An excellent two-part documentary (4 and 11 January, 10pm) about Nina Simone was presented by the singer's daughter (called, rather confusingly, Simone), who referred respectfully to Nina as "Mummy" throughout ("Mummy's regal bearing . . . Mummy's onstage performance could be a little haughty").

Much was made, though smilingly, of Nina's obstreperousness, particularly when she suspected people in the audience might not be
listening. "Where are you going, man?" she challenged some chap once from her position on stage as he attempted to sidle off to the loo. "Sit down, man." The programme was tender and equable, the people interviewed speaking without rancour, even when criticising the singer ("I just assumed Nina was organically deranged, and that was all right by me . . .") and there was no sense of a producer trying to prise anything needlessly. There is nothing more tense than a documentary that suddenly feels like one is sitting over people as they steam stamps from envelopes.

One anecdote stood out: Nina's drummer recalled a gig to which she turned up on stage - this could even have been at the Vienna Opera House, somewhere smart anyway - carrying some plastic grocery bags that she dumped by the piano as she sat down and played 20 minutes of "Wild Is the Wind" ("You touch me . . .I hear the sound of mandolins . . .") in a low voice, entirely unharried, no disappearing off as she so frequently could into sudden smirking and swaggering verbal savageries. Then she stood up, recovered the bags and left. Nobody complained.

This led to a discussion about whether Nina enjoyed performing. A close colleague thought not. "Most of the time she just wanted to do the gig and get paid." He remembered her sly joy at discovering she could get away with flicking an amulet of hers - a donkey's tail - at the audience for whole minutes at a time, and them loving it and not asking her to do much more.

But then didn't John McEnroe hate playing tennis? Muriel Spark flinched at the prospect of writing. And all the chess players, of course - they hate every moment (but then a chess sense recognises that the perfect game would be free of mistakes. Nobody should win. Winning is a form of failure).

Possibly that is why Nina would chat endlessly between songs, giving the impression as she did of someone revealing dark secrets, someone tearing away at the husk of a pomegranate. Possibly it was not so much vanity as procrastination, her equivalent of cleaning out the fridge or wasting an hour researching a better speed of broadband.

A sweet series about the properties of air started this week (Thin Air, 12 January, 9pm, Radio 4). "Air the size of a sugar lump contains 30,000 billion molecules," thrilled the presenter, Gabrielle Walker, as she sat in a glider above High Wycombe, "which smash into earth at over five million times a second. That's a powerful force and that's what's holding me up! Julian, tell me about the thermals."

Julian the pilot was very charming and described how, at 62,000 feet, the blue sky evaporates suddenly into black. I like Walker's delighted, girlish voice. One can imagine her on the neat porch of a spotless stucco house sewing tags on to her children's clothes, humming. "I'm spiralling up!" she giggled at one point, inside a wind tunnel. "I'm swimming in this great ocean of air. I'm flying . . ."