Good video on coriolis. Only complaint is the section mentioning cyclonic storms.
With regards to tornado rotation direction:
What causes tornado formation is the crossing of two air currents. This crossing causes wind shear, which gets air rotating into a horizontal tube. This rotating tube then gets pulled vertical by convective updraft, which is what generates the funnel cloud. See formation here.
It makes every sense in the World, whereas clockwise doesn’t. On the Northern hemisphere the Sun moves across the sky from left to right and on the Southern hemisphere from right to left. This is an absolute movement relative to the equator. Clockwise and counter-clockwise are arbitrary terms based on a convention to make the clock-hands move in a certain direction.
Just take a look at this clock. Would you say that the hands move clockwise or counter-clockwise? Sunwise or counter-sunwise?
On second thought I think I should add that both clockwise and sunwise have their uses that sometimes overlap and sometimes don’t. It all depends on context.
The first thing that occurred to me was what the OP posited - things going left to right are ‘forward’ and things running right to left are ‘backward.’
However, even if that relationship is ‘real,’ the question remains which is the cause and which is the effect. Do most races go left-to-right because left-to-right is the forward direction for number lines, most writing systems, comic strips, and so forth, or do most writing systems, number lines, comic strips, and so forth go left-to-right because most races do?
Writing is less smudgy if you’re right-handed, writing with a dip pen, going left to right. Other than that, I don’t know.
Quite a few auto races on “road courses” are clockwise (not just Formula 1), aren’t they? The NASCAR race at Sears Point - er, Sonoma is run clockwise.
OTOH, I’m pretty sure most horse races in England are run clockwise. (One notable exception seems to be the Grand National.)
I have heard one story that things created in the USA are run counterclockwise “just to be different from the way England does it”. One thing this doesn’t explain, however, is track and field - I am under the impression that they ran counterclockwise on the track at the 1896 Olympics in Athens.
The sun moves from east to west. If you are looking north, it does not matter which hemisphere you are in, the sun tracks from right to left. If you are looking south, the sun tracks from left to right.
Now if you are looking at the shadows caused by the sun, then that defines which direction you look, so you look north in the northern hemisphere and south in the southern hemisphere. But like I said, that gets convoluted. It’s not “sunwise” but maybe “shadowise” or “sundialwise”.
Yes, the convention derived from the sundial in the northern hemisphere, where clocks originated. Sure, it’s arbitrary in that either would have worked, but it’s a convention and it was based on something specific when derived.
A backwards clock. Whoopee. Yes, the hands move “counterclockwise”. It’s just a goofy clock. I certainly wouldn’t connect “sunwise” or “counter-sunwise” to that.
Now if you really want to complain, argue that most clocks are digital now, so the connection between “clockwise” and rotation makes less and less sense to younger generations. Someday children will have to have explained that there used to be these things called analog or dial clocks, with rotating hands that showed you the time. And they’ll be all confused - why would anyone think that makes sense, when they could have just used a digital clock.
Uh…what?
Firstly, it is indeed a relative movement, not absolute, unless you reject Copernican theory.
Secondly, “relative to the equator?” It (apparently) crosses the equator moving north and south as the earth goes around the sun, but the sun’s apparent path is a ring around the equator, which is also a ring (although tilted). Even with an “up” or “down” reference point, which we lack, I’d be hard pressed to describe that as “moving left to right.”
Nope. It depends on latitude and the day of the year. It goes one way all year only outside the tropics.
Reading more closely, you apparently define the equator as the expected way to face before looking at which way the sun moves. This is just as arbitrary as any other method to determine “clockwise” and “counterclockwise”. At least the conventional method has roots in history.
[QUOTE=Sailboat]
Firstly, it is indeed a relative movement, not absolute, unless you reject Copernican theory.
[/QUOTE]
I think you are unnecessarily getting caught up in terminology. I don’t think Floater is trying to discount the concept of relative motion, rather, he is trying to state that if you use the equator as your reference point (and the equator is a physical property of the Earth), then the rotation directions are consistently defined from there. Anywhere in the Southern hemisphere looking at the equator, one is looking north, and vice versa for the Northern hemisphere. Ergo, you get consistent Sun paths across the sky. Except he overlooks that the choice to use the equator is arbitrary.
[QUOTE=John W. Kennedy]
Nope. It depends on latitude and the day of the year. It goes one way all year only outside the tropics.
