Each year for the past twenty years I recall someone mention the idea of moving the UK’s time zone to CET, or changing daylight savings or some other such tinkering with the clocks. As I have come to understand time more and more this confuses me more and more. Not that I am confused by the concept of changing a clock, I’ve done that enough that it doesn’t matter to me, but my confusion is to why we need to change a unit of measure rather than changing our attitudes. One of the arguments for changing timezones or using DST is for “safety”, the idea is that if it is too dark in the mornings people going to work or school are more at risk. It is also said that energy can be saved because people wouldn’t use so much lighting if the clocks were different.

What this fundamentally ignores is the fact that time itself is not really variable, not on a scale that matters to our daily lives anyway, in each SI day there are 86,399, 86,400 or 86,401 seconds (yes there are not exactly 24 hours in a day because the earth isn’t perfect). When people talk about fiddling with the time they are really just doing it for political reasons, to assert themselves and their own importance. If it really mattered about the time at which children went to school then schools could open earlier or later, businesses can make their own decisions about when to open and operate. I currently work at a business that opens at 08:30, but I have started at 05:00, 08:00, 09:00 and 10:00 in differing jobs. Delivery drivers, bakers, presenters and many more people get up at a time that suits their work (Shift Work). I once worked with a team that didn’t even assume a 24 hour day, they worked on a short but intensive cycle over many days, living on site and then had a long period off at home.

I imagine the counterpoint to the argument is that if schools started earlier then people would be in difficulty if their employer didn’t change the hours. But already it is difficult for people who are constrained by employers who enforce archaic working practices, changing the clocks isn’t going to make better employers and if children went to school earlier then it wouldn’t be as bad for parents worrying about getting to their 8am start at work. There is supposedly evidence that indicates that some deaths on the road, especially those of commuting school children, can be attributed to poor light levels. Well, I would point out that if the children were to leave school when it was more light (irrespective of clocks) then they would be equally likely to be outside on the streets (doing whatever children do) afterwards which wouldn’t make it much more safe.

On the BBC Internet Blog, Andy Quested has discussed the various issues around the addition of a test signal to BBC HD. It makes for very interesting reading, well worth it for anyone wanting to better understand their television and get a better picture.


I actually emailed Andy about one part of his article:

 “The audio is actually two blocks of wood being banged once a second – nothing to beat the real thing!

I emailed him to say that in college one of my much respected lecturers (Morgan Jones) proposed using a spark gap as a syncronisation source. Few things in nature are more instant than a spark and the correlation between the light and the light is absolute (subject to the speed of sound, etc).

His response was that he would look at it but he also raised another issue, how do you deal with the fact that an audio compression system based on the psycho-acoustic model might ignore such a short spike of audio? Frankly I don’t know, I am not sure I know enough about compression systems, but it seems worth a look.