.
If you shot a bullet across the merry-go-round then the deflection would be minute but that's because the bullet isn't part of the same frame of reference.
Bill Ravenwood 1) Your reasoning is fine, aka curved space-time in general relativity. Another is coriolis force in classical mechanics. It's fictitious, appears to exist in rotating ref frames (and for newtons laws to work). Vid relies on angular momentum at points where its irrelevant. 2) You need to sit near the centre of a merrygoround and fire the gun; bullet appears to take a wicked deflection. For outside observers, bullet and ball take straight paths. Merrygoround's angular velocity (rate it completes full turns) affects the force, as does object's velocity.
Yes, Bill, you are absolutely correct! The merry-go-round is simply a demonstration of Newton's first law of motion that happens to look like Coriolis force at work. The confusion happens when people like you are smart enough to figure out that in both cases illustrated in the video, the ball is actually just going in a straight line through space, which you can easily see from the bird's eye view. In one case it flies in a straight line and in the other it just rolls in a (relatively) straight line. (The apparent motion of the ball as viewed from a seated position on the rotating merry-go-round would be identical if the ball were thrown over the center of the ride by a distant observer.) So this is not an experiment showing actual Coriolis force being applied. The reason for this is that as soon as the ball is released, the centripetal force disappears and it's momentum becomes linear. Yes, there was angular momentum but that was preserved by this transformation. The explanation of that is a little abstract, so just accept that the ball is no longer part of the rotating merry-go-round system; it's simply a free body moving through space with an angular velocity relative to the center of the merry-go-round. Trouble is, while it is related to angular momentum, angular velocity is not a conserved quantity - so there will be no Coriolis force applied with respect to the rotation of the carousel. On the other hand, if you can overlook the fact that you are not observing actual Coriolis at work, it's still a pretty good demonstration of the effects of Coriolis, because the behavior of the ball is the same as if you were observing real Coriolis. The only difference is that instead of applying an actual force to the ball to physically curve its motion through the rotating reference, the merry-go-round is simply moved underneath relative to an object moving in accordance to Newton's laws. In other words, the apparent path of the ball in the experiment follows an actual path that would happen in an actual rotating system.
But I get your frustration, because using a visual trick to illustrate the effect of Coriolis makes many people, even some fairly knowledgeable on the subject, believe that Coriolis is only an apparent force. Unfortunately, it is nearly impossible to observe actual Coriolis on such a small scale. I can assure you that Coriolis is very real - it's just not being observed in this example*. If it weren't real, there would be no force to oppose an atmospheric pressure gradient force, and since F = MA the mass of air would accelerate and move directly from high to low, equalizing the pressure difference almost immediately. Since it does not accelerate in this manner, there must logically be some force acting in opposition to it, and that is indeed Coriolis. Acceleration still occurs, but not as a result of a change in speed; the acceleration is due to a change in direction, as the force is applied at a 90 degree angle to the initial movement of the air mass. So no energy is added or removed from the mass; it is only driven off the direct line from high to low pressure.
This applied force increases steadily as the air mass moves poleward. This is because as it does so the mass is getting physically closer to the axis of Earth rotation. You can see clearly that in this case the air mass is not anything like the ball in the video because it is rotating with the Earth as it tries to accelerate from high to low. Therefore it is part of the rotating system and as poleward advection occurs, the angular momentum of the air is conserved as in the example of the ball on a string accelerating as the string gets shorter and this increase in speed is instantaneously met with increasing Coriolis force to change the direction and maintain a constant momentum, which is Mass x Velocity, or p = mv. So it could be said that Coriolis force is just a term for Conservation of Angular Momentum as realized in a rotating spherical reference.