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Took me a minute to catch your point. While the Sun’s path varies more northerly or southerly based upon the season and location, the general path is always East to West. That is, I believe, all Floater was claiming. I don’t think he’s talking about crossing the equator, he’s talking about facing the equator to determine if East is right or left.
For every math equation I post, the joke will be half as funny. I’m pleased Irishman got it, “You’re apparently then trying to say that 30º rotation means that the car gets a 30º boost.” The track itself rotates 30º in 2 hours when viewed from a place where the fixed stars are stationary, thus carrying along anything placed on the track, or in the grandstands. C’mon, that’s at least as funny as drivers being right-footed.
[QUOTE=watchwolf49]
For every math equation I post, the joke will be half as funny.
[/QUOTE]
That was a joke?
I’ll give you that.
Of the 58 racecourses in GB, 23 are clockwise and 35 are anti-clockwise. But it’s more complicated than that.
Fontwell stages hurdle races anti-clockwise round the outside of the track and steeplechases on the figure-of-eight course in the centre. The racing at Windsor also takes place round a figure-of-eight. As for the races themselves most racecourses have a configuration allowing sprint races to be run over a straight section of the track. In fact some courses, for example Ascot, allow races up to 1m to be run over a straight course.
But only with teeny tiny horses.
It’s not arbitrary; if you’re south of the Tropic of Capricorn and tracking the motion of the sun, you’re not going to be looking south; you’ll be looking north, and thus seeing the sun move right-to-left.
That said, I also had no concept of what “sunwise” or “counter-sunwise” means. “Right-to-left” or “left-to-right” are poor ways to describe rotation, as they’re ambiguous.
Powers &8^]
What if you face south and then lean over backwards? 
Okay, fair point.
The problem is that “right” and “left” are subjective notations - they depend on and refer to the observations of the person making the observation, based upon his location and orientation. They are not absolute references that can be applied from any observer in any position. What is right to me is left to you, what is right to me facing one way is left to me facing another way. What is right to me becomes left if I stand on my head. You have to know my exact position and orientation before those words are meaningful.
My siblings and I once came up with a game* for giving directions driving a car. It’s the “this way/that way” system. I’m in the passenger seat giving you, the driver, directions on where to turn. “Turn this way in 50 ft.” You reply “Turn that way in 50 ft”, because for you, “this way” would be left and “that way” right, but for me, “this way” is right and “that way” is left. It’s the same thing. “This/that” refer to which side of the car one is on.
It’s also why boats use “starboard” and “port” rather than “right/left”. It makes it clear you mean the boat’s right/left rather than the speaker’s.
- It was amusing for a few minutes.
That’s a problem, yes, but I’m not sure it’s the problem in question. The problem I was referring to was describing a rotation as “left-to-right” or “right-to-left” when, at any given time, part of the rotating object is moving rightward and part is moving left (unless, of course, the axis of rotation is parallel to the observer’s eye line, in which case the rotating object is moving neither right nor left).
But even “clockwise” and “counter-clockwise” depend on assuming the observer is on one particular side of the rotating object. In an earthly frame of reference, of course, we usually assume we’re looking down toward the center of the earth. Regardless, though, my point stands that “sunwise” is neither transparent enough nor unambiguous enough to be useful.
Powers &8^]
This is also why theatre people speak of “stage right” (occasionally “house left”) and “stage left” (occasionally “house right”), as well as “upstage” and “downstage”. (In the UK, “prompt[er] side” and “opposite prompt” are traditional.) Similarly, heralds use “dexter” and “sinister”, meaning the right and left of the imaginary knight carrying the shield before him and facing the onlooker.
If you’re looking at a sweeping arm (like a clock), then that makes sense. However, if looking at the path traced by, say, the head of the arm, then it does make sense.
Think of what a “right turn” means - the path moves rightward from the original path. Now look at the path traced by the clock arm end - it rotates rightward from the previous path. At the twelve position, the end starts moving down. At the 3 position it is moving down and starts to move to the observer’s left. Those are right turns for the end of the arm.
Now when talking about stationary swirls, like a nautilus, is the curl inward or outward? But if there’s motion (or implied motion), then a right curve or left curve is sensible, and that can match clockwise and counterclockwise.
Agreed, as that was part of my original point.
All of this is because we live on the south side of the universe, on the north side of the universe everything spins clockwise.