Precision on the Beeb

Slightly surprised that no mention made here, thus far, of the Beeb's series 'Precision' - introduced by Marcus de Sautoy.

Utterly fascinating, covering topics which I would have thought dear to the heart of engineers - professional or otherwise. Absolute gems, like the inability of machinery to produce a Kg sphere at a precision to match (or better) the HAND formed version of an Australian. The search for precision in weight , distance etc. is almost obsessional - 40 years work to try to perfect the Watt balance and still not there. Highly recommended watching and available on Iplayer for those who have access.

Rgds

Bill

Bill,

Yes, I agree, a hugely enjoyable and educational program. Note part 1 (at least) is only available on iPlayer for another 5 days, I watched it meyself on iPlayer last night having forgotten to record it. Have not watched part 3 yet, but at least I have recorded it.

Should be shown in schools IMO. I do wish there had been slightly less time spent on soulful staring into the distance and more on the nuts and bolts aspects, but then we are all here, I suppose, that way inclined.

On the hand production of the silicon sphere (as a standard kilogram) it reminds me that back in the 70s one of the major Japanese camera companies (I think it was either Canon or Minolta) said that they used highly skilled workers to check the curvature and finish of their glass lens elements, as they were more accurate than machines. Thus this part did not surprise me.

David

Fascinating. I searched for 'handmade kg sphere' and found this: **LINK**

In school we were taught 'bucket chemistry', I suppose that was 'bucket physics'.

I did find a description of the sphere, and other better ones: **LINK**

Neil

I was a rather surprised at his comment that adding copper/zinc/acid layers to the early battery increases the current. It doesn't; it increases the voltage.

The second surprise was his comment that Farenheit chose zero on his thermometer as the freezing point of water, whereas zero is actually the freezing point of an equal mixture of water, ice, and salt. The freezing point of clean water is 32F.

Far too much much attention to flashy graphics and not enough to precise facts.

Makes you wonder at how many other errors got lost in translation

A few years ago I followed the fortunes of the NASA 'Gravity B probe'. From memory it contained two spheres about 50mm diameter that if enlarged to the size of the Earth would have a maximum surface deviation of 2m.

I think that is an even greater level of accuracy than what was quoted for the Kg standard by the BBC presenter? One super critical factor for the NASA spheres was that material had to be truly homogenous which I think was quartz..

Ian P

This is a link to a description of the spheres

Ian P

**LINK**

Could someone post what time/ day/ chanel this programme is on please?

Thanks
Diane

Diane

Its a series of three on BBC 4. I think two are already shown so the best thing is to look on iPlayer before they disappear.

IanP

Hi Diane,

All three have been shown now. There may be repeats. Four days left to watch on iPlayer.

**LINK**

Gary

Hi Diane,
I player also gives the option of downloading these three programs to view at a later date. They can only be viewed for 30 days from the download and I think they can only be viewed on the computer that was used to download them. They are quite large downloads. (About 600 megabytes.)

Les.

Thank you all.

Diane

After reading this last night I watched episodes 1 and 2 this morning after the dawn chorus had me up at 4am

Even though I must admit to nodding off due to my early rising I did enjoy watching them and will give them and episode 3 another go when I am more awake

A bit of proper science doesn't hurt once in a while (although some may question the "proper" bit)

John

I seem to recall he creditid Henry ford with the concept of standardisation, and no mention of a certain

Mr Whitworth quite a few years before old "enery". Once i spot an error like that i tend to question the rest.

Cheers Derek.

I think the US watch industry had discovered the benefits of standardisation (interchangeable parts) long before the motor transport industry.

Ian

Rifle makers were major drivers of standardisation during the civil war 1862-1865 in the USA. It was imperative to have interchangeable parts to keep all possible rifles working - they could not keep up with demand. The watch industry would have been working on standardisation at around the same time in USA. Certainly both were working on it LONG before Henry Ford (or rather, his very capable staff) concentrated on it.

I'm sure Whitworth was working around that time or maybe before it.

JD

Yes, I noticed that too. I also noticed that although he credited Edison for the electric generator, he didn't even mention Faraday who discovered electro-magnetism and made Edison's invention possible.

Edited By Gary Wooding on 28/06/2013 07:22:43

Every scientist/engineer relies on the discoveries of their predecessors. It's impossible to mention them all in a programme like that.

BTW. Hans Oersted discovered electro-magnetism before Faraday.

Russell.

Just watched the first one, and his credibility was somewhat clouded when he said the Egyptian Cubit was the forerunner of today's Rulers!

Rule, rule, RULE.

Still highly educational and worth watching though, so will be viewing the others tonight.

Oh, just don't start me off about the latest car craze described as drifting when it should be POWER SLIDING!

Power sliding is easy with enough HP, but drifting a car requires more finesse as I found out in my 105E Anglia going into Sunset at Kyalami, the original F1 circuit, in the 70s.

Geoff - Time to get into the roof space to sort out water tank valve that's leaking.

Hi, I think the piont about Henry Ford and standardisation was the way he delt with the cocept of every part that was to be used in the cars to be standard in order to mass produce at the lowest cost possible.

Regards Nick.

Not having seen it, I hope he explained the difference between 'precision' and 'accuracy' properly. Those spheres have to be BOTH to be useful.

Neil