* Notice I said it isn't OBSERVED. I didn't say it isn't AFFECTED. The ball actually is affected by Coriolis with respect to it's angular momentum referenced to the Earth. It is not affected at all by its motion referenced to the merry-go-round. But you can't observe the effect of Coriolis on the ball because it is so infinitesimally small as to be nearly immeasurable. Thus, the parlor trick has to be employed to illustrate on a small scale what actually happens in full scale. Taking this explanation a step further, it would still work in the southern hemisphere, where actual Coriolis force would act to the left. But on a merry-go-round moving counter-clockwise in Australia, the ball would still appear to move dramatically to the right with respect to the carousel, even though it is actually moving an un-observably small amount to the left with respect to the correct and actual Earth reference. In other words, everything I'm saying here can be proven simply by duplicating the video experiment anywhere in the southern hemisphere. Or, albeit probably less convincingly, by instead turning the carousel clockwise any where in the northern hemisphere and observing an impossible-to-achieve-by-Coriolis left apparent deflection while the actual deflection would be very slightly to the right.
You're correct that the parcel on earth will go in a circle ignoring centrifugal force because of the oblateness of the earth. That's not true about the merry go round. On it, the ball does not go in a perfect circle in the frame of reference of the marry go round because of centrifugal force.
I'm not a physiscist or whatever, but i think it's becuase every object tends to maintain it's linear velocity (angular velocity[costant] x radius[distance from rotation axis]). So, if an objects moves from the equator to one of the poles, the points located in the imaginary line it covers will have a linear velocity wich is inferior to the one of the object we are considering, so the object will Always anticipate those points. If you consider the trajectory this go left in the Southern...
Amazing analogy
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And in answer to gafodde, no, because for the Coriolis effect to come into play, the parcel has to cross to the other hemisphere for it to curve the other way. Therefore, it will stay on that hemisphere, as the parcel cannot be in two hemispheres at once. Also, if you made sure that it was exactly at the equator, there is no Coriolis force at the equator. Hope that answered your question :)
Nicely explained
can someone help explain at the southern hemisphere why the winds deflect left? i can understand at northern hemisphere , where the velocity is higher , and hence , pushes the wind movements to the right. But if the earth rotated rightward , why is it that at the southern hemisphere , the winds deflect left????? I really need help on this .
THIS IS THE ONLY VIDEO THAT ANSWERS *WHY* THE THING GOES RIGHT IN THE NORTHERN HEMISPHERE.
CONSERVATION OF ANGULAR MOMENTUM. *THANK YOU*
I've been ripping my hair out for the last hour trying to figure out why why WHY because it just makes sense for an object travelling North from the equator to deflect 'left'.
Yes. It can be a tricky concept to wrap your head around, but this video lays it out very clearly. Despite what other commenters say, objects deflect RIGHT in the northern hemisphere!
I understand why the parcel deflects to the right.. but why does it come around full circle?
Thanks! This was very helpful!
this videos is excellent!
Excellent!
How can you say that the Coriolis-effect is least on the equator and largest at the pooles? My suggest is: If I place a ball in the middle of the rotating board (or at the North /south pole) it will not move at all! Right or wrong?
So if I understand correctly. The earth is rotating to the east. If you move an object to the north from the equator the object is getting closer to the axis of rotation, therefore because of preservation of angular momentum the velocity must increase, thus the velocity to the east (if moving the object to the north) is increased. Just as an ice dancer will rotate faster if he or she puts his or her arms tighter to the body. If you travel east or west, you are actually increasing vs decreasing your rotation, so thtat wil cause the obejct south if going east and north if going west, because going away from the axis of rotation means a force to the south.
That's right. Doesn't apply to earth though. It only applies to rotating bodies. Earth isn't rotating.
@@sleepingwarrior4618 : LOL. I see that good old Wavex did fall for your shenanigans, Anthony.
But what about inertia? Wouldn't the ball move straight in the frame of reference which is the merry-go-round? I'm confused.
Thanks! This is splendid.
Its because your moving as the air moves . take for Example your wind speed is 0. But it is actually moving , just that you are moving at the same speed as the air at apparent 0 is. However , when the air picks up speed(known as wind) , it has a resultant velocity higher than you(your standing still) , then you have winds. SO if the earth rotates at xkm/h , you move at xkm/h , and the 'still' air is moving at xkm/h
One thing I don't get...
