TonyMcC

I wondered if it might put Elvis out of a job in Las Vegas. Or at least have him worried!

You can now be "married" by a coin slot machine for £1 (less than $2). What do you think of the idea? Could the evidence it supplies be considered a binding contract? http://www.bbc.co.uk/news/uk-england-cornwall-14003233

An interesting thing to me is how you might respond to increased speed of brain and muscle activity under critical conditions. Can you become a sort of superman for a short period if your brain decides that is necessary to conserve your life. It happened to me when I had to land a glider in a narrow field and collided with power cables (which are just about invisible from the air). The whole world seemed to go into slow motion for me. I had plenty of time to realise what was happening in the next, what must have been a very few, seconds. I changed my mind at least twice as immediately after realising what I had hit I let go of the controls and lifted my feet clear of the rudder bar. As the glider started to dip and slew I worked out that being in the air was my best bet and that electrocution was unlikely, so I got back on the controls, the glider responded. I levelled the glider about 3 feet above the ground, looked left and right to see if a snapped cable was coming with me and it wasn't so I made a normal landing. As I say everything described seemed to take ages. Obviously the world did not go into slow motion so my brain activity and physical movements must have working overtime!

The confusion arises because both pi and tau are used as symbols for different things. If you google- Greek letters mathematics science engineering - you will easily find a comprehensive list.

Can I change your first sentence slightly so that it is more in agreement with my thoughts and yet doesn't change its meaning? "The obvious advantage of using the diameter WAS that it WAS easier to measure than the radius". This could be a reasonable explanation of how the "unfortunate choice" was made.

There is one thing I discern through the general banter. Some people hold the view that mathematics would have been better served if the ratio circumference/radius had been adopted as a useful constant instead of circumference/diameter. Nobody seems to be saying that it is a good job that circumference/diameter was chosen rather than circumference/radius. From this I deduce that in historical times, for reasons appropriate to those times, an unfortunate choice was made. The best that can be said about pi is that it is so firmly entrenched that correcting this ancient poor choice just isn't worth the inconvenience this would cause. By the way, if the Swedish Bikini Team accept an invitation to the proposed conference can I come as a neutral observer? I'll happily bring some beer!

Cheers and bottoms up! I am in no sense a mathematician, just a retired lecturer in Electrical and Electronic Engineering (and other things). During the mathematical content of the syllabus just about every time I encountered pi it was multiplied by 2. Tau would have made life a little simpler (and the formulae more elegant?) for me and my students. I think you will understand that when I found an entry on today's news on this subject I found it interesting and wondered what "real" mathematicians would make of it. It would seem to be quite a contentious issue. Bob Palais seems a bit less tongue in cheek in this link :- http://www.math.utah.edu/~palais/pi.pdf

You can argue this one out with Bob Palais, Research Professor of Mathematics, University of Utah. In the meantime I'll have another beer lol!

I think the point is that tau/2 would rarely be used because tau,itself, would be used in most formulae. That's another way of saying pi (alone) is rarely used because "2*pi" is used in most formulae. Of course we who are used to pi might not like it, but future students who have formulae to remember and manipulate might benefit

It has been proposed that Pi should be replaced with the Tau for mathematical purposes. The Tau has twice the value of Pi. The reasoning behind this change seems to be that it would simplify many formulae since"2*Pi" is much more common in formulae than Pi on its own. This certainly seems to be the case in electronics and it seems some eminent scholars are convinced. What do you think?

Glad you are still alive !! it's very unwise to experiment with mains voltages so I suspect a bit of a wind up! Also the device is designed to work with a DC supply although the coil should tighten regardless of current direction.

I think this is one of those things that should work in theory but might be difficult to get working in practice due to the relatively high resistance of salt water when compared to mercury. I think,for example, that the resistivity of sea water is about 5 million times that of mercury. I don't know what the resistance of a pool of saturated salt solution would be but I can see that very high voltages might have to be used to get enough current to make either device operate (IMO). Anyway, best of luck and worth a try!

