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Your interview with Sugatra Mitra about children learning for themselves was fascinating ( 3 November, p 42 ). It chimed very well with research I did for a master's in education in 1989, on the role children wanted the teacher to play during group work. The 8-year-olds' conclusions were that the teacher should keep order, …

There are two ways this can end: badly and expensively. OK, just the one way @undeadbydawn reacts to UK police plans to use AI to predict whether individuals will commit violent crime ( 1 December, p 6 )

Ryan MacDonald notes that in the early 1990s Michel Mayor and Didier Queloz were the first to observe an exoplanet around a sun-like star ( 10 November, p 38 ). It was thought to be a gaseous "hot Jupiter" orbiting eight times closer to its star, 51 Pegasi, than Mercury is from the sun. Rocky …

I agree with Alice Bell's support for Dorothy Hodgkin to be on the new UK £50 note ( 10 November, p 24 ). Another aspect of her career is that she attended a state school, whereas each of the other 20th-century candidates mentioned – Rosalind Franklin, Alan Turing and Stephen Hawking – went to private …

It was very interesting to read Mark Lynas on the Union of Concerned Scientists' change of policy over nuclear fission power ( 24 November, p 24 ). I am, though, concerned that he did not find space to mention the relative contributions to global power use from the many different sources. He thereby implied equivalence …

Alice Klein looks at the impacts of disposable and reusable nappies ( 24 November, p 22 ). Bringing up two babies in the 1990s, living in a flat and working part-time, cloth nappies were a perfectly easy, though unconventional, option. I even air-dried them, but I had to be organised. I wonder whether the research …

You report that an imbalance in the gut's ability to repopulate itself with new neurons and clear out the dead ones could lead to Parkinson's disease ( 10 November, p 7 ) and that the disease may start in the appendix and travel to the brain ( 10 November, p 18 ). I wonder whether …

Anil Ananthaswamy reports work using cosmological sources of randomness in testing Bell's inequality ( 17 November, p 28 ) and thus quantum entanglement. There is a further problem, which philosopher Huw Price pointed out in his Time's Arrow and Archimedes' Point (reviewed 29 June 1996, p 42 ). He argued that if the laws of …

As I read Ananthaswamy's article on why "normal" physics can't explain reality, I began to understand the concepts of observer reality and non-locality. But as I read on further, I didn't. A bit further on I did. By the end of the article, I didn't understand any of it or how the described experiments were …

Guy Cox says that without a large moon there wouldn't be tides on a planet to allow marine life to progress onto land (Letters, 3 November ). But even on Earth, the tidal force of the sun is also quite strong – about 45 per cent of the strength of the moon's. So even without …