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As a science teacher, I must agree with Roger Redman's concerns over the way we try to encourage engineering in schools (Letters, 28 April ). The new courses certainly offer little time to do experimentation or project work. Most skills requirements relate to writing about activities rather than performing them. And when teachers order equipment …

Not only is education lacking in practical material, as Redman notes , but in the European Union and North America there are ever-increasing restrictions on hobbies. These are based on fears stemming from rare, but heavily reported, incidents of children misusing tools or materials. In the 60s and early 70s, when I was young, I …

It is true, as Padman says , that philosophy does not prescribe the ultimate aims of science. It is crucial, however, that her statement of aims – to Explain Things – is inevitably a philosophical statement about science, not a scientific statement.

I enjoyed your article on meat substitutes ( 5 May, p 30 ). The innovations behind these are ingenious and welcome for their contribution to tackling climate change and resource availability. But these will be products and brands backed by venture capitalists who will enforce their intellectual property to protect a handsome return. As highly-processed …

Niall Firth mentions animal welfare issues as one reason for substituting meat. Expectations of what living is all about are difficult to determine for other species, and even in our own are greatly influenced by upbringing and experience. Eventually almost everything dies, but it is a presumption too far to imply that because we know …

Firth mentions leghaemoglobin being used in veggie burgers for colouring and flavouring. In 1906, J. Forrester , a pharmacist in Cleethorpes, UK, advertised "Forrester's Ferric Food: composed of organic iron... combined with a diastatic ferment prepared from malted barley and pressed out juices of fruits – a new remedy for consumption and wasting disease". Does …

Slapping currency value on nonmarket goods is fraught with problems and assumptions AjP is sceptical about calculating an exact accounting value for a tree, from its shade to its beauty ( 12 May, p 32 )

Sam Edge describes drawbacks of smart meters (Letters, 28 April ). It is now more than 20 years since I was at meetings with the UK government's then Department of Trade & Industry, where the smart meter idea was being proposed. At that time it was not seen as a scheme for remote meter reading, …

Everyone thinks they are a better-than-average driver, even if they have just caused a serious accident ( 12 May, p 42 ). But this delusional belief is apparently a sign of good mental health and makes us happy and contented. Will the same apply to a self-driving car? Will I be safer if my car …

• The study on koalas given antibiotics found that they had little effect on overall diversity of gut bacteria and did not definitively show that particular bacteria are essential ( 31 March, p 12 ). • Bling spring: diamond needles were bent by a nanoindenter inside a scanning electron microscope ( 28 April, p 9 …