I am trying to imagine the orderly queues of people making there way to the emergency exits as the out of control plane gyrates and who then take it in turns to launch themselves into space. On a more serious note a quick chase around the Web indicates that there is a safety benefit from rear facing seats. It would seem that the survival rate of Air Stewards who sit in rear facing seats at the time of an accident is greater than that of passengers. As I have said before, I have travelled many miles in rear facing seats. Your view from a window is quite limited and moves very slowly. Most of the motion you feel is up and down and it is easy to forget that you are facing the rear of the plane. Perhaps, if the safety aspect can be confirmed, legislation should be considered. People will instinctively dislike the idea but I remember the same attitudes being held over motorcycle crash helmets and car seat belts.

If you have a mechanical system that is responding to force that is changing at its resonant frequency it is quite possible to damp the resulting oscillations. The amount of energy the damping system has to absorb will be relatively small. If you tried to extract energy from an undamped system this would have a damping effect on the oscillations - as had been said before, you can't get more energy out of the system than was put into the system which caused the oscillations.

Firstly there are crashes which simply are not survivable. Most survivable crashes (of large planes) are where the plane remains pretty much intact and slides along the ground before coming to a stop. In this situation although there may be fierce deceleration there may not be a sudden jolt. Car air bags require quite a jolt to set them off. It seems to me that an air bag may not inflate in many survivable crashes. Also in the cramped conditions most airline passengers have to endure,the air bags, if they inflated, could hinder rapid exit from an aircraft that may be on fire and rapidly filling with smoke. Whenever I flew as a passenger in British Air Force planes (VC10's in my time) all passenger seats faced the rear of the aircraft so that in a survivable crash you would not be thrown forward but the deceleration would press you into the soft, but supporting, seat back. I believe that civilian passengers would shy away from rear facing seats, but once in the air it made very little difference.

I would be interested to know what Mr Seater said. Was he apologetic or was it along the lines of "You people p*** me off"?

I don't think they are all that efficient, but you can already buy solar powered cooling fans for parked cars. http://news.cnet.com/8301-10784_3-6079960-7.html

Here is the BBC news report for you to have a look at if you like. http://www.bbc.co.uk/news/magazine-13874089

Sometimes its not so much what you see as what you feel. I was in Singapore at the time and stayed up most of the night to see this on TV. Terrible picture, but hope you can see it. It is Apollo 13 making the last part of its journey through the atmosphere.

Apparently they do worry about that in the UK as all water ready for drinking is covered. I'm not saying that a homeopathic dose of urine would worry me that much whoever or whatever it came from. However I can begin to see why the reservoir was drained. The water company would probably have been sued by any local person with a tummy bug!

The action begins to make sense after reading BBC news today. The water the man peed into had been purified and was ready to be distributed as tap water. According to the report this could not happen in UK as such water is stored under cover.

The only thing I can say about the first point is "Gee Thanks!" A couple of things to say about the second point is perhaps thinking speed and intelligence are not the same thing. For example many quite elderly drivers may be a bit slow with their reactions but remain safe drivers because they look and think well ahead - I think its part of what is known as wisdom. Also I rather hope that using my grey matter by following this site is one of quite a few things I do that keeps me "on the ball".

http://www.spacetoday.org/SolSys/Voyagers20years.html You might like to read this link.

You might like to read the following link. There could be a theoretical answer in line with the theory "the coin has no memory". However, if you spun a coin (say) 10 times in a practical situation and it came up heads each time the coin may not be a "fair coin" and so you might have more than a 50/50 chance of getting another head on the next spin. With a "fair coin" it is said that over a large number of spins the difference between the number of heads and the number of tails obtained will diminish. However, for all practical purposes all numbers of spin you use (even thousands) can be considered small numbers! With a fair coin the chance of getting a head when you spin is not affected by previous spins. It will be a 50/50 chance. http://en.wikipedia.org/wiki/Gambler%27s_fallacy

Do you get excited and enthusiastic about any ideas your students propose? IMO enthusiasm and excitement are catching!