PastSellByDate, I don't think we are disagreeing about very much at all. I am not against studying old number systems. On the contrary, I very much welcome it as it helps children appreciate how powerful our place value system is. Try multiplying MMDCCXLII by CXXIV without converting to our number system first, which is what the Romans had to do.
In a historical context, of course we can take a look at imperial units as we can most other things, but that is not what is happening at present. We are in a crazy situation as I have described earlier in that we actually live in a metric world, but mostly the children see imperial units and they are expected to convert between one and the other. I am aware of Mr Goves new emphasis on conversion and even more familiarisation with imperial units and that is what I find so horrifying. Andrew Percy and his ilk just don't get it, to use a modern political phrase. What a coincidence that he also mentioned the car as an example, but did he tell us about the 10000 metric measurements that go into making a car? Not likely! All he said is that children see miles and miles/hour, which is exactly my point ...Why?
He also mentions pints for beer, but does he mention that the glasses that hold the beer and designed and manufactured in metric units, and the barrels that hold the beer, and the equipment that pumps the beer, and the equipment used to produce the beer in the first place and so and so on? Not likely!
And as to road signs, well the changeover to metric is long, long overdue and even the Government knows this. I have written to them several times to ask why this has not been done and every time they give a different answer ranging from the cost to the fact that they are waiting for at least 50% of drivers to have learnt metric units at school. We passed that stage years ago.
As to the cost, the Government estimates £800 million to change the signs; the UK Metric Association estimates slightly less based on the Irish experience, but even if we are generous and allow for £1 billion, that only works out at less than £3 per person per year if we spread the cost over five years. In Government terms that's absolutely peanuts and this is a once only cost - it will not have to be repeated year on year like most Government expenditure. By comparison, the O2 (formerly the Millennium Dome) cost £800 million and the tunnel they were thinking of building around Stone Henge a few years ago (now abandoned) was to cost £500 million.
In my opinion, people like Andrew Percy are doing untold damage to our children's maths education and because of his status as an MP, people listen to him.
Coming to your point about time, the first agreed definition of a metre was based on the distance from the North Pole to the Equator. The only reason for linking it to time via the caesium atom oscillations was to fix it more accurately and that is what modern scientists need to do to calibrate their instruments accurately, of course. I don't think I have ever said that time is based on 10. What I said is that the only metric unit for time measurement is the second (subdivided when necessary into milliseconds etc). We certainly use 12, 24 and 60 in everyday time, but that's a matter of convenience and not something that damages our children's maths.
Some people seem to think that because I advocate complete metrication in all aspects of everyday measurement, I think children should only be multiplying and dividing by 10. That's just nonsense, of course. What I am saying is that multiplying and dividing by powers of ten using metric units helps children to understand left and right shifting so that they can then go on to multiply by many other numbers. For example, a book weighs 456 grams, how much would 300 similar books weigh? Here we multiply by 100 by left shifting two places giving 45600 grams and then we multiply by 3, giving 136800 grams. If we wish to have this in kilograms, all we have to do is right shift three places to divide by 1000, giving 136.8 Kg. If we want this in tonnes, we divide by 1000 again (right shift of 3 places), giving 0.1368 t.
Finally, let me put it this way. Supposing we had been using metric units for hundreds of years and someone came along and said, 'Hey guys, I've just invented a new measuring system. We start with a unit of one inch which I randomly chose as the average width of some guys' thumbs and if we put twelve of these together we get a foot, which doesn't bear much resemblance to a real foot, but don't worry about that. Next, we fit three of these feet together and call that a yard. Are you with me so far? Next we put 22 yards together and that makes a chain, and ten of these make a furlong. Finally eight furlongs make a mile, and just to make it interesting we will put tenths of a mile on our car odometers that don't bear any resemblance to those furlongs I was just telling you about. Area, of course, will be the acre (lovely name, don't you think) and that will be the area of a rectangle one furlong long and one chain wide, giving 4840 square yards in an acre.
Now let me tell you about weight. There will be something called the ounce...'
Do you think it would catch on?
) but please, schools, do not inflict this confusion on the next generation!