The rotational velocity of the air DECREASES as it moves north as demonstrated at 0:36, however according to the conservation of angular momentum, since the "radius" of the rotation (I can't word it better) is decreasing, shouldn't the rotational velocity be INCREASING? I'm confused...
I'm looking for the word or term that describes a phenomenon. If a person was driving in a car at a reasonably fast speed, and that person were to look out the window, that person would see objects close by whizzing by very fast, but objects in the distance moving very slowly. What is this called?
Thanks! Interesting and helpful. It can be a confusing concept but this simplifies it.
what if you threw the parcel of air from the northern hemisphere, over the equator, to the southern hemisphere? would you get a figure of 8?
How come the hurricanes are deflected to the left on NH then??? Can someone explain please?
Kindly tell me the reason why corriolis is zero at equator.
If you're having difficult to understand how it works as I, just look for which direction in the scenery the ball is going and see how it doesn't change what moves out is just the merry go round.
Think like that: The ball is moving toward some tree in the scenery when the "boy 1" throws it to the "boy 2", the direction point of the ball will still be the tree and the movement curvature is caused because boy 1 back is going to reach the same point as the ball was thrown. To understand what I'm saying, try to analyze by yourself first.
1:08 This might be a stupid question, but her it goes: Wouldn't a person weigh less at the equator than at the North or South poles?
Elisa Bell yes!!
If we are moving 1000+mph east, why is the speed of sound the same in both directions and there no apparent doppler effect while standing still on earth and yelling in one direction opposed to another. Because the the air is also moving around 1000+mph east and that is the medium in which sound travels? What about light. Is light moving faster away from us if we shoot a laser to west than if we shoot it to the east???
Why the vector of the north is vice-versa with the south ?
Shouldn't you have used Tangential Velocity when talking about how it decreases with travelling to greater latitudes on earth? Since Rotational Velocity - a.k.a. Angular Velocity - is a displacement that is in direct proportion with the angle covered by the radius of the motion. However short the radius may be, the angle is still the same. What decreases proportionally with the radius from the rotational axis is Tangential Velocity. Correct me if I'm wrong.
Excellent explanation! The baseball loop is particularly good, thanks!
this video helped me alot with my science homework
thanks
if the CF causes objects to deflect to the 'RIGHT' of their intended path in the NH, should hurricane and cyclones circulate 'CW' in the NH? why they circulate 'CCW' in the NH? i'm confused :(
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Anticlockwise
@cmc0605
so ,eg., For eastward movement, the centrifugal force is increased and the body is deflected toward the equator, to the right of the movement
At 5:34 he says that the Coriolis force is zero at the equator and maximum at the poles. Since there is no angular momentum at the poles and maximum at the equator, doesn't he have this backwards? Isn't the Coriolis force zero at the poles and maximum at the equator?
Quite a logical assumption to make, but false nonetheless. On the actual equator, the rotational forces of the Southern and Northern Hemisphere cancel out. As you deviate from the equator, one force will 'lessen' and the other will 'strengthen', resulting in net rotational direction, depending on the hemisphere.
The answer is found by looking at the shape of the earth. Near the equator, if you travel 100 km closer to either of the poles, you've barely gotten any closer to the axis of rotation because the earth's surface at the equator is parallel to the axis. But if you are 100 km away from the north pole and you head towards the pole, almost all of your distance is going towards the axis of rotation, because at the poles, the earth’s surface is perpendicular to the axis.
sir please tell me why coriolis force high at pole and zero at equator
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Spin on an office chair with your arms out, now tuck them in and watch your speed increase, same effect
Can the Coriolis Force be used to produce Energy?
You cannot understand this unless you watch 4 5 videos on it.
We have to study the direction of wind from all 4 cases. 2 for northern hemisphere and 2 for southern
Case 1: high pressure area above low pressure - then movement is down and left from observers pt. of view.
