Â鶹´«Ã½

Philip Ball writes about the universality of music (8 May, p 30) . One reason that music is important to people around the globe is that making or listening to it is almost always a positive experience, be it joyful, restorative, transporting or cathartic. This is significant in an evolutionary sense, because we big-brained creatures …

I was excited by the prospect of reading Ewen Callaway's article about Neanderthals interbreeding with Homo sapiens (15 May, p 8) . But I was disappointed on reading it to be left with the impression that the editorial crew involved must have been a bunch of white guys, wearing white-guy blinkers. Callaway reports that the …

Your editorial condemning gene patents describes as "tenuous" the argument that "isolating a gene upgrades it from a discovery to an invention" (10 April, p 5) . While it is true that discovering something as it exists in its natural state is not classed as an invention, isolating something and finding a practical use for …

Lakshmi Sandhana reports on Petimo, a robotic computer interface that, it is hoped, will protect children from the dangers of strangers on the internet by acting as an intermediary during social networking (8 May, p 22) . You quote the device's inventor, Adrian David Cheok, as saying that he wants to use Petimo "to help …

Keith Ross's explanation for the Mpemba effect doesn't make sense (24 April, p 25) . He asserts that a container stratified with room temperature water separating ice at the top and 4 °C water at the bottom would not have convection. That is not true: the warm layer in the middle would touch the ice, …

Franco Cappuccio and Simon Capewell make an assumption in their article on the health risks of eating salt: that what people want more than anything else is to live for a long time (1 May, p 22) . Some people consider it more important to enjoy life than to live as long as possible, and …

Your article on microbes surviving in the Pitch Lake in Trinidad (24 April, p 15) reminded me of being told while on a visit there that convection currents in the asphalt create areas similar to subduction zones. In the wet season, when these areas fill with water, guppies can be found swimming there – a …

I was dismayed to see that Â鶹´«Ã½ has dumbed down to the extent of needing an analogy for the graph of a quadratic equation in Stephen Ornes's article on playing pool (8 May, p 34) . He could at least have picked something the right shape. Lest we forget, a rainbow is an arc …

• The experiments into the Mpemba effect, detailed in Keith Ross's letter, were carried out by student teachers in training, not by primary school students (24 April, p 25) .