Letters archive

I can only conclude that Feedback is "directionally challenged". The meaning of the inscription on the face of Peter Groves's son's watch is perfectly clear; if you stand 100 metres from the watch and splash water at it, normal timekeeping will continue.

By chance I bought a new watch yesterday. Jewellery shops in Sydney have helpful displays to explain the grades of water resistance: WR for ordinary water resistance, light spray, sweat, light rain, as encountered in normal daily use; W50 for swimming but not suitable for diving, snorkelling, surfing; W100 for all water sports except SCUBA …

• Owing to an editorial oversight, an item found its way into Feedback on 17 July that should not have appeared in the column. We apologise to Astronomy magazine for stating quite wrongly that it printed an obviously inappropriate time in a diagram about the 8 June transit of Venus.

Water-resistant watches. Apologies for not being in any way witty with this reply, but I understood that "100-metre water resistant" meant that the watch could withstand a 100-metre static head of pressure (Feedback, 17 July) . Obviously, if you're (say) swimming, the dynamic pressure is far greater than the metre or so nominal depth your …

It seems reactive antigens and antibodies can be implanted into what is effectively a microchip, and there are "hundreds" of antigens and antibodies that have potential in this application (10 July, p 19) . Could you also beef up the capacity of computer chips by replacing the binary logic gate with something offering considerably more …

I was disappointed to find that Will Knight's article on spyware missed a key point that could have been extremely helpful to your readers (26 June, p 24) . While it did mention a couple of very effective tools for spyware removal, it made no mention of how to make your computer immune to much …

I read your article on myopia with great interest (10 July, p 12) . I too am quite near-sighted, and since early childhood, have been an avid reader of any printed material I have come across. I have by now reached the stage where I am unable to visit our local restaurants without compulsively reading …

With the wires Afhar has created a diffraction grating that will scatter the photons in precisely the way needed to recreate the original diffraction pattern but with the new (and unknown) paths for the photons to the detectors. Sorry, but the score is still Bohr 1, everyone else 0. The editor writes: • We have …

Peter Rowland argues that a process is more fundamental than its particles because we can only observe a process by observing the particles taking part in it (17 July, p 24) . However observation itself is a process. Chickens and eggs come to mind.

These wires will act like a diffraction grating, so that a photon from one slit may be diffracted into the detection channel for the other slit. In short, if the wires are there, we do not know which slit the photon came through; while, if the wires are not there, we cannot detect the fringes. …

Shariar Afshar has certainly built an ingenious set-up (24 July, p 30) . However, if his double-slit experiment performed as claimed, it would refute classical optics rather than standard quantum mechanics. His grid of fine wires constitutes a diffraction grating, which splits an incident beam into multiple beams at angular separations equal to the angular …

I am amused by the apparent revulsion over monkey tea (Feedback, 10 July) . My wife is of Chinese extraction and confirms that monkeys are used to collect herbs from places inaccessible to humans. Monkeys are also used to harvest coconuts in many countries, and cormorants to catch fish in China. No doubt there are …

How can the scientific and business communities combat the widespread misuse of the term "renewable energy"? The subject of Renewable Energy: Practicalities, the House of Lords report reviewed by Jenny Hogan and Philip Cohen, was in fact renewable electricity. This is a clear demonstration of the UK's civil service using "renewable energy" to refer only …

Tam Dalyell's piece about the impact of air traffic on climate change addresses a vital issue that is often obscured by the debate about numbers (17 July, p 45) . Our fundamental concern is that a policy permitting unhindered growth in airport capacity directly contradicts the UK government's goal of reducing carbon dioxide emissions by …

What a curiously narrow approach you are taking to the optimum way to match the UK government's sustainable energy targets (17 July, p 6) . There really is a lot more to this debate than the simplistic wind versus nuclear power equation. Energy policy is not just about supply: it is every bit as much …