# Dexterity

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 28615.  Fri Oct 28, 2005 2:24 am This thread is giving me a mild case of déjà vu - didn't we bounce the subject of handedness around before, from a starting-point which had to do with the directions of snail-shell spirals? I'll see what a Search will bring up.

 28620.  Fri Oct 28, 2005 3:20 am Flash The way i got this right in my own mind is this. Given that the definition of left and right is arbitrary, the point of the experiment is to ensure that the alien and you adopt the same arbitrary definition. Therefore if we can get the alien to replicate the experiement so that we are both doing the same thing (in this case standing with our back to the current for example) then given all the other conditions are the same then we have got a shared definition of left and right. I do not have a nobel prize however so i probably have got this completely about face

 28623.  Fri Oct 28, 2005 3:51 am Clockwise and anti-clockwise are much easier than right and left to define because the universe exhibits rotational asymmetries all over the place, and therefore it doesn't matter which side of the table you're on - clockwise is clockwise. Say to the alien "get some crystalline feldspar (very simple chemical formula) and shine some light through it. The light's will turn clockwise (or anticlockwise - whichever it is, I can't remember). From this, you can define left and right. Prof Klein is merely saying that he's found another interesting outcome of his experiment - an asymmetry in the way that cobalt behaves in a magnetic coil (note that coils wrap clockwise or anticlockwise, not left or right), and could therefore be used as part of a verbal explanation to distinguish left and right.

28626.  Fri Oct 28, 2005 4:48 am

I still don't get it. I went and got some crystalline feldspar from Feldspars-r-Us and I'm holding it up to the light. When I hold it this way round the light rotates one way, and when I hold it the other way round it does the opposite. Or am I doing it wrong?

If it's easy to define 'clockwise' then it's equally easy to define 'right', isn't it? 'Right' is the direction in which the top of a clockwise rotation moves.

 Quote: it doesn't matter which side of the table you're on - clockwise is clockwise.
True, but it does matter which way up you put your clock.

 28637.  Fri Oct 28, 2005 6:26 am Some years ago I saw an Open University programme on this point, with people on earth trying to communicate left/right to an alien. It considdered various means which one might think could be used to distinguish left from right, but which didn't actually work. Then finally they came up with a solution ( I didn't understand it propperly, but it involved decay of K-zero mesons, if I remember correctly), and having used it to communicate with the alien they sent an astronaut into space to meet him/her/it. The astronaut held out his hand to shake, but the alien held out his left hand, and when they touched there was an explosion. Unfortunately the alien was from an anti-matter system and was studdying the decay of anti-K0-mesons.

 28642.  Fri Oct 28, 2005 7:13 am Flash, if I understand the point you are missing in Klein's chirality demonstration it is that the axis of the coil is vertical, so the current flows clockwise whichever side of the table you view it from (provided, that is, that you do not view it from the underside, but up and down are easy enough to define). To put it another way, if the electrons are propelled away from you the current in the coil as you are vewing it is clockwise, & vice versa.

 28643.  Fri Oct 28, 2005 7:16 am Wonderful. And I thought the OU was just a lot of '70s lecturers in beige suits and kipper ties droning on at 4 in the morning.

 28648.  Fri Oct 28, 2005 7:38 am I'm sure this programme was made after the OU's kipper tie period. I suspect that the progress of science has been advenced by OU lecturers/reserchers who are determined that the material in the programmes they have made becomes out of date, so that their lack of fashion sense is no longer exposed.

 28653.  Fri Oct 28, 2005 8:53 am Quaint This theory would be seem to be reasonable unfortunately many of the dons concerned have not actually moved on from kipper ties, and are blisfully unaware that fashion actually exists. The k meson thing is a good example of symmetry breaking and in fact was the subject of another nobel prize. What a bright buch we are that such a short discussion has resulted in having to refer to 2 major scientific advances http://nobelprize.org/physics/laureates/1980/presentation-speech.html

 28655.  Fri Oct 28, 2005 9:11 am "It is thought that no-one is truly ambidextrous (ie equally adept at everything with either hand), although quite a lot of people are mixed (eg they write left-handed but throw a ball right-handed). " And some professional cricketers bat one way and bowl the other, which always amazes me (but then, I belong to another overlooked minority: the doubly cack-handed, who are very nearly as useless with the dominant hand as with the other. Our ranks include a disproportionately low number of waiters.)

 104347.  Thu Oct 19, 2006 7:37 am Apparently, there has never been a left-handed Pope.

104354.  Thu Oct 19, 2006 7:57 am

 MatC wrote: And some professional cricketers bat one way and bowl the other, which always amazes me.

I had this conversation with my husband once, he being a fan of the game. He opined that all people who are right handed should actually bat what is known as "left handed". Not being an expert on cricket I couldn't tell you exactly why, but something to do with the hand which is uppermost on the bat actually being the dominant one.

Are there people who bowl with one hand and throw with the other? That would be harder to explain, but the equivalent is certainly not unknown among baseball players.

104370.  Thu Oct 19, 2006 8:29 am

 jaygeemack wrote: Apparently, there has never been a left-handed Pope.

That's interesting. Do we have a source for the assertion? It would be a tricky thing to prove, I should think.

119523.  Wed Nov 22, 2006 9:28 am

Flash wrote:

If it's easy to define 'clockwise' then it's equally easy to define 'right', isn't it? 'Right' is the direction in which the top of a clockwise rotation moves.

 Quote: it doesn't matter which side of the table you're on - clockwise is clockwise.
True, but it does matter which way up you put your clock.

But in which direction does a ferris wheel revolve. If you look at it from one side it goes clockwise but from the other side it is anti clockwise.

119530.  Wed Nov 22, 2006 9:40 am

 Quote: I had this conversation with my husband once, he being a fan of the game. He opined that all people who are right handed should actually bat what is known as "left handed". Not being an expert on cricket I couldn't tell you exactly why, but something to do with the hand which is uppermost on the bat actually being the dominant one.

As a sometime-cricketer myself, I always found that, as a right-handed batsman (ie my right-hand side is where my bat is, relative to my body) with the left hand at the top of the grip, it was the right hand that provided the power to the shot when pulling the shot across to the leg-side (and thus more dominant). The left hand, at the top of the grip provides no more than a hand to steady the bat, and provide additional finer control, helping to keep the ball down where necessary for example.
The opposite is true, when playing straight, or through the off-side. However, the cut shot requires a shot played square of the wicket, and a roll of the wrists (if keeping the ball down), and again, my right hand provides most of the ability. The left, once more, steadies the shot, and adds a little more fine control. My right hand is more dominant that my left (eg writing, for example, as well as throwing and bowling), and I find that I am a stronger player to the leg side. More leg side shots (Pull, hook, drive etc) need a stronger right-hand control, so that makes sense to me.

[/cricket waffle]

:-)

Tas

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