Case 2: low pressure above high pressure- movement up and right
For Southern Hemisphere
Case 3: low pressure above high pressure - movement up and to left
Case 4 : high pressure above low - movement down and right
Case 4
True, or just watch a "map" that shows this. The most common mistake is to think that the vind will bend the other way, since the earth has moved beneath it. But the fact is that the wind itself is moving at 1600 km/h at eq, so it will travel a shorter distance when moving north.
so does this mean that water drains clockwise in one hemisphere and counter-clockwise in the other?
why it is zero at equator and max at poles?
great video
Best explaination thank you.
I need to now why the effect of coriolis on wind is different in different hemispheres though the earth rotate east to west on both hemispheres?
Emisphere and right in the Northern Hemisphere. If the object we are considering is moving from the poles to the equator, it will meet points with an higher angular velocity than its, so it will be late compared to these points. If you try to draw the earth and the trajectories, you will notice that they will alway go left in the SH e right in the NH because of what we have previously said. That's the reason i think. I apologyze for my bad english.
Hurricanes go counterclockwise, BECAUSE any object in motion is defected to the right! Sounds couterintuitive doesnt it?
If there is a low pressure area, all air molecoles move toward it, all veering right. Draw a picture of this situation and think about it. It is very easy to see that it would set up a ccw rotation
yes but the speed of light is 300 million metres per second, and the coriolis effect is negligible in this case.
Hello I know I am missing something and I have to ask... the video at 4.26 shows the air going clockwise.
I am a bit muddled the video then explains low pressure air in the Northern Hemisphere moves counter clockwise, so why does low pressure move counter clock wise when CF would make things deflect to the right in the Northern Hem?
This video helped me understand this a bit: ruclips.net/video/rVrNXBioPG4/видео.html
@PotatoeSmiley
It's an effect, it's not a force, it's only a perceived deflection when viewed from a rotating/non-inertial reference frame, so you can't attribute any actual effects due to the Coriolis Effect, on any storms!
Welcome to Flat Earth!
If you span fast enough, could you catch the ball you throw?
The best video i ever see
Wow this is great! You guys should do more teaching videos.
A really good video , really helped my understanding....
So how does the conservation of angular momentum translate into a tennis ball not increasing in speed but rather circling to the right?
+James Dean I would suggest that the rotational "effect" imparted on a tennis ball is due to the different resistance of the air against the spinning ball surface.
Nice video. My english is bad and I understand you only half things, but you still teach me more then my teacher and Wiki :)
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If the toilet bowl was perfectly smooth it would. The imperfections in the toilet bowl influence the direction of the rotation. This is unlike a system so large that the imperfections aren't significant enough i.e. a hurricane, the Coriolis Effect is present
is it an enclosed system or is it not it?????
Thank you, a very good and relatively easy to understand video, with good practical examples and nice conclusion/definition at the end. Keep up the good vids! :)
The video is very clear except that the narrator repeatedly says that the rotational velocity decreases with higher latitudes. The rotational velocity of the earth applies to the earth as a whole and is the same at all latitudes. It is the TANGENTIAL velocity of the surface that decreases with latitude.
"Rotational velocity" has a somewhat ambiguous understanding. The narrator is using it to mean tangential. The preferred term for angle/time is "angular velocity."
Thanks for clarifying that.
i can only say THANK YOU
Cyclones flow counterclockwise in the NH because there are other forcings to their movement than just conservation of angular momentum like deformations of the atmosphere mass field which create pressure gradients. Yet you can notice that tropical cyclones follow clockwise paths during their lifetime. Imagine the ball being twisted to spin around its axis before being thrown across the carousel. It would still be defleted anti-cyclonically, but would also spin around its axis.
Hmmm, I still don't see how the CF is zero at the equator.. where the Earth's rotational velocity is at its greatest. I mean, the trade winds are deflected more and more to the right (in the Northern Hem) as they approach the equator..?
Perhaps latitudinally, but not longitudinally...
Why can you use SI? In the world of science we use meter, or metre, not miles...
In Ireland most of our weather systems seem to come from the west, that is weird seeing as we are rotating to the east.
So the air starts flowing faster when it moves towards higher latitudes? Why is it called rotational velocity and not just wind speed?
But this doesn't explain why the coriolis effect also works on objects/air that is moving in an east-west direction.