h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Not sure how many people have watched these or what they thought of them. Interesting programmes I thought, populist science with enough in them to keep a fairly general audience. And no annoying multiply repeated cgi sequences!

BUT

I could not believe it when they showed the Kelvin scale and the plotting done thereon with all the scale references in *degrees* Kelvin! I mean come on, it's such a basic thing, one of those things people are constantly pointing out, surely they could have got that right?

Agreed. I learned that in schoolboy Physics. Science is all about pedantic accuracy - surely *someone* working on that programme would have pointed it out?

Darn it, I knew there was something I'd forgotten to record on my Sky+ box

Ah well, no doubt it will be repeated.

Orcus, I don't know how you feel about the use of torrent sites, but I can tell you that it is widely available out there if you so choose to look for it

Indeed. I shall be... watching it myself soon

So you're not supposed to used the phrase "degrees Kelvin"?

Seems like more of an audience thing - most people watching the show wouldn't know about that, and it probably helps to remind them what the unit refers to by adding the word degree in there.

Kelvin stopped being degrees kelvin until the 60s (or so says wikipedia) and thereafter the unit is termed 'kelvin' or 'kelvins'. There is no 'degree' to the unit.

Hardly surprising to hear 'degrees' with it in everyday usage. I for one didn't know it was illegal
and wonder if I'd have recognised 'kelvin' immediately without the 'degrees'. It's hardly surprising that broadcasters do it.

I entered 'kelvin' & & got the commercial site.
I googled 'kelvin' & only the third item was kelvin dot com, so Google management don't give it a high priority...

>>"It's hardly surprising that broadcasters do it."

I guess not, if they're scientifically illiterate.

In a programme specifically about low temperatures, you'd think it would be worth taking a few seconds to explain the non-usage of 'degrees' to the audience, assuming 'educate' is still in the BBC science mandate (though looking at a few recent Horizons, I guess it probably isn't).

** wonders what degrees Hertz they broadcast on **

No, no, no it's Hertz per second...

turvy

Surely a legitimate measurement of rate of change .

Traveller in Time not a clue about the show
"Some colour Temperature values, the unit is in Kelvin

Skylight (blue sky) 12,000 - 20,000
Daylight fluorescent (caution!) 6300
Design white fluorescent 5200
Special fluorescents used for color evaluation 5000
Sunlight (1 hour after dawn) 3500
100-watt tungsten halogen 3000
Candle flame 1850 - 1900
Match flame 1700

Fun is; if you extrapolate the graph, you will end below zero at the transmission frequencies "

For non-thermal light sources (fluorescents, LEDs, sodium vapour lamps) there may be an equivalent colour temperature, but it would be quite possible to have two non-thermal sources of equivalent colour temperature that had utterly different spectra.

For colour evaluation, having a good CRI may well make more difference than a precise colour temperature, though I guess it can be useful to standardise colour temperature for easy consistency when using multiple lights, though the point picked could be pretty arbitrary.